What is a term for iterating over many functions with the same input?

Question: When we call the same function on a list of things, we call that "map".  What do we call it when we call a list of functions on the same data?  I don't mean pipe - not feeding the output of each function in turn into the next function - but simply iterating over a list of functions, passing each the same input?
Comment: In my day, we used to call that "calling a list of functions with the same input."
Comment: Using [Flynn's taxonomy](https://en.wikipedia.org/wiki/Flynn%27s_taxonomy), I would suggest [MISD](https://en.wikipedia.org/wiki/MISD) (multiple instruction, single data).
Comment: I think calling "collection" of different methods with same signature(input) is what event and eventhandlers does. When you raise an event all eventhandlers executed with same input parameters. I think "delegating" is ok word.
Comment: This is a fairly easy example of the Visitor pattern -- maybe you'll find your verbiage researching that.
Answer: I do not know of any term for your operation, but it can be seen as a kind of mapping, so maybe you do not need a special name for it. I will illustrate this in Haskell, but it is easy to do the same in other languages, e.g. Python, Clojure, Javascript, etc.
In Haskell map has type:
map :: (a -> b) -> [a] -> [b]

For example, you can map length over a list strings:
xs = ["Good", "morning", "world"] :: [String]

> map length xs
[4,7,5]

Now suppose you have a list of functions, e.g.
fs = [(+ 1), (* 5), (* 2)] :: [Int -> Int]

How can you apply each function to the same number, say, 1? You can use the function:
($) :: (a -> b) -> a -> b

This function takes another function and applies it to an argument. If you partially apply it to the number 1, you get:
($ 1) :: Num a => (a -> b) -> b

This is a function that given a function from a numeric type to any type b, applies it to 1. So, now we can map ($ 1) over our list of functions:
> map ($ 1) fs
[2,5,2]

So, in general, given an input x :: a and a list of functions fs :: [a -> b] you can apply all the functions to x with map ($ x) fs, which gives you a result of type [b].
Comment: Excellent.  I suspected it was just another variation on `map`, but couldn't articulate an answer well enough to prove it.


Assumptions of two way anova

Question: Please tell me what the actual assumptions of a two way anova are. I read somewhere that this being similar to multiple regression, the only assumption is that the residuals are to be normally distributed with equal variance. But then a web search gave the following assumption "Two-way anova, like all anovas, assumes that the observations within each cell are normally distributed and have equal variances". I am confused. Please help out.
Comment: What exactly are you confused about? The two descriptions sound the same to me.
Comment: If the model is "true," the statements are equivalent: $\varepsilon_i\sim N(0,\sigma^2)\Longleftrightarrow y_i\sim N(x_i^T\beta,\sigma^2)$, since $x_i^T\beta=\mathbb{E}[y_i|x_i]$. I'm not sure if I got that precisely right, but that's the idea at least. This is why people use the term "variance" so loosely when they talk about regression, because it doesn't matter which one they're referring to.
Answer: There are a number of assumptions that apply to two-way anova if you're performing inference; different people will place more or fewer things into the assumptions or into the model or leave them as obvious/implied, but a basic list for the most common tests/intervals is probably:

independence. The observations are assumed to be independent.
equal variance. The observations (equivalently, the errors) are assumed to have equal variance.
normality. The errors (not the residuals!) are assumed to be normal. Equivalently the observations within each combination of factors are normal. However, since we don't have access to the errors, we examine this assumption by reference to the residuals, which (if the other assumptions hold) will approximate them.
The values of the factors are known/fixed.
The form of the model for the mean is correct.

The last two are often omitted from the list but they're still there.

Assumptions of two way anova


Can the vertex angle of an isosceles triangle be found without the law of cosines (no calculator)?

Question: If we know three sides of an isosceles triangle, can we find the measure of the angles without using a calculator (that means no law of Cosines/Sines).
Comment: Depends on the meaning of find. One can use the definition of sine.
Answer: Call the sides of the triangle lengths $a$, $a$, and $b$. Drawing a line of symmetry through the triangle lets us divide the triangle into two right triangles. Hence we can calculate $$\cos(\theta)=\frac{\frac{b}{2}}{a}=\frac{b}{2a}$$
where $\theta$ is the repeated angle in the triangle. This tells us the angles of the triangle are $\theta$, $\theta$, and $90-2\theta$, where
$$\theta=\cos^{-1}(\frac{b}{2a}).$$
Answer: Yes.  We can use the law of sines.
That is, choose two sides of unequal lengths $a$ and $b$.  Let $\alpha$ and $\beta$ denote the measures of their respective opposite angles$.  Then we have:
$$\frac{\sin(\alpha)}{a} = \frac{\sin(\beta)}{b}$$
If $a < b$, then $2\alpha + \beta = 180^\circ$ since the triangle is isosceles.  From here, we have $\beta = 180^\circ - 2\alpha$.  Plug this into the above, and we have an equation with a single unknown.
Comment: I meant more in the spirit of not using a calculator when I excluded using the law of Cosines, and this method would still require a calculator.
Comment: Oh I understand, sorry about that.  I'll leave my answer up anyhow since others might get something out of it.


Double tap interval time standard

Question: Is there any standard, say ISO standard, for interval (in miliseconds) between to taps ( clicked on touch devices) which assumed as double tap?
I guess it should be long enough to allow slower users to double tap, but not so long that leads to mistakes.
Answer: I think this is similar to the click/dbl-click issue http://en.wikipedia.org/wiki/Double-click#Speed_and_timing

The maximum delay required for two consecutive clicks to be interpreted as a double-click is not standardized. According to Microsoft's MSDN website, the default timing in Windows is 500ms (one half second).

So, apparently, it's not standardized. I'd say tapping is slower or equal to clicking (it will depend on the relative position of the hand to the device), but still 500ms sounds reasonable.
Answer: Warning: Speculation :)
Probably not.  Something this central to the "feel" of a UI would not translate well across different input device types, or even different builds of the same device type.
For example, one touch-screen might be much more sensitive than another.  Another device might be more erratic, and require more software "de-bouncing", and hence more time to make the double-tap distinction.
Also, this setting is usually configurable for greater accessibility by those who are less dexterous (e.g. children, elderly, and the disabled).
For a direct counter-example, in Windows, it is configurable:
Answer: If there is, nobody adheres to it.  I believe most systems allow some sort of configuration for this.  Some people (even with old systems that use mice) can't physically click fast enough to trigger a DoubleClick.  They have to modify the system settings.

Double tap interval time standard


Visual Studio Code won't stop at breakpoint in PHP Xdebug

Question: I have move from my Thinkpad laptop to HP Elitebook. I must set my development environment in my new laptop. After setup my Visual Studio Code and XAMPP in Windows 10 Pro 64 bit edition, I can't debug my PHP code.
I have properly installed Xdebug extension for Visual Studio Code, and make sure the php.ini correct. This is my setting for php.ini (I use portable XAMPP which is placed on E: drive):
zend_extension = "E:\xampp\php\ext\php_xdebug-2.4.1-5.4-vc9.dll"
xdebug.remote_enable = 1
xdebug.remote_autostart = 1
xdebug.remote_log="E:\xampp\apache\logs\xdebug.log"

And my xdebug.log show information like this :
Log opened at 2018-10-27 05:56:45
I: Connecting to configured address/port: localhost:9000.
I: Connected to client. :-)
-> <init xmlns="urn:debugger_protocol_v1" xmlns:xdebug="http://xdebug.org/dbgp/xdebug" fileuri="file:///E:/xampp/htdocs/absen/index.php" language="PHP" xdebug:language_version="5.4.3-dev" protocol_version="1.0" appid="7112" idekey="william"><engine version="2.4.1"><![CDATA[Xdebug]]></engine><author><![CDATA[Derick Rethans]]></author><url><![CDATA[http://xdebug.org]]></url><copyright><![CDATA[Copyright (c) 2002-2016 by Derick Rethans]]></copyright></init>

-> <response xmlns="urn:debugger_protocol_v1" xmlns:xdebug="http://xdebug.org/dbgp/xdebug" status="stopping" reason="ok"></response>

Log closed at 2018-10-27 05:56:45

But my Visual Studio Code won't stop at breakpoint.
I have reinstall my Visual Studio Code, XAMPP, and using another Xdebug version but it still doesn't work.
I have follow these links:

visual studio code PHP debugging not working
xdebug won't stop at breakpoint
xdebug breakpoint fail
Xdebug successfully connects to DBGP clients, but won't stop at breakpoints

None of these solutions work.
Answer: Finally i know the source of problem. The HP Elitebook have preinstalled program named HP Velocity, which used port 9000.
The issue is port 9000 from my host is bind to port 9000 of HP Velocity software. When HP Velocity service connect to the localhost xdebug server, logs say that connection is ok, but it is connected to HP Velocity.
I changed xdebug port to 9090 in php.ini and changed in launch.json on visual studio code. After that, my visual studio code work as usual and can stop at breakpoint.
Hope this help others :)
Comment: Probably you can use netstat
Comment: Is there a way to get a list of which ports all programs are looking at?
Answer: This is what fixed the same issue i was having,worth the shot if previous answers didn't help
php.ini
 [XDebug]
zend_extension = "C:\xampp\php\ext\php_xdebug-3.0.2-8.0-vs16-x86_64.dll"
xdebug.mode = debug
xdebug.start_with_request = yes
xdebug.client_port = 9000
xdebug.client_host = "127.0.0.1"
xdebug.log = "C:\xampp\tmp\xdebug\xdebug.log"
xdebug.idekey = VSCODE

launch.json
"configurations": [
    {
      "name": "Listen for XDebug",
      "type": "php",
      "request": "launch",
      "port": 9000
    },
    {
      "type": "php",
      "request": "launch",
      "name": "Run using local PHP Interpreter",
      "program": "${file}",
      "runtimeExecutable": "C:\\xampp\\php\\php.exe"
    }
  ]

Comment: I had Ubuntu 20.04 with the same problem and this works like a charm! Thanks.
Comment: In my case, using VS Code on a Mac and remote container debugging, the specific ini file settings that resolved my issue where xdebug.mode = debug, xdebug.start_with_request = yes, and  xdebug.idekey = VSCODE
Answer: In my case, the pathMappings was incorrect, and did not change the port
{
    ...
    "configurations": [
        {
            ...
            "port": 9000,
            "pathMappings": {
                "/var/www/yourproject": "${workspaceFolder}/",
             }
          }
      ]
  }

My Breakpoints is actually working if I check the "Everything" breakpoint
(It captured a suppressed exception, but VS code alerted that the file was no found)
Comment: I thought my issue had to do with the pathMappings setting as well. It turns out the trailing / is important. Adding that solved my issue right away.
Comment: This was key for me, trying to setup xdebug using WSL running Docker (Lando) containers.  My breakpoints were flipping from active to unverified suggesting the xdebug request was being transmitted and received (client-host/port were correct), but it wasn't stopping at the breakpoints.  Note that the left side is the path from the platform your site is hosted on.  For example, with Lando that would be "/app".
Comment: Strange. did this need for trailing / start with xdebug 3? my config was working without it up until today on an xdebug 3 setup
Comment: I really don't understand yet why we would need to use an absolute path, or trail workspace root with a slash, but that solved my issue too. I'm working with Local by Flywheel, WordPress, current VSCode, PHP 7.4.1 (the same php.exe for Local and the VSCode PHP workspace) and the corresponding NTS XDebug 3 for Windows x64  `"C:\\Users\\tonyg\\path\\LocalSites\\sitename\\app\\public\\": "${workspaceRoot}/"`
Answer: In my case, I was trying to debug a php script on my local machine, so I had to realize that I had to debug the php script using the port  which the Web Server is using (8080 in my case) rather than using the port set on the VS Code configuration (I use 9090).
For anyone who is stuck with this error, this is my configuration:

OS: Windows 10 64 bits
PHP 5.6 (32 bits TS)
Xdebug 2.5.5 (32 bits)
Apache 2.4 (32 bits)
Xdebug Helper installed on Google Chrome

1) httpd.conf

2) php.ini (XDebug section)

3) launch.json (VS Code configuration)
Answer: The reason might caused by the port of php xdebug.It works for me fine when I did this:
1.use php --ini to show php config file and change xdebug port to 9900:
xdebug.remote_port=9900
then restart your php
2.open vscode and change the port to the same number in launch.json:
"port": 9900
3.enjoy your debug
Answer: I am a novice programmer so this will probably sound dumb, but might be helpful to someone new to PHP and web servers like me.
I had the same issue with Xdebug skipping a break point. For me it turned out to be that I had a break point on an "echo" statement. Apparently that is not a valid line for using a break point. It started working once I moved the break point to a variable declaration.
Comment: In fact, that ***is*** a valid line for a breakpoint. I wonder who upvoted this
Answer: Please note if you are using Xdebug version 3.xx you need to do the following:
Stop Apache server, then in php.ini add at the end of the file:
[XDebug]
xdebug.mode = debug
zend_extension="C:\xampp\php\ext\php_xdebug.dll"

After that, start Apache server agian.
Note that adding xdebug.start_with_request = yes will tell xdebug to initialise communication with an IDE for every request even though you might not debugging, which gives a warning in your IDE console state:
[Step Debug] Time-out connecting to debugging client, waited: 200 ms. Tried: localhost:9003 (through xdebug.client_host/xdebug.client_port) :-(
It's better to use a chrome extension to trigger the activation of xdebug using a cookie in your browser. See https://xdebug.org/docs/step_debug#browser-extensions for more information.
In vscode go to Run in your top menu, then Add configuration, this will open launch.json, add under configurations:
{
    "name": "Listen for Xdebug",
    "type": "php",
    "request": "launch",
    "port": 9003
},

Please note that port 9003 is different than your app port. I'm running my laravel app using: php artisan serve with port of 8000 and in my launch xdebug is 9003.
Re-run your debug in vscode and should be working.
I wish you the best in your bug-fighting war!
Answer: I had same issue but after change port to 8000 in ubuntu it works for me.
Answer: I saw the same issue, running ./vendor/bin/phpunit -c <config file> was causing all of my breakpoints to be disabled. I was only able to debug if I checked "Everything" and sorted through all the junk.
I updated the pathMappings in my launch.json file, and added a new launch configuration with a different pathMappings to work locally
{
    "name": "PHP Unit Test XDebug",
    "type": "php",
    "request": "launch",
    "port": 9001,
    "log": true,
    "externalConsole": false,
    "pathMappings": {
        "${workspaceFolder}": "${workspaceFolder}"
    },
    "ignore": []
},

I found this solution from this SO post, and this one here Debugging PHPUnit tests in VS Code?
Answer: Turns out the shell environment variable XDEBUG_MODE overrides the xdebug.mode setting in your php.ini, and I was setting the XDEBUG_MODE variable in my .zshrc file (likely a configuration from a previous project that I had long forgotten about).
In short, if xdebug isn't working and you've seemed to follow all of the instructions about setting up your IDE and php.ini file correctly, make sure you aren't inadvertently setting XDEBUG_MODE somewhere else.


How can I do a force restart?

Question: I'm wondering once I'm in Kodi and it freezes what do I do? Is it possible to force quit the program? or is there a way to do a reboot of the system? It's happened a few times now where the system freezes and I seem to always have to pull the power to reboot. I'm wondering if there are better steps to do before It comes to that. Does that make sense?
Answer: Try CtrlAltF1-6.  At least one of this should take you to a plain text login.  From there you should be able to get the PID of the Kodi process -- presuming it's called kodi, which I don't know:
ps -C kodi

This will respond with a number, or nothing it it is not actually called kodi, in which case you could try ps -A | grep kodi to see if it is something more elaborate (e.g kodi-foo). Once you have the PID number:
sudo kill ...

Where ... is the number.  If that doesn't work, try kill -9 ....
If/once you are sure of the name of the process you can also just use:
sudo killall kodi

To save looking up the PID. You can use -9 with killall.

How can I do a force restart?


Linear Regression with vs. without polynomial features

Question: I have a conceptual question about why (processing power/storage aside) would you ever just use a regular linear regression without adding polynomial features? It seems like adding polynomial features (without overfitting) would always produce better results? I know linear regression can fit more than just a line but that is only once you decide to add polynomial features correct? My experience with python using sklearn's libraries.
Comment: Polynomial regression is extremely dangerous for extrapolation.  If you only want interpolation then other methods such as splines or generalized additive models can provide more flexibility than simple polynomials.
Comment: It depends on your model and data. Do you have a prior on your data? Do you know that it is linear or not? Do you want to extrapolate?
Answer: At a minimum, you should consider cross-posting this to the Data Science stack exchange site (stats is more in tune with the statistical, ie math, underpinnings).
That said, there is a trade-off between variance and bias in pretty much every model of this sort. Essentially, there are a few factors here.

Overfitting. You dismissed this with a handwave but it's one of the most critical aspects. A high bias model (fewer parameters in this case) helps guard against overfitting -- but at the cost of sensitivity.
There is a sweet spot in increasing the complexity of the model. At some point, it might not improve the fit to the training data.

Additionally, that hand-wave of setting "processing power/storage aside" really is non-trivial as are the labor-hours involved.
I hope that helps but, again, this (and a number of questions like it) are better asked here.
Answer: There's a lot of nuance to this, as a general rule you chose the simpler model all things being equal. After building a polynomial model, you can F-test against a first-order model and go from there. Here is a link to more on this.


China visa application: arrival flight connects to a domestic flight. Which flight number do I put down?

Question: I am a British citizen filling out a visa application form for China, but I am struggling on what to put as my flight number for my arrival flight as it is from the Philippines and contains two flights. The first is from Manila to Guangzhou, and then a second flight from Guangzhou to Wuxu Airport in Nanning.
I'm concerned that if I put the second flight number that it won't look like it's my arrival flight on the application form, but if I put the first flight number, will I have to validate my visa on entry at Guangzhou?
Comment: Won't you have to go through immigration, validating your visa, to get from an international arrival to a domestic departure at Guangzhou anyway?
Comment: @PatriciaShanahan yes that is correct
Comment: Imagine a US citizen were flying from San Diego to Edinburgh, changing planes at Heathrow, SAN->LHR->EDI, on a single booking. They would go through immigration and customs at Heathrow, and that would be their point of entry. The domestic LHR->EDI flight would also have people just traveling from London to Edinburgh, and have no immigration checks on arrival at Edinburgh.
Comment: Have you checked out the 144 hour(5 days) visa free transit if you're not there long?
Answer: Put the first flight which takes you into China. You will have to pass through immigrations in order to get to the domestic gate for your second flight.
You may also have to re-check your checked-in luggage as well.
So you list the flight that brings you into China from abroad, you do not list the domestic flight as you do not need a visa for domestic flights these days
Comment: I upvoted you, but you might wish to make it clearer that they should list the first flight, where they actually arrive in China, on the application form.
Comment: No, they're referring to Nanning Wuxu Airport: https://en.wikipedia.org/wiki/Nanning_Wuxu_International_Airport
Comment: @lambshaanxy ok it wont change anything though
Comment: When I went to China the visa application asked for my itinerary. I did list internal flights there. I don't know whether that is still required.
Answer: The first flight, so the flight which define your port of entry (and times), in case they need to check you.
Comment: In case? Of course they will check when you pass immigrations
Comment: Check and cancel your entry so it cannot be used again.  OP is not transiting.  On a two entry visa they would cancel each entry in turn.
Comment: I should edit my answer (later). I was stopped, but in short: they found you are possibly a criminal (from records, e.g. same name), maybe someone will check you (your face) to see if you were the searched one. Port of entry keeps your paperwork: if you misbehave, they may check original paper, to find an excuse to ban you. "Excuse" because it is not the real reason, but probably the most efficient way. Don't be scared about this, this is for bad guys.


How creating new language (package, styles,babel script?)

Question: I write a dictionary of artificial language.
Where is any tutorial how creating new language. I have 12 unicode characters and 2 characters in two different representations and normal romna and greek characters. (join 2 glyphs for example o+' = ó)
Some characters have dots on top (similar i or 2 dot) and ogonek (similar cedila?).
Comment: Your question is somewhat vague. Would the tools described in the `babel` docs under "Creating a language" help? What "new unicode characters" means?
Comment: new unicode char = character outside normal roman table, nothing more. I ask about documentation , please give me link. This is only alphabet not language. I dont know what is better, style, babel etc. Alphabet for me is charmap, hyphenation, some joining character (in polish a+,=ą) . Question is how change unicode character to letter or joining 2-3 glyph.
Comment: You can find the babel docu at http://texdoc.net/pkg/babel/
Comment: @JavierBezos In the version (Version 3.12 2017/06/29) currently included in texlive, the table of contents seems to be missing in the documentation.
Comment: @samcarter Thank you. I realized after submitting it to CTAN. Not being a severe problem, I'll fix it in the next release (sep-oct, I think).
Comment: @MarekKaski Your TeX distribution should include the manual (babel.pdf). You can find it on https://ctan.org/pkg/babel .
Answer: From TeX's viewpoint, a "language" is only a set of hyphenation patterns to allow the processor's paragraph breaking algorithm to do its typesetting job: hyphenating a paragraph. So, once you have figured out the phonotactics of your conlang, you only need to define a set of hyphenation patterns as the argument of a \patterns command (and an optional list of \hyphenation exceptions), and define it as the next \language for the iniTeX's/LuaTeX processor. So, for instance, for lilipu, the following lilihyph.tex file may be made:
\begingroup
\lefthyphenmin=2 \righthyphenmin=2
\catcode`\'=11 % the glottal stop ' is a consonant!
\patterns{1k 1l 1m 1p 1v 1'}
\endgroup
\endinput

The details of this operation are explained in Appendix H of the TeXbook.
Now, how do you activate the "language" depends on your format and engine: LaTeX and eTeX (the now fashionable formats), on pdf[enc]TeX, XeTeX or LuaTeX (the Unicode aware engines) have slightly different approaches; so your mileage may vary. To add your language hyphenation file For LaTeX and bplain you need to edit the language.dat file and add the line
lilipu lilihyph.tex

for eTeX based formats you need to edit the language.def file
\addlanguage{lilipu}{lilihyph.tex}{}{2}{2}

Then you may use babel's or etex's interface to activate your language settings.
In terms of experimenting, I strongly recommend you to use the Plain format with the LuaTeX engine: LuaTeX is fully Unicode aware, and loads hyphenation patterns directly, without going to reassemble the formats.
Comment: hyphenation is not == language. Where is new characters, where are  specyfic signs. Look at greek language or spanisch 180 rotate ? or ,. in greek
Comment: I know that a language is not a set of hyphenation patterns: language is history, community, and what not... I'm only pointing out to you that for the job of this particular computer program (typeset books) a "language" is reduced to a set of hyphenation patterns, if any, between its glyphs, if the script is phonetic, and if it allows for syllabification.
Comment: The symbols/glyphs for your conlang are defined in the fonts, so you need another program to design and manage the glyphs for your script. Metafont was designed to do it, but it is slightly less useful these days of outline fonts; so perhaps you need something like fontforge. And maybe a good Unicode engine (XeTeX, LuaTeX) may come in handy to let you handle a large set of glyphs for your conlang in print, since TeX/metafont can only handle 256 glyphs at a time.
Comment: not exactly, language is whole, typography too <<>> number, ?! etc
Comment: again: you get all the glyphs from the fonts; setting up the fonts is another issue.


Regularity of an infinite series arising with the heat equation

Question: Let $(t,y)\in(0,\infty)\times\mathbf{R}$, and $\displaystyle f(t,y) \equiv \sum_{k=-\infty}^{\infty}\frac{\exp(-(y-2\pi k)^2/2t)}{\sqrt{2\pi t}}$. This infinite series arises if one attempts to solve the one-dimensional heat equation on $S^1$. I wish to establish the following: $f$ is smooth. I guess one way (and probably the easiest) to do this is, is to show that the series converges uniformly for fixed $(t,y)$ and then to apply Morera's theorem. I wish to apply the Weierstrass M-test, but I did not suceed in finding a series to compare with. Any ideas? Thanks in advance
Comment: Welcome to math.SE! +1 for including background and your work on the problem. I'm afraid I can't help with your question, however.
Comment: Differentiating the $k$th term of the sum however many times in whatever variables can only bring out some polynomial in $k$. The Gaussian factor dominates any polynomial with room to spare. Hence, you have uniform convergence of all derivatives.
Comment: @PavelM Perhaps you could turn that into an answer?
Answer: Let's make $t,y$ complex from the beginning. Specifically, let's shoot for the analyticity on the set $\Omega =\{(t,y)\in\mathbb C^2:  \operatorname{Re}t>0, \ y\in\mathbb C\}$. This open set is the union of compact sets of the form $K=\{(t,y)\in\mathbb C^2: a^{-1}\le \operatorname{Re}t \le |t|\le a, \ |y|\le a\}$ where $a>0$ is positive. For large values of $|k|$, we must estimate the supremum of the modulus of
$$f_k(t,y)=\frac{\exp(-(y-2\pi k)^2/(2t))}{\sqrt{2\pi t}} $$
on $K$. The modulus of the denominator is bounded from below by $a\sqrt{2\pi} $. The modulus of exponential comes from the real part of its argument. We must show that
$$\operatorname{Re}\frac{(y-2\pi k)^2}{2t} $$
is positive and large. Rewrite it as
$$\operatorname{Re}\frac{4\pi^2k^2-4\pi ky+y^2}{2t} = \frac{2\pi^2 \operatorname{Re} t }{|t|^2}k^2 +\operatorname{Re}\frac{4\pi ky+y^2}{2t}\tag{1}$$
where the quadratic term is positive:
$$\frac{2\pi^2 \operatorname{Re} t }{|t|^2}k^2\ge 2\pi^2 a^{-3}k^2 \tag{2}$$
and the remainder (which is $O(k)$) can be estimated roughly:
$$\operatorname{Re}\frac{4\pi ky+y^2}{2t}\ge -\frac{4\pi |k||y|+|y|^2}{2|t|} \ge  -\frac{a}{2}(4\pi a |k|+a^2)\tag{3}$$
Putting (2) and (3) into (1), we get
$$\operatorname{Re}\frac{(y-2\pi k)^2}{2t} \ge 2\pi^2 a^{-3}k^2 -\frac{a}{2}(4\pi a |k|+a^2) \tag{4}$$
To finish, let $M$ be large enough so that $\pi^2 a^{-3}k^2 \ge \frac{a}{2}(4\pi a |k|+a^2)$ whenever $|k|\ge M$. Then for $|k|\ge M$ we have
$$\operatorname{Re}\frac{(y-2\pi k)^2}{2t} \ge \pi^2 a^{-3}k^2$$
and therefore
$$|f_k(t,y)|\le 2\sqrt{2\pi}\exp\left(-\pi^2 a^{-3}k^2\right)$$
Comment: Excellent, exactly what I was looking for. Just some technical detail: I have seen a proof that the series defining the $\vartheta$ function is uniformly convergent, and there the same was shown for $K$ compact (your $K$ is apparently not compact). Does this matter? I mean your proof would work just as well for $|y|\leq c$ instead of $|y|<c$ isn't it? I have edited my question and added the rest of the proof of regularity, is it formally correct? (I'm uncertain about the use of $z, w$ instead of $y, t$) If you elaborate a bit about this, I cannot resist accepting your answer.
Comment: @Karl You were right to be uncertain about the passage to complex numbers.  It does not matter how the variables are named, of course, but to use Morera's theorem we need uniform convergence in the complex domain.  Uniform convergence for real $t,y$ is not enough. For example, the real-analytic functions $g_n(x)=\sqrt{x^2+1/n}$  converge uniformly on $\mathbb R$ to the non-differentiable function $g(x)=|x|$.  I rewrote the answer for complex $t,y$.
Comment: Very nice! Thanks also for your example. I'm sorry if I didn't state this clearly, that I need uniform convergence in $\mathbf{C}$.
Answer: Is the first approximationin 5PM's post correct for all a?
We wish to find an upper bound for $\large |\frac{1}{\sqrt{2\pi t}}| = \large\frac{1}{\sqrt{2\pi}\sqrt{Re(t)}} ≤ \large \frac{\sqrt{a}}{\sqrt{2\pi}} $
Somehow (I don't see why this is true for every $a>0$) 5PM is able to limit $\large|\frac{1}{\sqrt{2\pi t}}| ≤ \large\frac{1}{a\sqrt{2\pi}} ≤ 2\sqrt{2\pi}$


How many standard deviations does a point lie from a 2D Gaussian mean?

Question: I am trying to find a method to calculate how far a point lies from the mean of a 2D Gaussian in terms of standard deviations. I have drawn a diagram to demonstrate my problem.
Diagram of my problem
I know the position of the mean, the position of the point and the 2x2 Covariance matrix of the Gaussian.
I am currently using the Gaussian Distribution function to determine the (z-axis) height of the Gaussian curve at the given point, but a standard deviation measurement in the x/y plane is far more valuable to me.
Answer: What you are looking for is precisely the Mahalanobis distance of an observation.
Comment: This is exactly what I am after, thank you!


How large is the FULL install of TexLive?

Question: How large is a FULL install of TexLive? (2> and what about the RECOMMENDED install of TeXLive and also of MiKTeX?)
Comment: same for MiKTeX. also basic installs of both TeXLive and MiKTeX are around 1.2GB.
Comment: TeXLive Full is on my Linux about 4.5 GB -- not really large for modern hard disks ;-)
Comment: I recommend a full installation because the extra hard drive space is far outweighed by the fact that you won't have trouble with missing packages. Even with MiKTeX, problems can arise when the base installation gets too old and the automatic download feature stops working.
Comment: With `du -sh /usr/local/texlive/2015` I get `5.2G` (I have one backup for each updated package).
Comment: in addition to what @IanThompson said: if internet connection is unavailable, one has everything at hand.
Answer: Reserved disc space for MiKTeX and/or TeX Live:
Basic Installation: takes minimum of 1.2GB
Full Installation: takes minimum of 4.5GB, but usually less than 5.5GB
Recommended Installation reserves 3.2GB.
I recommend a full installation, so all packages are installed, in case one has no internet connection.
Answer: For a full TeXLive:
voss@shania:~> du -h /usr/local/texlive/2016/
[...]
4,9G    /usr/local/texlive/2016/

Answer: The following screenshot of SpaceSniffer provides us with the details visually.

TeXLive 2020 full installation needs about 7.2GB where

Fonts take about 2.9GB
Documentation takes about 2.7GB
Others take about 1.6GB.

Bonus question: Every year it increases by xGB. Find x.
Note
The required space also depends on the Allocation Unit Size (AUS) that you specified when formatting your hard drive. The greater the AUS is set, the faster your hard drive gets exhausted even when you just install several thousands of tiny fonts files. This is my stupid experience when playing with AUS.
Comment: this right there is overleaf's main value proposition. this is insane.
Comment: When will the full installation take 1TB?
Answer: For TeXLive 2018, my computer says 3.9 G by running  du -h /usr/local/texlive/2018/, with 3.7GB taken up by texmf-dist (of which 1.7GB is taken up by the doc folder, and 1.4GB by the fonts folder).
If you enable tlmgr backups feature, this base size will further grow. This is why I am unsure about the above answers. A certain amount of time might have elapsed between when they installed TL on their machines and when this question was answered. The TL binaries themselves are not that big, about 125 MB in my case.
I'd like to add that I have had no problems compiling a large variety of documents with a custom installation of packages so that the whole distribution weighs under 750 MB (726 MB as of today).  When writing/compiling latex documents, I work offline since it helps me to focus better. I am not sure if installing all the fonts is meaningful anyway, and a common selection is sufficient (116 MB for me today).  Even if a specific font is not available on your computer while you are having no internet access, you may simply substitute the exotic font with the basic ones to get to see the typeset PDF. I have ahad no problems with this approach and I can vouch for this approach since I peer-review latex code of all types (as the graduate school's designated LaTeX GTA) in my university.


What is the minimum weight aircraft in which someone can build logged flight time?

Question: What is the minimum weight aircraft in which someone can build logged flight time? Is logging flight hours in an ultralight possible?
Comment: Welcome to aviation.SE! Which country or regulations are you asking about?
Comment: @Pondlife I added a tag. Should my question have it?
Comment: What type of flight time?
Answer: There is no weight limit, requirement, nor restriction for logging time in a logbook. However, there is a requirement to only fly aircraft that are properly certificated, registered, and airworthy regardless of if you log the time or not. Part 103.7 allows ultralights to fly without certification or registration. If you are flying an aircraft not meeting certification, registration, inspection, and airworthiness standards, you are flying illegally unless it meets the weight, horsepower and other criteria of Part 103.1.

§103.7 Certification and registration.
  (a) Notwithstanding any other section pertaining to certification of aircraft or their parts or equipment, ultralight vehicles and their component parts and equipment are not required to meet the airworthiness certification standards specified for aircraft or to have certificates of airworthiness.
(b) Notwithstanding any other section pertaining to airman certification, operators of ultralight vehicles are not required to meet any aeronautical knowledge, age, or experience requirements to operate those vehicles or to have airman or medical certificates.
(c) Notwithstanding any other section pertaining to registration and marking of aircraft, ultralight vehicles are not required to be registered or to bear markings of any type.

Combining this with Part 61.51(j) would prohibit the logging of ultralight experience gained today for the purpose of initial certification or currency.

(j) Aircraft requirements for logging flight time.
  For a person to log flight time, the time must be acquired in an
  aircraft that is identified as an aircraft under §61.5(b), and is—
(1) An aircraft of U.S. registry with either a standard or special airworthiness certificate;
(2) An aircraft of foreign registry with an airworthiness certificate that is approved by the aviation authority of a foreign country that is a Member State to the Convention on International Civil Aviation Organization;
(3) A military aircraft under the direct operational control of the U.S. Armed Forces; or
(4) A public aircraft under the direct operational control of a Federal, State, county, or municipal law enforcement agency, if the flight time was acquired by the pilot while engaged on an official law enforcement flight for a Federal, State, County, or Municipal law enforcement agency.

Furthermore, Part 61.52 does not allow for the logging of ultralight experience gained today for the purpose of initial certification or currency.

§61.52 Use of aeronautical experience obtained in ultralight vehicles.
  (a) Before January 31, 2012, a person may use aeronautical experience obtained in an ultralight vehicle to meet the requirements for the following certificates and ratings issued under this part:
(1) A sport pilot certificate.
(2) A flight instructor certificate with a sport pilot rating;
(3) A private pilot certificate with a weight-shift-control or powered parachute category rating.
(b) Before January 31, 2012, a person may use aeronautical experience obtained in an ultralight vehicle to meet the provisions of §61.69.
(c) A person using aeronautical experience obtained in an ultralight vehicle to meet the requirements for a certificate or rating specified in paragraph (a) of this section or the requirements of paragraph (b) of this section must—
(1) Have been a registered ultralight pilot with an FAA-recognized ultralight organization when that aeronautical experience was obtained;
(2) Document and log that aeronautical experience in accordance with the provisions for logging aeronautical experience specified by an FAA-recognized ultralight organization and in accordance with provisions for logging pilot time in aircraft as specified in §61.51;
(3) Obtain the aeronautical experience in a category and class of vehicle corresponding to the rating or privileges sought; and
(4) Provide the FAA with a certified copy of his or her ultralight pilot records from an FAA-recognized ultralight organization, that—
(i) Document that he or she is a registered ultralight pilot with that FAA-recognized ultralight organization; and
(ii) Indicate that he or she is recognized to operate the category and class of aircraft for which sport pilot privileges are sought.

Weight is not a factor in logging time. And, there is no prohibition against putting things in your logbook that can not be counted for the purposes of initial certification or currency. Although, care should be taken with this. Your logbook is your property. However, your certification gives the FAA the right to inspect your logbook however it chooses. I have co-pilot time logged in a turbine-powered helicopter that I can never count towards anything.
There is also no prohibition against getting an ultralight registered and certificated as airworthy. It might be a lengthy and expensive (and probably improbable) endeavor. But, as soon as you do, it becomes an ultralight no longer according to Part 103.1

§103.1 Applicability.
  This part prescribes rules governing the operation of ultralight vehicles in the United States. For the purposes of this part, an ultralight vehicle is a vehicle that:
(a) Is used or intended to be used for manned operation in the air by a single occupant;
(b) Is used or intended to be used for recreation or sport purposes only;
(c) Does not have any U.S. or foreign airworthiness certificate; and
(d) If unpowered, weighs less than 155 pounds; or
(e) If powered:
(1) Weighs less than 254 pounds empty weight, excluding floats and safety devices which are intended for deployment in a potentially catastrophic situation;
(2) Has a fuel capacity not exceeding 5 U.S. gallons;
(3) Is not capable of more than 55 knots calibrated airspeed at full power in level flight; and
(4) Has a power-off stall speed which does not exceed 24 knots calibrated airspeed.
Comment: Very thorough, very good. Thanks
Comment: `requirement to only fly aircraft that are properly certificated, registered, and airworthy` What do you mean by this? Sounds like you're saying that a licensed pilot is not allowed to fly an ultralight.
Comment: @TomMcW - The entire paragraph from which this quote was taken is in regards to logging time to meet certification and/or currency requirements. So yes, I am saying, today, a licensed pilot can not fly an ultralight to log time **for those purposes**. However, any person can operate an ultralight regardless of whether they have an airman and/or medical certificate. And, since your logbook is your personal property, you can use it however you choose. Just as long as the required information is there upon inspection. Although, I would hazard against extraneous info.
Comment: @TomMcW - Part 61.5(j) Does not allow you to **log** flight time in a Part 103 aircraft for calculating flight time for Part 61 use. Part 103.1 prohibits you from flying an aircraft under Part 103 use if that aircraft is registered and/or certificated as an aircraft category, class, and/or type listed under  Part 61.5(b). As a properly certificated pilot, you can fly whatever you want. Just remember, after January 31, 2012, **what happens in 103, stays in 103.**


What is the memory usage limit on solana's programs?

Question: What is the maximum memory that a solana program can allocate before throwing an out of memory exception, and how is it handled during the program's execution? Is this documented anywhere, like the compute-budget (Is there something like a memory-budget anywhere)?
Also, is there a way to debug the program and see the memory usage?
Answer: The maximum amount of heap space you get in one instruction is 32KB. The current allocator is a naive bump allocator, which does not try to reuse memory, so sometimes you're better off reusing structures.
Also, you get 4096 bytes on each stack frame.
There aren't any syscalls to check heap usage, but you can define a custom heap which logs how much you've used, similar to this example: https://github.com/solana-labs/solana-program-library/blob/master/examples/rust/custom-heap/src/entrypoint.rs
More information at https://docs.solana.com/developing/on-chain-programs/overview#heap


Import Excel to Sharepoint List

Question: I need to import an excel file to Sharepoint list without using manual import (Import to Excel). Instead, I want to import automatically by specifying the path of the Excel sheet or by using any Scheduler. Suggest me...
Comment: Do you mean automatically like all Excel files in Path X should be imported as lists. So when users uploads excel files to that location it should automatically be imported as lists?
Answer: I dont know what do you mean by "manual import" but SharePoint provides you OOB functionality for this, go to view all Site Contents, there you will find the option "Import Spreadsheet", it imports automatically by specifying the path of the Excel, but if you must perform some custom action while importing the data you should consider developing a webpart

Import Excel to Sharepoint List


Copyright on code from public source

Question: Let's imagine consultancy A develops a code for client B that use some free available code from a website so it's a derivative work from the free code (MIT license). Can consultancy A re-use the same derivative work in for client C without copyright infringement due to client B?
Comment: "Freely available" doesn't necessarily mean "free to use", what license is granted with the "free code"?
Comment: MIT license, edited question
Answer: The consultancy can definitely work on the basis of the MIT-licensed code.  However, if the contract between A and B specifies that B gets the copyrights for the developed software and A does not retain rights, then the modifications that A made for B may not be used for C.  If A retains copyright, then there's no problem.

Copyright on code from public source


can I use ffmpeg drawtext filter as a passthrough/identity filter? (and/or performance question)

Question: Background:  I have a script which needs to apply a variable number (from zero to 'a few') drawtext  filters to a base stream, and I'm trying to balance performance and coding/maintenance concerns.  The coding concern here is that I want to be able to use the same base code for each possible filter even though some of them won't be enabled for a given execution of the program.
So... the question: is there an explicit identity or passthrough option for the drawtext filter?  In an ideal world, there would be some option to leave the filter as part of the graph, but tell the code that this particular instance of the drawtext filter should just be an identity filter: said another this is a 'do nothing' or 'passthrough' filter with minimal performance impact.
I could think of a couple ways to possibly do this:

pass a null string as the 'text' value?  I think this would require explicit support within that specific filter?
pass some values using timeline editing that end up making the filter do nothing?  Are there well-known values here (something like "if frame number is less than zero") that are valid but would always evaluate as false?

I'm sure there are many other possibilities - I'm hoping someone has already cracked this particular nut.
Is my thinking correct that most of the compute effort ends up being in the actual filtering and the subsequent encoding, rather than the act of passing the frames into and out of the filter?
(I think this should be here rather that a different stackoverflow sub-site, but if this is better suited for some other place, feel free to either move it or let me know and I'll move it...)
Answer: Yes, method 2 is suitable. Add something like enable=0


Get the angle of an edge

Question: I need to know the angle of an edge using bpy. I need this angle in the x-y plane so if the edge is aligned with the Y axis the angle will be 1.57 radiants (90 degree) and if the edge is aligned with the X axis the angle will be 0. Thanks
Answer: The raw answer is
import bpy
from mathutils import *
from math import *

v1 = Vector([3,2,0])
v2 = Vector([3,2,1])
C = v2-v1

theta = atan2(C[1], C[0])

print(theta)

If you need to be able to compute this from the currently selected edge of a mesh, let me know and I can upgrade the python.
Comment: OK, i was thinking "from the XY plane" , not "in the XY plane", fixed.
Comment: With `v1 = Vector([1,1,0])` and `v2 = Vector([2,2,0])` should give me 0.78 rad (45°) but give me back 0.0. Thanks anyway!
Comment: Thanks , I was also trying with `angle(other, fallback)` but the angle was always absolute. Your is a much better way.

Get the angle of an edge


SharePoint conflict with same username in different domains

Question: We recently ran into a problem in which when we updated a user's photo in mysite, it automatically updated another user's profile with the same photo. On further researching, we found that both users having the same username but they are in different domains. for eg: domain1\user1 and domain2\user1.We have a connection to AD for both domain1 and domain2 and a trust established between the 2 domains.Any fixes for this issue other than changing the username of any of the user?
Comment: I'm not really sure about this, so I won't post it as an answer, but have you tried to go to the User Profile Service applicaiton and there to "Setup My Sites". There is an option "Site Naming Format" where you could choose "Domain and user name (will not have conflicts)" - this is used for the naming of sites but maybe it will also be used for storage of user photos.
Comment: How did you establish trust between two domains. Just eager to learn that :)
Answer: One thing you can do is to set the profile picture user property direction to Import instead of Export, assuming user1 uploads the picture in SharePoint. On Export, the picture overwrites the AD profile picture. In order to change the profile picture (on Import) you have to change the profile picture in your AD (domain1 and domain2).


ATtiny 85 io High Voltage

Question: I've search all over to no success. I tried the data sheet, but couldn't make heads or tails of it. What is the voltage of an output pin of the ATtiny 85 when high? is it just the same as the input voltage a vcc? Also, what is the maximum current output when run at 3.3v?
Answer: This is from the datasheet

The output voltage depends on the current that you sink when the output is set to LOW state

Or the current you source when the output is set to HIGH state
Comment: Please note that the 40mA per pin and 200mA for both Vcc and GND pins are **absolute maximum ratings**. You should design your circuits so that currents are **well below those values** (say 20 mA per pin and 100mA total).
Answer: Table 21.1, on page 161 of the ATTiny25/45/85 datasheet states that the output high voltage is 4.3 volts with a Vcc of 5 volts, and output current of 10 mA.  For 3.3 Vcc, the voltage is 2.5 V at 5 mA. (both voltages are minimums)

ATtiny 85 io High Voltage


Forgot my Gmail Password,alternate id is not accessible and no mobile No

Question: I forgot my gmail password and my alternate id is also not accessible. I haven't provided my mobile number. Now am not able to access mail and facebook account. How can I reset my gmail password. I haven't used my account for about 6 months. I tried the normal rest process but didn't worked. Any help is highly appreciated.
Answer: Unfortunately if none of the recovery options suit your situation, you may never regain access to your account. However, there is still the option of manually verifying your identity.
To begin, go to the google login page. Click "Need Help" then "Forgot password". Enter your email and click continue. If you are asked to enter the last password you remember, click "I don't know". Then click "Verify your identity" which is located under all of the other options. (It is a small link)

You will then be asked multiple questions which you must answer to the best of your ability. If you can provide enough accurate information, you will get your account back.
Hope this helps,
Adam


Freeware to speed up Windows PC

Question: My Windows PC is running slow. Looking for freeware recommendations to fix the problem and keep my 3-year-old PC running smooth.
Comment: Seriously, reinstall Windows from scratch. Avoid to install any bloatware / "browser toolbars" / "tuning software" afterwards. Oh, and consider to exchange the hard disk by an SSD.
Answer: Malwarebytes is the only cleaning software that I would use, nearly all of the other tuning software installs software that actually slows your machine down. But your best bet is a reinstall, maybe with Ubuntu? If you have to stick with installing Windows, once it is installed ensure that you have Windows Automatic Updates active (and that your machine is currently up to date), and use MS Security Essentials as a virus checker.
Or, in addition to the SSD suggestion, maybe your PC just needs more memory? If memory is low then the hard disk will be thrashed swapping page files in and out of memory.
Hope that helps.
Comment: I agree with re-install

Freeware to speed up Windows PC


Find coordinates of point on map

Question: I have scanned map I know it scale and dpi. Is it possible if i know lon-lat cords of some point(X,Y) calculate lon-lat of another point (clicked) on this map? I have read some about georeferencing tools but I'm looking for programming functions to achieve such result.
Comment: What do you mean by programming functions?
Comment: I'mean simply i give `X-Y` mouse position over map and i recive `lat-lon`coordinates
Answer: Due to the warping of the paper on which the map is printed and the scan procedure itself a scanned map will always contain distortions to some extent. That's why methods like georeferencing  have been developed and should be applied in order to add a spatial reference to the map.
Of course you could try to map the pixel coordinates to a location on the scanned map based on the known parameters. But without transforming the map you are very likely to compute coordinates that are far away from the reality. However there are libraries like for example "GeoTools" which provide methods that could help you when looking for a programmatical solution.
Comment: Thanks for you answer! I have little additional question, how can i detect what projection has been used? On my map i dont have any lines just streets and buildings, i know only the scale, it is some kind of administrative map
Comment: If you have an original map document there could/should be some information given somewhere. Otherwise you could maybe try to find out which projection is usually used for other administrative maps of the desired region.

Find coordinates of point on map


Subtitle / Closed caption support in Android

Question: I'm developing an Android app which includes a video component; I'm hoping to provide support for subtitles encoded into the stream but I can't find any references to whether they are supported natively within the Android media player. Does anyone here have any experience with this situation?
Comment: It may be helpful to specify the format of the video and subtitle files which you are handling.
Comment: Indeed! I'm open to suggestion to be honest, as I have some control over what format I'd be using, but ideally it'd be M4V/MP4. I was under the impression that soft subtitles could be encoded into the file/stream so no subtitle files as such, but I'm not a video expert so that could be well wide of the mark!
Answer: Android 4.0.x version and below
In case of Android 4.0 version and below, default Media Player did not support subtitles.
It can be done at application layer (using java code) or using native NDK. More details at this white paper on how to support subtitles in Android
Android 4.1 (Jelly Bean - JB)) Onwards
Android JB version has built in support for internal (present in MP4 files) and SRT external subtitles. More details is available at http://developer.android.com/about/versions/android-4.1.html#Multimedia


log / capture all the queries executed in drupal

Question: I want to log / capture all the queries executed by the drupal?
update, select, insert any query,
is there any hook or what will be the method to do this.
Answer: You want Devel.
It has a lot of helpful tools for Drupal developers, including a helper function to print a summary of all database queries for each page request at the bottom of each page. The summary includes how many times each query was executed on a page (shouldn't run same query multiple times), and how long each query took.
Comment: tried Devel, it is giving the front end queries in debug mod, only select and update to cache table
Answer: Note that Drupal can generate a lot of queries for a single page view. So if you don't want to be doing anything programmatic with the queries then maybe a better option is to just log everything with the MySQL query log.
Comment: mainly want to keep track on insert and update queries


How Do I Use Layer Masks in Photoshop CS5?

Question: I use photoshop cs5 and I want to know how to do a mask layer (i think thats what i want)? i want to edit the foreground separate to the background and I can''t figure out the easiest way to separate the two any help? or point me to a good/easy tutorial?
Comment: Although it is closed, this is one of the most popular on the site in terms of views. We should delete it, migrate it, or improve it and reopen. I'm kind of leaning towards delete, because the actual question (separating the background from the foreground) isn't the same as "how do I use layer masks".
Answer: I think what you're looking for is called "layer mask", which is basically a separately-editable layer, that sets transparency of layer it's connected to.
Googling the term found (a bit older) tutorial at http://photoshoptips.net/2006/07/25/layer-masks/ which seems to cover the thing you've wanted. In short, you:

choose foreground layer
add layer mask to it
draw to the mask. the foreground will be visible in points where the mask is white, a invisible in points where the mask is black.
Answer: If you have CS5, you have a lot of options. There are some pretty advanced new features with Photoshop CS5 and Extended, including Puppet Warp, edge refinement, etc.
If you need simple object isolation, you can use layer masking or the quick selection tool to create a mask that generally outlines your object. The Refine Edge tool, which has been around for a while, but got a big boost in CS5, can help you refine the boundary of your selection, making it more accurate and properly soft and feathered where appropriate. Once you have a general selection around your object, the refine edge tool basically lets you paint along the edge, and photoshop figures out how to separate your object from the background for you. Once you have refined any complex edges, choose OK and you have a nearly perfect soft selection for your object.
A tutorial on edge refinement can be found here:

New in Photoshop CS5 - Cutout and Refine Edge

If you need more than the ability to just isolate a single object in a photo, and actually need to move it around or change its shape, the new Puppet Warp tool is amazing. Using puppet warp, you can set control points on a selection, and move it or change its shape in a non-destructive way. Photoshop uses its new Content Aware fill feature to maintain any "cutout" areas "behind" the selection you are warping. A pretty intriguing tool, which probably has some endless uses. I can't say I've needed it myself yet in my work, however I have messed with it a bit. Its a pretty fun tool.
A turorial on puppet warp can be found here:

New in Photoshop CS5 - Puppet Warp
Quick Tip: Use Puppet Warp in Photoshop CS5 to Tweak Your Images

Finally, there is Content Aware Fill. This one is easy to use, and can be a life saver. If you need to isolate an object for the purpose of removing it from a photograph, the content aware fill makes that ridiculously easy. You don't need to be super precise, and actually some imprecision is useful here. Just make a rough selection around the object you wish to remove, hit delete, and select content-aware fill in the pop-up that appears. Photoshop will analyze your scene, and fill in the hole with generated content that nearly perfectly fits the scene around it. For small removals, or things with complex content, this works beautifully. For larger removals, or removals that have fairly obvious content around them, you may need to spend some additional time making the correct selections. Additionally, it is sometimes useful to remove an object in pieces to get Photoshop to generate the proper fill content. Content Aware Fill is probably my most used Photoshop feature now, as there is almost always something undesirable intruding into my photographs. (That may be something I should work on in-camera, but CAF is so simple and fast, its hard to try and avoid using it. ;))
Tutorial on Content Aware Fill:

New in CS5 - Content Aware Fill
Answer: I have little experience with full fat Photoshop, but this video tutorial looks easy enough to follow.
Video tutorial
Hope this helps.
Comment: Hi John, and welcome. I hope you enjoy your time here. :) One of the goals with stackeexchange sits is to provide concrete information that is hosted here. While we don't have any problem linking other sites, we do ask that any key, relevant information be quoted here, in case the linked site goes offline or permanently disappears. In the case of a video, any key steps or words from the narrator should be quoted. Thanks! :)


Are there rules creating/rewriting/converting classes for Pathfinder?

Question: I was hoping to rewrite the Duskblade for Pathfinder, but I wanted to know if there are specific rules I can find on converting D&D 3.x classes to Pathfinder. Are there?
Comment: Related: [How can I convert 3.5 Generic Classes to Pathfinder?](http://rpg.stackexchange.com/q/8242)
Answer: Yes, but they require quite a lot of experience with the games in question. But there are a depressing number of conversations here. Unfortunately there's a whole book that attempts this discussion -- your mileage may vary. Needing to do this level of homebrew is likely a sign of insufficient system mastery, a love of graven idols, and a need for a better system that supports your requirements.
You also need to have a thorough knowledge of the literature: what do people involved in that system's community think about various aspects of the rules as they relate to mechanisms of your class. Why do they think that way? What are the settled issues? What are the controversial issues? Why are they controversial? All of this discussion is a record of the knowledge and mistakes people have made so you don't have to. Given that you didn't bother to google (or your searches failed to find results) for this in the first place, I would recommend against the practice until you've improved your searching skills. To quote the academic reasoning for lit reviews:

It makes no sense to start a research project without knowing what work has already been done by others. Wouldn't it be embarrassing to unknowingly repeat what others have already done?

There's quite a lot of discussion around current efforts to convert classes, especially with regards to the duskblade. With that said, using and choosing conversions requires a deep system mastery and the expertise that comes of having played a few campaigns with different players to get a sense of how and in what direction conversion choice will break. Layering complexity on top of custom homebrew is severely disrecommended.
Gaining system mastery, and more importantly, expertise in GMing is critical before hacking rules. Once you've run a campaign and have the necessary chops for building characters out to level 20 with an understanding of what choices are made at every level and why, with complex prestige class choices, then start poking your head into the murky world of homebrew classes. Duskblades (unlike binders) are not sufficiently original that they cannot be reproduced.


How to install WINE on linux mint 19.3?

Question: I followed all the instructions, and I got this error:
<code>$ sudo apt install wine-stable

Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 wine-stable : Depends: wine-stable-i386 (= 5.0.2~bionic)
               Depends: wine-stable-amd64 (= 5.0.2~bionic) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
</code>
how can I fix this?
Comment: `sudo dpkg --add-architecture i386`
Answer: Have you tried just wine and not stable version?
<code>sudo apt-get install wine
</code>

How to install WINE on linux mint 19.3?


Is it worth adding identification to trials/demos?

Question: In the world of pirates stealing software, one common technique is to download a trial or demo, patch it and upload this as the stolen version of a piece of software or game. This makes me think: if I sell software one day, it would be possible to set up a custom server, that builds a specific package, personalised to the user, when he downloads a trial. For example, the binary would contain identification numbers and checksums (like a signature using my private key), etc.
This way, if somebody cracks a trail of some software of mine, and uploads that, I could download that, and extract the identification of it. Would that be of some juridical significance to sue the cracker? Compare it to somebody that would buy music on iTunes, and be stupid enough to upload it with his name still in the files. The only difference is that I would try to hide this information, so it's not that easy to spot.
Such information is most likely to remain in the binary, since this has nothing to do with the trail vs full version code in the binary. Or in the least significant bit of the red channel of a PNG image included in the software, for example. A cracker would most likely never notice this, unless he downloads the software multiple times, and bindiffs the packages. If he does that, he could throw try to throw out the information (and optionally a check procedure in the binary that verifies if the data is still there and valid). Then the cracker would have successfully removed the identification information.
I feel like this is an interesting thing to work on and be developing such a thing, but if this isn't going to help me in any way to protect my software, or sue the crackers, then it's probably not worth all the effort.
Comment: I'm voting to close this question because legal assistance is explicitly off-topic per [help/on-topic]
Answer: It depends how much effort you think someone is likely to put into cracking; no system is hacker proof.
A simple check relying on a function that returns success or failure is easy to patch.
If two downloads will only vary in predictable ways then it's relatively simple to mask the original fingerprint.
You need to balance the loss due to piracy against the cost of making it harder.
UPDATE
Depending on the application and connectivity requirements, you may be able to offload a critical and not readily reproducable piece of code to a server that includes license checks.
Answer: Will it help you identify the culprit in a way that holds up in court?
It will depend on jurisdiction, but there are a few complications.
The culprit is not likely to have used his own name in the registration, so what you have to go by is an IP-address and perhaps an email-address. Often that will only get you which local mall the culprit used the wifi to download at.
You might even have the mac-address of the network card in the laptop used for download. But you are not going to get a court order to search all residenses in a 5 miles radius of the mall.
You might be able to help the police build a case by giving them the information, but I doubt it will matter unless you and the culprit are in the same country.


Differences between .insertAdjacentHTML and .innerHTML?

Question: What are differences to consider when choosing between the .insertAdjacentHTML and .innerHTML methods? What are compelling use-cases for each? Which has better performance and in what situations? How does .innerHTML work? Are there other alternatives?
Comment: The two are quite different. The reason to use one over the other depends on the situation.
Answer: There are a few benefits .insertAdjacentHTML has over .innerHTML. The first of which is performance. In a benchmarking test performed, .innerHTML appended slightly over 200 Twitter tweets in five full seconds. insertAdjacentHTML, on the other hand appended nearly 30,000 in the same time-frame.  The more data that needed to be appended, the worse .innerHTML performed. Note however, in this case, data was appended using .innerHTML +=.
Another benefit is control. .insertAdjacentHTML provides you with control over where you want to append data, while `.innerHTML does not.
The final benefit of .insertAdjacentHTML is  it does not corrupt the DOM. Here is how .innerHTML += works.

It gets the value of .innerHTML by serializing the descendants of
element.
It appends the right hand side of += to the string.
It removes the children of element.
It parses the new string that
contains the serialization of the old descendants followed by some
new markup.
Obviously, the last benefit does not really apply in the case of using .innerHTML =.

Other alternatives to .innerHTML are the .insertBefore method, which as its name suggests inserts a node as a child before another node, as well as the .appendChild method which inserts a child node as the last node.
.insertAdjacentHTML is something of a multi-functional tool seeing as it can perform the jobs of .innerHTML, .insertBefore, as well as .appendChild.
Sources: https://hacks.mozilla.org/2011/11/insertadjacenthtml-enables-faster-html-snippet-injection/
Comment: Your question says nothing of using `+=` with `.innerHTML`, so I'm not sure why your answer deals specifically with that situation. It's almost like you didn't read your own question.
Comment: I edited the question, and am currently doing the same for the answer.


Inaccurate distance measurements qgis

Question: I'm trying to reproject a 1/9 arc second DEM from EPSG:4269 to EPSG: 2264.  I also need to DEM to be in feet so I have been using the raster calculator to multiply the original DEM to feet.  When I assign a new projection to the layer and change the CRS of the project the measurement tool is way off.

before converting to feet and changing CRS

After.
Answer: From what I understand about QGIS, changing the CRS on a layer is not the same thing as projecting to a new CRS. If you have a layer with X Y defined by latitude and longitude, and then just change the CRS to a projected coordinate system, the X Y values do not change. Basically it takes those latitude and longitude values and interprets them in terms of units of the projected CRS that you changed to, so everything will be completely messed up like you are seeing.
If you just want measurements in EPSG 2264 you can change the CRS of your map by selecting the button in the lower right of the screen. When selecting your CRS check the box at the top that says "Enable 'on the fly' CRS transformation (OTF)."
This will keep your layer in 4269 like it should be and transform it to 2264 so that your measurements in the map are in ft.
If you really want to change your layer, I think if you do a save as, and select 2264 as the CRS it will transform your layer and save it with the new CRS.

Inaccurate distance measurements qgis


About to be knocked out, all in

Question: I'm about to be knocked out and call all in. There are still 2 players who are able to bet/raise for a side pot, do I immediately have to reveal my hand because I called all in or do I wait until the other players finish their betting? I assume waiting until they finish betting because they could make decisions based on what my hand is even though I'm no longer contributing to the pot(?)
Answer: Yes, you wait. Nobody should never reveal their hand, or any part of it, until no more betting can take place, for exactly the reason you state - it could easily influence the other players' action if they know your hand.

About to be knocked out, all in


How to implement view in browser functionality in newsletter

Question: In my newsletter there is a link "view in browser". I want the same web page url on click of this link from which newsletter is created. Like I have published web pages which name are mysite/email.aspx and mysite/email1.aspx,... Each page has common header component. Header Component has a link name like "view in browser". if I click on email1's newsletter "view in browser" link then it should open this page mysite/email.aspx on web. Now how can I got the same url of web page in email in the href of "view in browser" link. Is there any predefined dwt method for this. Please help.
Comment: possible duplicate of [How to do 'View in Browser' functionality in personalized outbound email ? Any ideas please share](http://tridion.stackexchange.com/questions/2526/how-to-do-view-in-browser-functionality-in-personalized-outbound-email-any-i)
Comment: But in previous question I didn't get the answer that how can I got the current page url of web page in email in the href of "view in browser" link. when we have multiple pages and same header component is used on each page.
Answer: Check Alvin's answer in the post mentioned by Peter: How to do 'View in Browser' functionality in personalized outbound email ? Any ideas please share
You have a couple of options:

you can hardcode the url in the page template html (not ideal) or it can be hardcoded in a newletter page metadata field.
add a C# TBB to:
a. Read the website root from publication metadata for instance http://yourwebsite
b. assemble the page path by getting all parent Structure Groups of the page and combining then into a URL string e.g. http://yousite/sg1/sg2/currentnewletterpage.aspx
Publish the newsletter page. Use Dynamic Linking API inside a proxy page to resolve a PageLink instead of ComponentLink. Pass the right URL parameters to that proxy page e.g. http://yoursite/system/pageresolver.aspx?PageUri=tcm:1-123-64 will redirect to the full url of the published newsletter page.
The link can look like this in your newsletter Html:
View in browser

Create a C# TBB to cleanup the page from any email specifics like merge fields [Name] [Email] etc... to make the page generic as mentioned in the original answer.


explanation of conjugation experiment in bacteria

Question: In this paper (On the expression of a structural gene) I am confused about what is being plotted in Figure 6. The x-axis contains the fraction of radioactive day and y-axis contains the enzyme formation (I assume this is just the concentration of enzyme like Figure 5?). Different point shapes are different times after mating. If so, why are there multiple points of each time? Why are there multiple measurements for say 48 mins past mating? Is the correct interpretation that for each condition, they are showing the fraction of radiolabeled material for each number of day post thaw, like figure 5? It is unclear.
Comment: When I tried to access the pdf you cite (or the host webpage ac.els-cdn.com) I get an Access Denied notification. Could you post a full citation so we can look it up, or post a different link to the pdf?
Comment: @A.Kennard fixed link
Answer: There are three variables being shown here:

The amount of time samples were stored in the freezer to allow $^{32}$P decay (x-axis),
The length of time samples were allowed to grow in a nonradioactive environment before being frozen (points with different symbols), and
The rate of $\beta$-galactosidase production when cells were thawed and grown in the presence of the transcriptional inducer IPTG (y-axis).

Let's break those down a bit more:
The x-axis measures "fraction of $^{32}$P decay." In terms of the experimental protocol, this translates to "length of time left in the freezer." For the $^{32}$P-decay experiments, samples are stored in the freezer for various lengths of time, where metabolic processes, like DNA replication or enzyme production, are shut down or drastically slowed. Although metabolism has been shut down, $^{32}$P can still beta-decay into $^{31}$S (according to Wikipedia), which promotes the breakdown of any DNA containing (formerly) radioactive isotopes. The implication is that the longer you leave samples in the freezer, the more $^{32}$P will decay and the more formerly radioactive DNA will be degraded. So you can read the trend in the x-axis either as "increasing fraction of $^{32}$P decay", "increasing amount of time left in freezer," or "decreasing fraction of intact $z^+$ DNA." The different points corresponding to, say, "48 minutes past mating" correspond to samples that were frozen down 48 minutes past mating but kept in the freezer for different lengths of time.
The y-axis measures "percent survival of enzyme-forming capacity." I think that it's safe to interpret this as the rate of $\beta$-galactosidase production relative to the rate with no $^{32}$P-decay. In other words, if you plot $\beta$-galactosidase production over time (as in Figure 5) for different conditions, you'll measure a slope, the rate of enzyme production. If you normalize all these rates from different conditions by the rate when there was no radioactivity (and thus no degradation of $z^+$ DNA in the freezer), you'll get the values plotted on the y-axis.
The final interpretation of this plot is that the $\beta$-galactosidase production rate is sensitive to the loss of the introduced $z^+$ DNA when the loss occurs soon after mating, but if cells are allowed to grow enough to divide once or twice before DNA degradation, then the loss of the original conjugated $z^+$ DNA does not affect the $\beta$-galactosidase production rate. This data is consistent with the idea that the DNA form of a gene is constantly required for sustained $\beta$-galactosidase production, and after several rounds of division the $z^+$ DNA has been replicated and is no longer radioactive and prone to degradation.
There's a lot of data in this plot (ah, the elegance of 1960s molecular biology!) so it can take a while to digest. Hope this helps!
Comment: Great answer - was working on an answer myself, but no need for it now. It's worth adding a historical note that this paper, and especially an earlier (1959) paper from Pardee, Jacob & Monod, formed the basis of the idea of mRNA - an unstable intermediate between gene (DNA) and protein. And this in turn led to the experiments of Nirenberg that are touched upon in [this question](http://biology.stackexchange.com/questions/13430/proportion-of-amino-acids-from-a-random-polymer-of-u-and-c)


how to send database query result in json and display results in javascript?

Question: Can any one give me example or reference for converting mysql database query results in to json object and send it to javascript file then parse the json and display results in javascript file using jquery?
Thanks.
Answer: If you are using PHP, you can use json_encode to convert a PHP array to JSON.  Usually mysql results are given in arrays.
Using jQuery, you can give the $.ajax method a dataType of 'json', so it will parse the JSON into a JavaScript array for you. (I'm assuming you are using AJAX.)
Or, you can save load the PHP variable in a JS one by doing this:
var sqlResults = <?=$results?>;

I hope this helps.


I want to host the same website content on different domains

Question: I need to find out how I can host different domains which will have the same content. I want users to be able to choose their country and based on that decide which domain to load. How do I do this without having to duplicate content? thanks
Comment: Can you tell us a little more about why you want do do that. It's bad for SEO as @vinoth points out, and does not seem to be reasonable to me either. Or, would you provide translated content on your different domains?
Answer: You just need to:

register the international domains;
point them to your provider;
setup your provider nameservers to server all that domains;
use HTTP_HOST environment variable in your code to detect from which domain the user is accessing, if that matters.
Answer: Your making your content spam by your own work. Now google looking on big eye about duplicate content. Recently they have changed their algorithm which includes panda
Answer: What you are trying to do is called Duplicate Content and it's generally bad for SEO, but in some cases this is unavoidable.
To circumvent the duplicate content issue for same language content in different countries, you could set the hreflang with rel="alternate" attributes to tell the search engines which language content belongs where:
Scenario:
Website A offers content for France, incl. French content and English content.
Website B offers content for Swiss, incl. French content and English content.
Now, both websites have the exact same content offered, just for different markets. With the hreflang and rel=alternate you could tell Google that Website A should be offered only in language_Country fr_FR and Website B fr_CH.
More information here and here
Answer: I'm not sure what you mean here.
Are you wanting identical content on different TLD's that are specific to countries? ie .co.uk for UK, .com for US, .ie for Italy
Or are you wanting one domain/TLD and to serve up different content based on the users country of origin?
If so you can use a variety of different Geolocation techniques. IP2Location is one company that offers a fairly robust solution.
Comment: I want your first option quote:"Are you wanting identical content on different TLD's that are specific to countries? ie .co.uk for UK, .com for US, .ie for Italy". thanks Digital Essence
Answer: you can make one code which detects from where the person is coming.
and then redirect according to the location to that domain.
and all the domains should be pointed to the same server where you host your files.
so suppose the person comes to yoursite.com and he's coming from UK, then your code should redirect him to yoursite.co.uk's homepage. you'll need IP detection to check the place from where the person is visiting.
Answer: First make sure all the domains are pointing to the same server. Then set up a Virtual Host for each domain pointing to the same directory on the server, where your site content is located. If all other settings will be the same for all the domains you can define them all as part of the same Virtual Host entry in your web servers configuration.
If you are using Cpanel or something similar, just make sure each domain is pointing to the same directory.
Alternatively, you could do this by modifying your name servers with CNAMEs.


Create non-animated, realistic film noise w/ scratches procedurally

Question: I know I'd probably use a combination of Noise Textures, but I have no idea how I could make it look realistic with varying combinations of random dots, scratch- and hair particles etc. I could only find some explanations on how to achieve standard film grain, nothing too detailed.
Comment: https://blender.stackexchange.com/questions/84546 https://blender.stackexchange.com/questions/123139 https://blender.stackexchange.com/questions/68863
Answer: You could do something like this.

The graph is comprised of mainly 2 parts - the "spots" and the "lines". Similar to what you were thinking, instead of Noise Textures, I used the distance output of Voronai Textures to make the "grain dots". I used varying levels of scale and randomness in addition to clamping the values with ColorRamps and using them to add a slight mustard-like hue (to match your image). I made 2 "fields" - one slightly dimmer than the other, and combined them using a Noise texture as a mix factor, so the end result would be a "patchy" combination of the two.

For the lines, I used a series of Wave Textures, offsetting some with Mapping Nodes and subtracting their values from each other, until I was left with some randomly spaced white lines that I then further darkened with another Noise Texture (so they aren't so evenly bright).

The last step, I used a Noise texture, heavily clamped to make the small white dots that are lightly "speckled"  around the image.

Finally I put them all together. I used an Emission Shader, as it makes sense that this is being emitted from a screen, and I ran the output through a HSV node first for finer control over the color and the brightness.

I'll post the file here, so you don't have to take the time to rebuild the graph yourself if you want to play with it.
File is here -
Comment: I played around with your file and there are a lot of amazing possibilities. The reason I asked the question was because it's really hard to find free CC0 film grain overlay textures for programs like Photoshop in high resolution. To make the render look even more realistic I tried to 1) add hair/scratch particles by copying your White Dots group and 2) vertical lines by copying the Lines nodes and rotating them, but I'm new to Blender and not entirely satisfied with the result – I feel like the outcome would be perfect if you would give it a shot. Let us know, this is an amazing setup!
Comment: Yeah, I didn't go too detailed or add the vertical lines just because I was making a quick demo. However, I'm glad you found it helpful and would be happy to help you further. I'm working on a couple things right at the moment, but when I have a bit of time, I'll update the file with more detail. I'll post it here when I'm done.
Answer: I can pretty quickly get a result like this using the compositor:

You can create textures using the Texture Properties Panel.  I identified three main features of your image to reproduce: a bed of noise, larger white flecks, and horizontal bands, trying as much as I can to avoid complete continuity.
You can recreate these features with a noise texture:

A musgrave texture:

Note that musgrave returns a range of -1 to 1, so it's easier to ramp it down to small black flecks and then invert in the compositor.
And this is what I actually used for the bands, but we're going to heavily modify this in the compositor.

You can choose these textures in the compositor from a Texture node, and mix them into your final image.  Here's what my node group looks like:

Note that we're stretching and squeezing the distorted noise texture quite a lot, and then applying a pretty harsh color ramp to it.  This gives us a more pleasing banding effect that doesn't have a hard cutoff and doesn't span the entire image.
I encourage you to experiment with more layers and colors to create the exact effect you want.


Installing Kubernetes on Ubuntu 18.04 LTS (with Docker) - fails on init

Question: I am attempting to install Kubernetes on VMs running Ubuntu 10.04 LTS, and running into a problem when trying to initialise the system, the kubeadm init command results in failure (full log below).
VM: 2 CPUs, 512mb RAM, 100 gig disk, running under VMWare ESXi6.
OS: Ubuntu 18.04 LTS server install, fully updated via apt update and apt upgrade before beginning the Docker and Kubernetes installs.
Docker installed as per instructions here, install completes with no errors:  https://kubernetes.io/docs/setup/production-environment/container-runtimes/#docker
Kubernetes installed as per instructions here, except for the Docker section (as following those instructions produces a PreFlight error re systemd/cgroupfs): https://vitux.com/install-and-deploy-kubernetes-on-ubuntu/
All installation appears to proceed smoothly with no errors reported, however attempting to start Kubernetes then fails, as shown in the log below.
I am entirely new to both Docker and Kubernetes though I get the main concepts and have experimented with the on-line tutorials on kubernetes.io, but until I can get a working system installed I'm unable to progress further. At the point at which kubeadm attempts to start the cluster, everything hangs for the four minutes, and then exits with the timeout as shown below.
root@k8s-master-dev:~# sudo kubeadm init --pod-network-cidr=10.244.0.0/16
[init] Using Kubernetes version: v1.15.3
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-master-dev kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.24.0.100]
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-master-dev localhost] and IPs [10.24.0.100 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master-dev localhost] and IPs [10.24.0.100 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[kubelet-check] Initial timeout of 40s passed.

Unfortunately, an error has occurred:
        timed out waiting for the condition

This error is likely caused by:
        - The kubelet is not running
        - The kubelet is unhealthy due to a misconfiguration of the node in some way (required cgroups disabled)

If you are on a systemd-powered system, you can try to troubleshoot the error with the following commands:
        - 'systemctl status kubelet'
        - 'journalctl -xeu kubelet'

Additionally, a control plane component may have crashed or exited when started by the container runtime.
To troubleshoot, list all containers using your preferred container runtimes CLI, e.g. docker.
Here is one example how you may list all Kubernetes containers running in docker:
        - 'docker ps -a | grep kube | grep -v pause'
        Once you have found the failing container, you can inspect its logs with:
        - 'docker logs CONTAINERID'
error execution phase wait-control-plane: couldn't initialize a Kubernetes cluster

I've had a look at both the log journal data and the docker logs but other than lots of timeouts, can't see anything that explains the actual error.  Can anyone advise where I should be looking, and what's most likely to be the cause of the problem?
Things already tried: Removing all IPTables rules and setting defaults to "accept".
Running with Docker install as per the vitux.com instructions (gives a PreFlight warning but no errors, but same timeout on attempting to init Kubernetes).
Update: Following from @Crou's comment, here is what happens now if I try just 'kubeadm init' as root:
root@k8s-master-dev:~# uptime
 16:34:49 up  7:23,  3 users,  load average: 10.55, 16.77, 19.31
root@k8s-master-dev:~# kubeadm init
[init] Using Kubernetes version: v1.15.3
[preflight] Running pre-flight checks
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR Port-6443]: Port 6443 is in use
        [ERROR Port-10251]: Port 10251 is in use
        [ERROR Port-10252]: Port 10252 is in use
        [ERROR FileAvailable--etc-kubernetes-manifests-kube-apiserver.yaml]: /etc/kubernetes/manifests/kube-apiserver.yaml already exists
        [ERROR FileAvailable--etc-kubernetes-manifests-kube-controller-manager.yaml]: /etc/kubernetes/manifests/kube-controller-manager.yaml already exists
        [ERROR FileAvailable--etc-kubernetes-manifests-kube-scheduler.yaml]: /etc/kubernetes/manifests/kube-scheduler.yaml already exists
        [ERROR FileAvailable--etc-kubernetes-manifests-etcd.yaml]: /etc/kubernetes/manifests/etcd.yaml already exists
        [ERROR Port-10250]: Port 10250 is in use
        [ERROR Port-2379]: Port 2379 is in use
        [ERROR Port-2380]: Port 2380 is in use
        [ERROR DirAvailable--var-lib-etcd]: /var/lib/etcd is not empty
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`

Re the very high load shown bu uptime, that starts as soon as the init is first attempted and load remains very high unless a kibeadm reset is done to clear everything down.
Comment: What is the status of kubelet? Try doing plain `kubeadm init` as root.
Comment: @Crou Full output too long for a comment here but it throws lots of fatal errors about ports in use and files already existing.  It's as if it is mostly running - but it can't be connected to or operated in any way.
Comment: You need to check what is causing the load when you do `kubectl init` after you clear everything by `kubectl reset`. It looks like it gets stuck somewhere.
Answer: Further experimentation: In addition to VMware ESXi hypervisors we also run XenServer hypervisors on identical hardware platforms.  I attempted an identical install on a VM on one of the Xen blades, however it proved impossible to install Ubuntu at all, install failed at the "Installing the kernel" phase.  I tried two separate installs, both failed at exactly the same place.  The VM spec was same as under ESXi, 2 cores, 512MB memory, 100 gig hard disk.
Solution: We finally solved the problem by dispensing with VMs and installing Ubuntu 18.04 directly on the hardware, no hypervisors or VMs involved, then adding Docker and Kubernetes, and this time the kubeadm init command completed correctly with the expected messages appearing.  The spec of the blade we installed on is 2 x hexacore Xeon processors and 48 gig of ram, with a 1TB hard disk.


How to play a crochet (quarter note) rest in a minuet by Bach

Question:
What is purpose of the crochet (quarter note) rest that is shown between treble and bass clef in the fourth measure, and how do I play it?
Answer: This answer is coming from my experience as a former chorister but I think it would still apply here...
Think about a tenor and bass singer in a four-piece SATB choir. If the lower singers shared a clef, the bass singer might sing the notes with the staves pointing down, and the tenor would then sing the notes with the staves pointing up, in order to differentiate which notes should be sung by each part. If you think about the bass clef as written in two parts, it is saying that in 3/4 the rhythm for bars 5 & 6 for the two parts is:
<code>[beat in bar]: |     1      |      2     |     3      |
[tenor]:       |   {rest}   |         {minim}         |
[bass]:        |         {minim}         | {crotchet} |
</code>
It is a way of singling out melodies or distinct parts without having messy held notes all over the place, and is common in SATB transcriptions and also in fingerstyle guitar transcriptions.
Answer: That part is written effectively in three voices. The bass clef has stems up and down. The up stems, the D and E notes, are preceded by the crotchet rests, partly to put the notes into their correct timing, on beats 2 and 3.
When you play the piece, actually there's nothing to do, as you will 'play' the rests by not playing anything until you play the notes with up stems.


How to reinstall Ubuntu with a fresh start without removing files?

Question: I want to have a fresh Ubuntu start, with everything being default. But I don't want to lose files, I have lots of movies, documents etc. I don't want to remove, and I can't backup them, because they take too much space. Is it possible?
Comment: this probably isn't what you are after but i just install the fresh ubuntu onto a new partition.My older ubuntu partitions are easily mounted and music/movies/files easily retrieved
Answer: To avoid this problem in future, consider installing Ubuntu with a / partition and a /home partition. Then, when you upgrade, you can either overwrite / or make a new / partition for your new Ubuntu, leaving the /home partition intact to be accessed from whichever version of Ubuntu you choose to fire up from the grub menu. I have used this strategy for all my Ubuntu installs on several machines, and it has enabled me to upgrade relatively painlessly on numerous occasions without losing personal data files.
But, I always back things up first in any case. It really is worth getting a large usb external disk to back up your /home partition or directory. You never know when your hard drive is going to go ...
Answer: When installing Ubuntu you can use the "side by side" option when you are at the partitioning phase of the installation.
It will keep your existing ubuntu and install you a new one.
The side effect is that your old ubuntu will be in another partition of your hard drive. You'll have to :

Resize this partition during installation in order to give space to your new ubuntu
Clean grub from the old Ubuntu
Clean the other partition (containing your old ubuntu and movies) from the unused system files.
Answer: You can use the Ubuntu DVD to reinstall it then you can create a new account or - better - remove all hidden configuration files. To do this open the File manager, press CTRL + H then delete .config. You can also delete other hidden files and folders if you need to.
Answer: I concur to Bobble's suggestion.
Before you reinstall Ubuntu, run the "Try Ubuntu" option, and perform the following steps. I don't recommend to do this to an unexperienced user without a backup! If everything goes as planned, you won't need one, but else – who knows? Borrow a sufficiently large external drive from a friend, if you can't afford one. It is always a good idea to have a backup anyway.

Mount your old partition.
Delete everything except your home directory. You should now have enough space for a new installation.
Assuming a default setup, delete everything in your home directory starting with a dot except .local, .ecryptfs, .Private, i. e.:
find /media/old-partition/home/mrSuperEvening -mindepth 1 -maxdepth 1 -name .\* ! -name .local ! -name .ecryptfs ! -name .Private -exec rm -rf -- \{\} +

You have now deleted all user configuration. Skip this, if you still need it.
Unmount the old partition.
Resize it with GParted so that enough free space remains on the drive for a new Ubuntu installation.
Reinstall Ubuntu on a new partition in the free space and use the old partition as /home.
Your old data should now reside in /home/home/mrSuperEvening and you can move it wherever you like, i. e. to /home/mrSuperEvening.