Does WSProxy Calls consume SFMC API limits?

Question: We have a use-case where we have to find out all the Data extensions present in a Business unit. We can achieve this by using the WSProxy Retrieve option or SSJS RetrieveRequest approach. As the performance is better in WSPRoxy so we are leaning towards using WSProxy but the only concern that we have is does WSProxy calls consume SFMC APIs? If it does then we have to go with the SSJS approach as we do not want to consume SFMC API limits for this implementation.
Answer: As far as I know, the answer is 'No'. I have done a similar solution for 30 business units and also fetching the count of rows in the Data Extensions using the undocumented REST API. The automation was running on daily basis along with other BAU Operations. We never hit any limits or faced any issues. So, you should not have any problem. The only thing to consider is the timeout for SSJS activity if you plan to do this via Automation Studio. We split the automation in 5 activities having processed 6 BUs at a time.
Comment: No, and as I mentioned, I don't think there are API limits in this regard
Comment: Thanks Swati for the suggestions. Have you found any documentation on this topic in any Salesforce Help portals regarding if the WSProxy or SSJS Retrieve calls consume SFMC APIs or not?


Access 2010 Optimizing a bloated query

Question: I have to have this query produce a monthly average availability for a selection of equipment. The query looks pretty ugly and rather bloated and I'm wondering if there's something I can do to make it better.
Right now I have an Expression column representing each month. In each month, take January for example, I need to check if the maintenance period occurred within the month, started before the month but ended during, started during the month but ended outside, completely encapsulates the month (if Jan 2012, then started maintenance Dec 2011 ended Feb 2012),  or not count it because it was fully operational throughout the month.
So as you can see checking these 4 cases and doing calculations afterwards really bloats up one month, let alone 12! So I'm just looking for a suggestion if there's something more I can be doing. I'm not afraid of some RnD if someone has articles they can point me towards. If this approach is not overly bad I don't mind, I would just like to do better if its possible.
Thanks in advanced!
Comment: If you have not got too many records, this could be a case for a User Defined Function.
Answer: can't you just do a simple crosstab query in MS Access?

Access 2010 Optimizing a bloated query


Spellchecker in Lyx 2.1.4 Does Not Work

Question: I just upgraded to Lyx 2.1.4 from Lyx 2.1.3 and the spellchecker does not work -- it asks if I want to start from the beginning and then closes like it found no errors. I am using Windows 7 with a clean default install of Lyx. Any ideas on how to get the spellchecker working again?
Comment: Note that I tried the fix suggested for "LyX Install Not Recognizing Installed Spellcheck Dictionaries" and it did not work.
Comment: As an interim fix I rolled back to Lyx 2.1.3, which works as expected.
Comment: Are your preferences the same? You might try taking the preferences file from 2.1.3 that works for you and using it with 2.1.4 to see if that helps. To find your pfreferences file, go to Help About. It is in the user dir. On Ubuntu this is in `~/.lyx` but I don't know about Windows.
Answer: I had a similar problem which I managed to fix by going into Document -> Settings -> Language and then changing the default, which was English, to English (UK).
Answer: I think I found the problem. First point the path of hunspell to your equivalent folder:
C:\Program Files (x86)\LyX 2.1\Resources\dicts
Then, it is an incorrect or corrupted en_US.aff/dic files. I downloaded another version from hunspell project:
http://sourceforge.net/projects/hunspell/files/Spelling%20dictionaries/en_US/
and overwrite ir in the dicts folder, that worked for me.
Comment: Worked for me. I had to replace the files. (You also have to remember to 'reconfigure' from the tools menu.
Comment: I tried all other comments (paths were empty) but in the end also needed to reinstall the dictionary files from the location mentioned.  I was surprised by this.  Does the LyX installation have corrupted files in it?
Answer: The UK solution works, but if you want any other language like US English, this is the way to fix it:
First, find the hunspell directory with all the dictionary (dic and aff) files in it. For me, it was "C:\Program Files (x86)\MiKTeX 2.9\hunspell\dicts"
Next, point Tools > Preferences > Paths > Hunspell Dictionaries text box to this directory.
Lastly, restart Lyx.
Source: LyX Install Not Recognizing Installed Spellcheck Dictionaries
Comment: I tried that before I posted the question and it did not work for me.
Comment: I think you need to reconfigure
Answer: I was able to find a solution to this problem. Copy your dic and aff files from where they are now (C:\Program Files (x86)\LyX 2.1\Resources\dicts, usually), to a new folder, C:\dicts (or similar), and then change the path in lyx accordingly, and reconfigure lyx.
I don't know exactly why this works though.
Comment: This did not work for me.

Spellchecker in Lyx 2.1.4 Does Not Work


How to tell $i$ from $-i$?

Question: Suppose now we are trying to explain to students who do not know complex numbers, how do we distinguish $i$ and $-i$ to them? They will object that they both squared to $-1$ and thus they are indistinguishable. Is there a way of explaining this in an elementary way without go into introductory things in complex analysis?
Comment: Roughly speaking you can't. The map that takes $a+bi$ to $a-bi$ is an automorphism of $\mathbb{C}$.
Comment: $-1$ and $1$ both square to $1.$ Does this means they're indistinguishable?
Comment: @J.D. Ah - but there is no automorphism taking 1 to -1.
Comment: First, $1$ and $-1$ are distinguishable because $1$ is its *own* square, while $-1$ isn't. From this, you also can easily distinguish $2$ and $-2$ because $2=1+1$ and $-2=(-1)+(-1)$. Indeed, it's not hard to extend this to $\mathbb{Z}$, and then to $\mathbb{Q}$. Finally you get all of $\mathbb{R}$ by considering sequences of rational numbers converging to that real number. Thus for each real number $r$ you can uniquely determine which one of $r$ and $-r$ is positive and which one negative. But this doesn't work for $i$.
Comment: Does the relationship between $i$ and $-i$ the same with "left" and "right",or "clockwise" and "anticlockwise"?
Comment: They have different arguments, just show them on an Argand diagram?
Comment: @bigeast: Yes. See my answer for more details.
Comment: See also http://math.ucr.edu/home/baez/week201.html
Comment: yeah, I am expecting an answer related to Galois group.
Comment: It's also worth pointing out that $2$ and $-2$ both have $4$ as their square, so by the given argument, $2$ and $-2$ are indistinguishable.
Comment: These sound like high school students, right?
Comment: Square of  6 and $-6$ are 36 but both are not same.
Comment: @celtschk You can't distinguish positive and negative irrationals in $\mathbb{C}$ using only the algebraic structure, since there is an automorphism of $\mathbb{C}$ swapping $\sqrt{2}$ and $-\sqrt{2}$. Indeed, the real numbers are not definable in $\mathbb{C}$ using only the field structure, since there is an automorphism taking $\sqrt[3]{2}$ to one of the other complex roots.
Comment: That's an awfully sophisticated student...
Comment: @JDH: I didn't claim anywhere that you can. The step from $\mathbb Q$ to $\mathbb R$ contains a non-algebraic operation (limits of sequences).
Answer: Simple: there are two distinct values whose square is $-1$, so you choose one of them and call it $i$. The other one, then, is $-i$. It doesn't matter which of them you choose, just as it doesn't matter which direction in space you call $x$.
Comment: With the proviso that, once you've made your decision, you must stick with it thereafter.
Comment: Upvoted because OP asked for "explaining this in an elementary way."
Comment: There are two distinct values whose square is +1, but it *does* matter which we call 1, and which we call −1.
Comment: @I.J.Kennedy: That's true, but what is your point?
Answer: If you construct $\Bbb C$ as $\Bbb R[X]/(X^2+1)$ the roots are indistinguishable. You just choose one and identify it with the point $(0,1)$ in the Gauss-Argand plane. That chosen one will be $i$.
If, on the other hand you construct $\Bbb C$ as the set of pairs $(a,b)\in\Bbb R^2$ with suitable addition and multiplication, then $\pm i=(0,\pm1)$.
The two constructions are of course isomorphic but not canonically isomorphic, due to the arbitrarity of the choice of a root which is the effect of existence of a trivial $\Bbb R$-automorphism, namely complex conjugation.
Comment: If you construct $\mathbb{C}$ as $\mathbb{R}[X]/(X^2+1)$, then $i$ is the coset $X+(X^2+1) \mathbb{R}[X]$ and $-i$ is the coset $-X+(X^2+1) \mathbb{R}[X]$.
Comment: "If you construct $\,\Bbb C\,$  as $\,\Bbb R[X]/(X 2 +1)\,$  the roots are indistinguishable" ---This isn't right and David Speyer already gave a reason, but we could also argue that $\,i\,,\,-i\,$ would be indistinguishable iff, in some algebraic structure, we'd have $\,i=-i\Longrightarrow 2i=0\,$ , and since the construction $\,\Bbb R[x]/(x^2+1)\,$ is a field of characteristic $\,\neq 2\,$ the above is impossible.
Comment: @NilsMatthes  : No, I mean $\Bbb R$-automorphism! If $F\subset L$ are fields, a $F$-automorphism (of $L$) is an automorphism that leaves the elements of $F$ fixed.
Comment: If you construct $\mathbb{C}$ as pairs, then there's initially no $i$,. but only the pairs $(0,1)$ and $(0,-1)$. Therefore you *still* have the freedom which of them you call $i$.
Comment: You mean non-trivial $\mathbb{C}$-automorphism instead of trivial $\mathbb{R}$-automorphism, right? Or do you mean one which is trivial on $\mathbb{R}$, though non-trivial on $\mathbb{C}$?
Comment: Ah I see, somehow I forgot that term. Thank you.
Answer: If you construct $\mathbb{C}$ purely algebraically then there is no distinction until you've chosen what $i$ is, and then the distinction is made by the observation that if $x=i$ is one solution to $x^2=-1$ then $x=-i$ is the other.
This is because we construct $\mathbb{C}$ algebraically as the field $\mathbb{R}(i)$ obtained by adjoining $i$ to $\mathbb{R}$, where $i$ is an abstract root of the polynomial $x^2+1$. But once you've done this, you can declare that $i$ is the point on the Argand diagram lying at unit length 'above' $0$, and this distinguishes it from $-i$. As André Nicolas says in the comments, if you'd chosen $-i$ instead of $i$ then it doesn't matter, since the (unique!) map fixing $\mathbb{R}$ and sending $i \mapsto -i$ is a $\mathbb{R}$-automorphism of $\mathbb{C}$. (Intuitively: choosing the other root changes nothing except labelling.)
In more human terms, you say $i$ is 'something' which squares to give $-1$, and then $-i$ is 'the other thing' which does the same.
We can then make the translation to the Argand diagram by identifying this new field $\mathbb{C}=\mathbb{R}(i)$ with the plane $\mathbb{R}^2$ by using the following correspondence:
$$\mathbb{C} \ni a+bi \leftrightarrow (a,b) \in \mathbb{R}^2$$
with operations
$$(a,b)+(c,d)=(a+c,b+d)$$
$$(a,b)\cdot(c,d)=(ac-bd, ad+bc)$$
Answer: It doesn't matter which one you call $i$; whichever it is, the other one is called $-i$.
I suspect it's not necessary to say more than that.  And in a way, to say much more in answer to that question might amount to making the answer seem more complicated than it really is.  That doesn't mean you shouldn't say more after saying that; e.g. that the field $\mathbb{C}$ has exactly one automorphism that's not hideously ill-behaved, etc.
Answer: First off, you don't need to know anything about complex analysis in order to understand this. Complex analysis refers to doing calculus with complex numbers, but this is just a question about the basic complex-number system itself.
By way of analogy, let's think for a moment about the way the ancient Greeks conceived of ordinary numbers. Euclid's Elements is actually not just about what is taught today as geometry; it's full of material that today would be considered to be algebra and number theory. For example, what we would represent as multiplication $xy$, Euclid would represent as the area of a rectangle with sides of certain lengths. An identity like $x(y+z)=xy+xz$ would be represented as cutting a rectangle into two smaller rectangles. In Euclid's system, there is no such thing as the real number system, and in fact there is not even a number 1. If I say I'm 6 feet tall, in Euclid's language we would say that we have two different line segments, and their ratio is 6. The small one is arbitrarily chosen as the unit of measurement. But the choice of the unit segment is completely arbitrary, and it can be different if you finish one calculation and start another one.
Similarly, it's completely arbitrary how to label $i$ versus $-i$. For example, a typical application of complex numbers is to describe oscillations. Suppose two cars' windshield wipers are both running. They have the same frequency, say 1 Hz, but they're out of phase with one another by 90 degrees. We can represent the two oscillations as complex numbers whose magnitudes represent the frequency and whose arguments represent the phase. The magnitudes both have to be 1, but it's completely arbitrary whether we use a bigger argument to represent an oscillation with a leading phase, or a lagging one. We have to make an arbitrary choice. There is nothing obliging us to be consistent about this choice from one calculation to the next.
So just as Euclid's system "doesn't care" which length we consider a unit, the complex number system "doesn't care" which root of -1 we call $i$ and which $-i$.
Comment: _area of a triangle_ -- did you mean _rectangle_?
Comment: @sarnold: Thanks, fixed.
Answer: This question relates directly to issues that are often discussed in the philosophy of mathematics.
According to one of the standard accounts of structuralism, what mathematical objects are at bottom are the structural roles that they play within a mathematical system. One might define the equivalence relation whereby element $a$ in structure $A$ is equivalent to element $b$ in structure $B$ exactly when there is an isomorphism of $A$ to $B$ taking $a$ to $b$. This results in what I have called the isomorphism orbit of the object $a$ in $A$.

According to some accounts of the philosophy of abstract structuralism, what a mathematical object is, is the structural role that it plays in abstract mathematical structures.
The problem for this view arises with nonrigid mathematical structures such as the complex field $\newcommand\C{\mathbb{C}}\C$.
Here is how I describe the situation is my book, Lectures on the Philosopy of Mathematics (MIT Press)

Although one conventionally describes $i$ as "the square root of negative one," nevertheless one might reply to this, ``Which one?'' in light of the fact that $\newcommand\unaryminus{-}\unaryminus i$ also is such a root:
$$(\unaryminus i)^2=(\unaryminus 1\cdot i)^2=(\unaryminus 1)^2i^2=i^2=\unaryminus 1.$$
Indeed, the complex numbers admit an automorphism, an isomorphism of themselves with themselves, induced by swapping $i$ with $\unaryminus i$---namely, complex conjugation:
$$z=a+bi\qquad\mapsto\qquad\bar z= a-bi.$$
The conjugation map preserves the field structure, since $\overline{y+z}=\bar y+\bar z$ and $\overline{y\cdot z}=\bar y\cdot\bar z$, and therefore the complex field is not a rigid mathematical structure. Since conjugation swaps $i$ and $\unaryminus i$, it follows that $i$ can have no structural property in the complex numbers that $\unaryminus i$ does not also have. So there can be no principled, structuralist reason to pick one of them over the other. Is this a problem for structuralism? It does seem to be a problem for singular terms, since how do we know that the $i$ appearing in my calculations this week is the same number as what will appear in your calculations next week? Perhaps my $i$ is your $\unaryminus i$, and we do not even realize it.

If one wants to understand mathematical objects as abstract positions within a structure, as in abstract structuralism, then one must grapple with the fact that in light of the conjugation automorphism, the numbers $i$ and $\unaryminus i$ play exactly the same roles in this structure (see Shapiro, 2012). The numbers $i$ and $\unaryminus i$ have the same isomorphism orbit with respect to the complex field, and so in this sense, although distinct, they each play exactly the same structural role in $\C$. This would seem to undermine the idea that mathematical objects are abstract positions in a structure, since we want to regard these as distinct complex numbers.
The point is that one cannot understand the mathematical objects as identical to the structural roles that they play within a system, since $i$ and $\unaryminus i$ play exactly the same role in $\C$ as each other, yet are to be regarded as distinct complex numbers.
In fact, there is nothing special about the numbers $i$ and $\unaryminus i$ in this argument. For example, the numbers $\sqrt{2}$ and $\unaryminus\!\sqrt{2}$ also happen to play the same structural role in the complex field $\C$, because there is an automorphism of $\C$ that swaps them (although one uses the axiom of choice to prove this). Contrast this  with the real field $\newcommand\R{\mathbb{R}}\R$, where $\sqrt{2}$ and $\unaryminus\!\sqrt{2}$ are of course discernible, since one is positive and the other is negative, and the order is definable from the field operations in $\R$ via $x\leq y\iff\exists u\ x+u^2=y$. It follows that the real number field is not definable in the complex field by any assertion in the language of fields. In fact, there is an enormous diversity of automorphisms of the complex field; one may move $\sqrt[3]{2}$, for example, to one of the nonreal cube roots of $2$, such as $\sqrt[3]{2}(\sqrt{3}i-1)/2$. Therefore, the numbers $\sqrt[3]{2}$ and $\sqrt[3]{2}(\sqrt{3}i-1)/2$ are indiscernible in the complex field---there is no property expressible in the language of fields that will distinguish them. Indeed, except for the rational numbers, every single complex number is part of a nontrivial orbit of automorphic copies, from which it cannot be distinguished in the field structure. So the same issue as with $i$ and $\unaryminus i$ occurs with every irrational complex number. For this reason, it is problematic to try to identify complex numbers with the abstract positions or roles that the numbers play in the complex field.
Meanwhile, one may recovers the uniqueness of the structural roles simply by augmenting the complex numbers with additional natural structure. Specifically, once we augment the complex field $\C$ with the standard operators for the real and imaginary parts:
$$\text{Re}(a+bi)=a\qquad\qquad\text{Im}(a+bi)=b,$$
then the expanded structure $\langle\C,+,\cdot,\text{Re},\text{Im}\rangle$ becomes rigid, meaning that it has no nontrivial automorphisms. Thus, every complex number plays a unique structural role in this new structure, which is Leibnizian. This additional structure is implicit in the complex plane conception of the complex numbers, which is part of why the number $i$ appears fine as a singular term---it refers to the point $(0,1)$ in the complex plane---whereas $\unaryminus i$ refers to $(0,-1)$. The complex plane is not merely a field, for it carries along its coordinate information by means of the real-part and imaginary-part operators, making it rigid. In the complex plane, every complex number plays a different role.
This answer was copied from a related post at meta.mathoverflow.
Comment: I think this ought to be the accepted answer!
Answer: You asked for an elementary explanation of the difference between i and -i. Multiplying a complex number by i rotates it by 90 degrees anti-clockwise, multiplying by -i rotates it by 90 degrees clockwise. Sure if I repeat either one twice I have rotated by 180 degrees (or multiplied by -1) but I can still distinguish one from the other.
Comment: If you could only use words, and could not use physical expression, could you describe clockwise or counter-clockwise? right or left?
Comment: That is an interesting question - is there an algebraic definition of orientation in the (complex) plane. For the question that was asked for an elementary explanation of difference between i and -i and I think it is reasonable to use the complex plane and the natural notions of geometry that students usually already know. Here is my attempt at describing clockwise in words - if you multiply a complex number by another complex number of length 1 that is close to 1 then if the y coordinate increases it is an anti-clockwise rotation and if it decreases it is clockwise.
Comment: Of course, since we can arbitrarily define coordinates increasing, we're back where we started.
Comment: Yes there is an automorphism (a mirror reflection of the complex plane) that swaps i to -i and changes clockwise to anti-clockwise. I don't think that affects the above way to explain the difference between i and -i

How to tell $i$ from $-i$?


How to use email to message someone on Facebook

Question: I want to use my email (in apple mail app) to send a message to a friend on Facebook. Is there an email I can send it to from my mail app? Is this even possible?
Answer: No, as of now it's not possible. You cannot send message on Facebook via email. This feature is not available now.


How do I install Unity 3-D web player?

Question: I want to install the Unity 3-d web player on Ubuntu 11.04. I would like to use it on different sites such as http://firecraft.games2be.com/play. Is it possible?
Answer: Their website says the plugin is only available for Windows and MacOS X:

Unity Web Player
The Unity Web Player is not currently compatible with the operating
  system that you appear to be using.
Unity Web Player for Windows
  Internet Explorer, Firefox, Chrome, Safari, Opera
Requirements: Windows XP/Vista/7
Unity Web Player for Mac OS X
  Safari, Firefox, Chrome
Requirements: Mac OS X 10.5 or newer

Your best option would be to install Windows in a VirtualBox and use it to view those sites.
Answer: Unity 4 will introduce Linux support, according to their website. Unfortunately, it will be a few months before that is released.
You can check out their webpage here. You can use CTRL F to launch the find utility, then type in "linux" to scroll down to that section
Comment: It will probably be shown off at the Unite 2012 Developer Conference in August, and then will probably be released a few months later. Reports have said later 2012/early 2013
Comment: This still does not include Linux support for the Web Player - at this time anyway.
Comment: This is great info. Is the beta version out?
Comment: http://forum.unity3d.com/threads/unity3d-on-linux-with-wine-support-thread.211059/ provides updated instructions.  http://wiki.unity3d.com/index.php/Running_Unity_on_Linux_through_Wine and http://wiki.unity3d.com/index.php/Running_Unity_Web_Player_on_Linux_using_Pipelight are also helpful.
Answer: This is what I would do
Mind you, this MIGHT NOT work but it shouldn't break anything. This is my technique for getting weird crap to work in wine.

Install wine
Install winetricks
Match runtimes/applications required in winetricks (search net for exact requirements IE: needs Directx10.x or dotnet framework, fonts? etc...)

install direct3D, geko, etc...
Might wanna install Windows version Firefox or chrome under wine
Do a search for any other dependencies the program needs.

Attempt to install Unity 3D player in wine.
If failure, then: Review error for any "not found" or "error in/on _ _ _ _ _ and search the term for any "This happens when you dont have _ _ _ _ installed" or "needs _ _ _ libraries"
Repeat

Hope it helps.
Answer: The nearest result we had with unity web player is to install Firefox on Wine 1.4 and try to load Unity web player.
it will start loading the unity plugin with failed at updating it and then running it.
Sorry there is no solution with Wine currently (which is a shame)
I'm happy to see that they will support Linux in next version.
then the best way for you is to use XP in VirtualBox with 3D acceleration.
Answer: Pipelight is available to install Unity 3D web player and lots of other Windows plugins

Pipelight is a wrapper for using Windows plugins in Linux browsers and
  therefore giving you the possibility to access services which are
  otherwise not available for Linux users. Typical examples of such
  services are Netflix and Amazon Instant, which both use the
  proprietary browser plugin Silverlight. These services cannot normally
  be used on Linux since this plugin is only available for Windows, and
  the only open source alternative (Moonlight) is lacking support for
  DRM.
Pipelight helps you access these services by using the original
  Silverlight plugin directly in your browser, all while giving you a
  better hardware acceleration and performance than a virtual machine.
  Besides Silverlight, you can also use a variety of other plugins that
  are supported by Pipelight. Take a look at the installation page for a
  complete list.
Pipelight uses a patched wine version to provide a windows environment
  to the plugins, but you do not need to worry about this as Pipelight
  will take care of installing, configuring and updating all supported
  plugins. From the perspective of the browser these plugins will behave
  just like any other normal Linux plugin after you have enabled them.

Installation instructions are available here: http://pipelight.net/cms/install/installation-ubuntu.html
Additional steps are needed to enable to Unity 3D web player plugin in your browser, which are detailed here: http://pipelight.net/cms/plugin-unity-webplayer.html
Answer: The player you said doesn't seem to support Linux as of yet. It would be really hard to get this working and not worth your time.
Did you try using the Internet Explorer that ships with Wine? Try installing the latest version of Internet Explorer on Wine and see if that plugin installs in that browser. Download it first, put it in that virtual C drive and keep doing something until it works/ breaks.
If that doesn't seem to work, you may try VirtualBox like Sergey suggested, but i think it would be useless to play games in VirtualBox.
Something not related to question: If you want to watch some videos in 3D then try Bino player. It enables you to watch videos in 3D... So, if you wanted to watch a video in 3D, you can use it.
Or may be you can record your browser screen and later watch it in 3D, but that just sounds crazy. There are some players like this in software center, so check out if any of them helps you in watching your browser in 3D. May be you can try your luck with Firefox addons too.
Answer: They are about to launch the Unity4 preview which will provide a Linux client.
I think it will be available during the summer. The best thing to do is probably to pre-order the new version just here : http://unity3d.com/?unity4
Maybe you will have a beta access :)

How do I install Unity 3-D web player?


MPD ignoring music_directory specification in config

Question: I have been struggling with MPD for several hours now. I have referenced nearly every post that has been made on the issue of MPD failing to detect the music directory properly and have made no progress. In my configuration file, I have specified 'music_directory' as both /home/user/Music and as ~/Music several times in different methods, I have completely removed and purged mpd and reinstalled it twice, deleted all old configuration files, and remade these configurations. The only thing that has solved my problem is moving the music library to /var/lib/mpd/Music despite this not being the specified music directory. I don't want to have to resort to using this as a solution, as my I have /home on a separate partition and dont want to waste my limited space in the system partition
mpd config
db_file "/home/user/.mpd/db"
log_file "/var/log/mpd/mpd.log"

pid_file "/var/run/mpd/pid"
music_directory "~/Music"
auto_update "yes"
user "mpd"

Any help would be appreciated I'm at my wits end
Answer: The music_directory needs to point to an absolute path, for instance:
/home/thisuser/Music
Comment: I've tried using an absolute path for music directory, does not solve the issue


Should View Models always contain the inputs for forms in that view?

Question: This question is related to this one, but I think in my example I have detail which may alter answers.
Say I have a User action on a Controller that renders a View for displaying data about a particular User, it might have a UserViewModel like so:
public class UserViewModel {
    public string FirstName;
    public string LastName;
    etc...
}

However, in this View, as well as showing this user data, I want to have a search textbox for the user so they can look up another user on this page. This form would post into an action of FindUser, which accepts the following model:
public class FindUserInputViewModel {
   [Required]
   public string SearchQuery;
}

If this action finds the model to be invalid, it redirects back to the User action, maintaining the ModelState.
Now, currently to show the validation error, I cannot use a strongly-typed helper as that search query property isn't in UserViewModel, I'd have to do this:
@Html.TextBox("SearchQuery")
@Html.ValidationMessageFor("SearchQuery")

This works, and the error will be displayed, as well as the old value that was POSTed being shown (as it is persisted in the ModelState). However, I'd prefer to use a strongly-typed helper wherever possible.
From all the examples I have seen, the pattern here seems to be that the UserViewModel should contain the FindUserInputViewModel inside it, perhaps as an FindUserInput property. I could then do:
@Html.TextBoxFor(m => m.FindUserInput.SearchQuery)

This also works, as long as I make sure my FindUser action binds to the correct prefix, or I specify a name in the TextboxFor method call.
However, I don't really see why my UserViewModel should contain this other ViewModel simply for the case of binding the validation using this helper. Does it bring other benefits that I am not seeing? I understand the use of it if your View's model is needing to render out the same data you are posting, such as on a typical Edit action, but that isn't the case here.
It looks like to me that what would be handy here is a another generic helper that can reference a different type, something like this:
@Html.TextBoxForType<FindUserInput>(m => m.SearchQuery)

This doesn't exist, but I think I should be able to write that, and this is a good case for one. Does that sound like an appropriate solution, or am I missing something here?
Another option entirely is perhaps that the small-form for posting in that FindUserInputViewModel should have its own GET action as well as POST, and then the User View can just call into it using @Html.Action. It could then render a partial-view that is only strongly typed to FindUserInputViewModel.
Answer: Why not create a partial view for your search and simply pass this a new FindUserInputViewModel from your user view?
@Html.Partial("FindUser", new FindUserInputViewModel())

You can type your partial view to FindUserInputViewModel and use strongly-typed helpers in there. I'd say this is the simplest and neatest approach, unless there's something I'm missing?


Legal definitions in the United States

Question: When trying to learn about and understand law, one of the most important aspects of it is the legal definition of a word. Is there a source in which the courts refer to when looking to define a word? If there is, what is it?
Comment: I don't think terms necessarily have single 'official definitions', they have meanings in context, and might mean one thing in one context and something else in a different context.
Answer: Courts look to primary authority first, and then to secondary authority if ambiguity remains.
Primary Authority providing definition for the legal use of a word would be previous case opinions that give meaning to a word in a given context, how the word is actually defined in the statutes for the state, or, in the case of federal law, the federal statutes or Code of Federal Regulations. Within primary sources, you also consider whether a prior definition is binding on the court (i.e., the court has to follow it) or whether it is merely persuasive authority (that the court can choose to follow, but is not required to follow based on precedent – sometimes call Stare Decisis).  Primary authority is binding on a court if the definition comes from a higher court in the direct appellate chain of the deciding court, it is persuasive otherwise.
Secondary Authority is everything else. For example, Black's Law Dictionary, Whigmore on Evidence, or any other legal treatise would also be a secondary source. (All secondary authority is persuasive authority.)
Courts, in absence of either, will look to how a word is commonly used in the context in which it is applied. All seek to give the proper meaning to a word or phrase in light of how it is being used.
Answer: In my experience, I have seen such definitions in the preambles to legal agreements and contracts. For example, in a rental agreement, it defines words like dwelling, tenants, landlord, handyman, etc.  If the word was defined in the legal document you signed on, then it suppresses the dictionary definition. I highly doubt that dictionaries offer significantly different definitions of the same words. That is where you can find loopholes. If the word was not defined in the contract, and there is an established difference between the local lingo definition and the dictionary definition. So it is up to the lawyers to convince the court/judge/jury to take the "right" definition into account.
Wiki: "In the United States, the law is derived from five sources: constitutional law, statutory law, treaties, administrative regulations, and the common law (which includes case law)". Therefore, if you read those legal documents, you will notice at the start of each law a definition of each "legal word". For example, The Massachusetts General Law is divided into Parts, Titles, Chapters, and Sections. Once you start diving into each layer, you will notice that some of the Sections have a "Definitions" section for words and phrases.
UPDATE
As the Wiki entry says, the Black's Law Dictionary is only one of the so called secondary authorities. A Secondary Authority comes to "explain the meaning or applicability of the actual verbatim texts ofprimary authorities". A Primary Authority is usually in the form of a document that establishes the law, and if no document exists, is a legal opinion of a court.
From Wiki: The traditional law dictionary with definitions of legal terms serves to help users understand the legal texts they read (a communicative function) or to acquire knowledge about legal matters independent of any text (a cognitive function).
So, the legal definition of words and phrases should be defined as clear as possible in the law itself (e.g., the definition sections of the MGL noted above). If not defined, the Secondary Authority can be used to explain what they supposedly meant. But, I am sure that different resources can have different opinions on what is what. That's where the lawyers come in handy if they can convince the court to accept one meaning over another.
Comment: So what is the application of http://en.wikipedia.org/wiki/Black%27s_Law_Dictionary ? From my understanding, I thought this is where the courts look to the "official" definition of a term.
Comment: As the Wiki entry says, the Black's Law Dictionary is only one of the so called secondary authority. A Secondary Authority comes to "explain the meaning or applicability of the actual verbatim texts of [primary authorities][5]". A Primary Authority is usually in the form of a document that establishes the law, and if no document exists, is a legal opinion of a court. Now, lets say that you are a very well known lawyer, or a judge. Your legal opinion could potentially be considered as a Secondary Authority, and it can still be the opposite of what is written in those dictionaries.

Legal definitions in the United States


Neither ...or/and..., nor ...or/and...

Question: Can I say "It's neither humanitarian or environmental, nor political or ideological, nor economic or management crisis." Is it ok to use "neither ..or.., nor ..or.." or perhaps it's better to say "neither ...and..., nor...and..., nor...and..."?? I just dont want to write so many "nor"-s: "It's neither humanitarian, nor environmental, nor political, nor ideological, nor economic, nor management crisis."
Comment: "The crisis is neither humanitarian, nor environmental, nor political, nor ideological, nor economic, nor management." Is how I would structure it unless you want to completely reword it. [Try reading this](http://www.quickanddirtytips.com/education/grammar/when-use-nor)
Answer: Frankly I think it sounds best with the word nor throughout.
To use "nor ... or" is inconsistent, and to use "nor ... and" will turn the meaning of the sentence into something completely different than you intended.
If you don't want so many nors, use commas:

It is neither (sic) humanitarian, environmental, political, ideological, economic, nor management (sic) crisis.

There are still some questionable usages in the wording of this sentence that it inherited from the original, two of them indicated by sic.
First, you used neither when there are more than two alternatives. (I would note, however, that while some people might find this questionable, it is not definitely wrong.)
Second, the word management is a noun, while the other alternatives are adjectives. The phrase management crisis is a legitimate usage by itself,
but in this usage management binds to crisis much tighter than an adjective would: grammatically, you can have a political and ideological crisis but not a management and economic crisis.
So the sentence lacks parallelism.
Third, the sentence is missing an article: "It is a crisis" is grammatical,
but "It is crisis" is not.
One possible suggestion is,

It is neither a humanitarian, environmental, political, ideological, or economic crisis nor a management crisis.

I would not be satisfied with this in my own writing, but I think it's an improvement. In order to write this really well, I think you have to organize the ideas a little differently.
Some alternatives that may work better were suggested in a comment.
One is to use an adjective such as managerial rather than the noun management, preserving the parallelism of your sentence.
Another alternative is,

It is neither humanitarian, environmental, political, ideological, nor economical, nor is it a management crisis.

(This is a direct quote from the comment by Janus Bahs Jacquet; I cannot take credit for it.)
Which of these alternatives works best for you would depend on what you really meant by the original sentence. When you wrote environmental,
for example, did you mean to say that "this" is not any kind of environmental issue, or did you specifically mean to say it is not an environmental crisis?
Comment: Note that using _(n)either_ with more than two elements is [perfectly fine](http://english.stackexchange.com/q/103148) to most people, including some very fine authors. Also, your rephrasing is assuming that the parallel is meant to be on different types of crises. While that's definitely a possibility, it's not the only one. For yours, I'd suggest "It is neither a humanitarian, […] economic, nor managerial crisis"; but also possible is "It is neither humanitarian, environmental, political, ideological, nor economical, nor is it a management crisis".
Comment: @JanusBahsJacquet Thank you, those are very well-made points and I have modified the answer to try to take them into account.
Answer: You do not need to repeat "nor" for each item in the list.

This crisis is neither humanitarian, environmental, political, ideological, economic, nor related to management.

Edit:
Since comments sometimes disappear, and are not searchable, I will preserve the Janus version from the comment in this answer:

"It is neither a humanitarian, […] economic, nor managerial crisis."

I confess I had not noticed this comment when I wrote my answer.  And similar to OP, I like this version better than the sentence I proposed.  But it's the same basic idea -- use "nor" only once at the end.
Comment: Dear friends, thanks a lot for your answers, they were very helpful!! I think I'll go with the version @JanusBahsJacquet suggested, although the other comments  were also very useful for me. Huge thanks!
Comment: In a flat, technical sentence like the example, the list (with an Oxford comma and "nor" before the last word) is the best choice, but if you want to emphasize how _numerous_ the items are, repeating the "nor" is an excellent rhetorical device.  "I received food on neither Mondays nor Wednesdays nor Fridays!"
Comment: @Malvolio - What is an Oxford comma?
Comment: @aparente001 -- [Something I learned](http://mentalfloss.com/article/33637/best-shots-fired-oxford-comma-wars) from my parents, Ayn Rand and God.  Three things I hate are lists, Oxford commas, and irony.

Neither ...or/and..., nor ...or/and...


Is the process of design slow?

Question: I'm working on a project where a bunch of software (C++/OO) is being ported to a new hardware environment. A certain percentage of the software modules should be subjectively similar on the new hardware platform.
A code review for some of these modules has shown that the port done is been done with a minimal effort or insight - the developers doing the work are inexperienced, as often happens with porting. However it has also shown that the design of the software is lacking - either over-complicated, handles error conditions badly or just has a bunch of 'code smells'.
I have asked that instead of reviewing code after the port has been 'done', we review the design first. However, I am told that this might not be a good use of time, probably because the existing documented designs are not up to date.
Am I barking up the wrong tree? Is a design process inherently slow? Is there a way to avoid getting bogged down in the full design process. Or is hands on code always the best way to sort things out - even with inexperienced coders?
Update.
Thanks for the answers so far. Yes the s/w will be used in many (hopefully) future products/revisions. Also I didn't mention that the code is going to be multi-threaded too (previously a single threaded environment). This alone maybe good enough to indicate "review the design" I would like to proactively (yuck) see if a process of design review can be put into porting. I'm distrustful of just hoping to fix something up when it stops working - if something is found in testing to be fundamentally broken I'd rather not redesign come defect fixing time.
Answer: Get it ported, make sure test coverage is good, and consider refactoring/re-design once you have a fully working, well-tested app on the new platform.
Answer: I believe that if you're porting app A from hw X to hw Y, then port A from X to Y. Who will benefit from a re-design? I mean, if A does not change in functionality, then what will the business in question gain from your re-desing?
Comment: I agree but I don't have statistics. But an existing bad design can have a history of problems either in number of bugs that had to be fixed or have a high error injection ratio i.e. fixing it causes further bugs to in introduced.
Answer: There has to a business benefit to the redesign, and by business benefit I mean "this redesign will reduce our time to market significantly in future releases". Are you going to be porting this code elsewhere in the future? Will you be making future releases with significant new features? If so then it sounds like there's definitely a case to be made for at least investigating a redesign.
Or, is the project mostly in maintenance mode with no new development scheduled? In my experience, re-architecting/redesigning code in this state is usually just a developer exercise and provides no tangible business benefit to the organization.
Answer: Sounds like a redesign would be a good idea, if for nothing else than to separate the h/w dependent parts from the rest.  At least then your next port could focus on only those parts that really needed to change

Is the process of design slow?


How can I send multiple commands to Interactive telnet/ssh session from command line?

Question: I have a problem with one of the tasks I'm working on at the moment. I have to execute 2 commands in the interactive telnet/ssh session from the level of command line.
I have managed to login to the server using plink command line, but then the difficult part comes, I have no idea how to pass 2 commands to it and end the session.
Normally I do it in PuTTY by loading a session, then typing in:
53 Enter
GIVE 5 next 3 Enter
and here I close the PuTTY window.
I want to automate it, but I fail to pass the commands that should be executed into plink. Maybe I should have used other tool, but I'm running out of ideas on how to do it.
Answer: Try this:

Create a file input.txt with content:
53
GIVE 5 next 3

Run plink like this:
plink user@host < input.txt


Colored fringes in optics

Question: What optics principle is responsible for the colored fringes seen in the attached picture?strands of hair reflecting sunlight when held very close to the lens[]1]1
Answer: The colored fringes are probably due to a combination of diffraction and dispersive refraction, along the lines of how rainbows are formed by light scattering from water droplets in the air.
It's worthwhile to read the Wikipedia article on rainbows.  Note that "supernumerary rainbows" depend on interference.
The details of the color pattern you see in each "blob" in your photo are dependent on the orientation of the hairs, the position of the light source, the size and detailed shape of the hairs, and the distance of the hair from the lens.  If you really want to explore this effect, you could try setting up a spotlight for controlled illumination, put the hairs in a holder so they will stay still, and move the camera lens closer and farther away along a linear track so you can see how the lens-to-hair distance affects the pattern.  You might mount a hair vertically on a rotational mount and rotate it to see if and how the colors shift.  See if a very fine thread of glass, plastic, or sugar (cotton candy) does the same as a hair.  And so on.
Comment: Thanks. That gives me some insights.

Colored fringes in optics


Does Metal Bat need his bat for being more powerful?

Question: So Metal Bat is capable of doing a swing which destroys a building. For doing such a swing he would need an incredible strenght and for having that strenght he would need a very hard body (arms and fits included). What does the bat add here? Does Metal Bat need his bat for being more powerful? Has he ever been shown fighting without the bat and being very powerful too?
Answer: He indeed has an incredible amount of strength. From the One-Punch Man Encyclopedia,

When the intensity of Metal Bat's anger reaches its maximum, his power approaches infinity.

Aside from that, he also has extreme durability, enabling him to take many hits from higher-level monsters.
From one of the omake, it was said that he only acquired his unbreakable bat upon his promotion to S-rank. This means that he does not need the unbreakable bat that was made for him in order to defeat monsters, as any other bat would do, albeit it would break easily, as shown in the same omake.
Comment: Doesn't really answer the question of whether or not he *needs a bat* of some sort.  He's only ever depicted having used one.  Only answers that he didn't need an unbreakable one.
Comment: @zibadawatimmy Which was what the question is: 'Does Metal Bat need his bat for being more powerful?' I was assuming that 'his bat' is referring to his current bat, which is the unbreakable one. 'Doesn't really answer the question of whether or not he needs a bat of some sort. ' Yes, it does. It means he does not need a special bat in order to become a hero, 'any would do' albeit it would break easily, which was what I said. Can you clarify on what you mean by 'it does not answer the question'?
Comment: Yes: if he had *no bat at all*, what then?  As long as he's got *some* bat he's fine, but what about none at all?
Comment: @zibadawatimmy As I posted above 'When the intensity of Metal Bat's anger reaches its maximum, his power approaches infinity.' There was no special mention that he specifically needed his bat to be this powerful, only that his anger sort of 'activates' it. This is from the encyclopedia and I interpreted it as something that tells readers that yes, even without a bat, he still has nearly infinite power...
Comment: @zibadawatimmy My first statements in the answer were meant to show that even without a bat, Metal Bat still has nearly infinite power, among other things. I apologize if it is not clearly understood but that was my intention.
Answer: Um, he needs that bat. If he reaches infinite power.... Im pretty sure that a punch with that much force would shoot his arms of. Granted he hasn't trained like saitama has, hence the reason why saitama hasn't had his arms shoot of yet. If his power reached infinite, wouldn't he become as strong as saitama himself? If that's the case, then Metal bat's arms would shoot of if he punched with that much strength. So yes, he does need that bat.


Inductive kickback protection?

Question: Is there an integrated kickback protection in stepper motor drivers or should I make my own?
I am afraid the steppers might fry the driver or the arduino when i turn off the power for them.
I do that by turning off the power supply.
I haven't had an issue yet but it still bothers me.
Comment: What's this have to do with 3D printing?
Answer: Kinda, sort of, but not really. I'll look at the A4988 (datasheet).
The motor pins are connected by diodes to ground and Vbb (the motor suppply voltage). Essentially, they act as a bridge rectifier making any back EMF or inductive spikes appear (rectified) on Vbb. If you were to suddenly power down the driver this could cause a rather large spike on Vbb.
According to the datasheet, there is a 40 V Zener on Vbb which will clamp the voltage to that level. (Another popular stepper driver, the DRV8825, does not appear to have this Zener - always check your datasheet!)
So, yes, there is inductive kickback protection. However, it only clamps the voltage to 40 V. Depending on the rest of your circuit, this could be quite damaging.
The datasheet recommends that a 100 μF capacitor be placed on Vbb. If you are driving a typical stepper motor with 2 A and 4 mH coil inductance, the energy stored in the coil is 8 mJ. This energy is only enough to take the capacitor up from 12 V to ~17.5 V, so if you have a large enough capacitor on your stepper driver (as you should!) then you're protected against inductive kickback.
Note that if you move the motors by hand then you can still build up a higher voltage on Vbb. I've heard anecdotes of people who damaged their printers like that.
Answer: "Inductive kickback" from motor coils is caused by the inductance of the coils and the wiring.  It is not some strange effect.  Inductance is charged with current, just as capacitance is changed with voltage.  Most bipolar motor drivers use an H-bridge on the output.  By driving the H-bridge correctly, the driver can continue to provide a path for the motor current when it is no longer applying voltage, such as by connecting both wires of a motor to ground.
Although some may find it counter-intuitive, connecting the Vmot side of the motor to Gmot, while the other side remains at Gmot, keeps current flowing in the coil more smoothly and with lower losses.  The voltage across the motor coil is near zero, so there is little voltage trying to change the motor current.  If the coil is undriven and subject to the clamping diodes, the voltage across the motor will me much higher, and the current will stop faster.
The higher ripple current in the motor increases the coil heating, may increase audible noise, and decreases the efficiency of the drive.

Inductive kickback protection?


MySQL import and export data without update on insert

Question: I have a table that updates a timestamp column on every insert. This timestamp is indexed uniquely with a few other columns and I am unable to import this table. I guess the mysql dump/import inserts each row and some of the timestamps overlap because they are updated to the current timestamp. Is there a way to import and ignore the on update: current_timestamp() function that I have?
Answer: A unique timestamp is a mistake waiting to happen.
If there is also an AUTO_INCREMENT id, you can do this:
PRIMARY KEY(timestamp, id),
INDEX(id)

Then dups are not possible.
Comment: "A unique timestamp is a mistake waiting to happen." lulz.


What do I level a 2" slope in my concrete basement floor?

Question: I want to finish a 12'x36' part of my basement. The trouble I am having is that it is sloped to a floor drain. I was told that DRIcore and shims would work but the drain is a 2" slope down from the ends and that is way too much to shim. I do have a French drain system going around the exterior walls that drains to this drain so I need to find a way to bring up the floor and not affect the drain. The next trouble is that the floor is painted and I can't seem to remove the paint. Chemicals don't seem to work and a floor grinder didn't either.
Comment: For the second part of your question - is it surface painted, or does the colour go all the way through the concrete. If it is surface painted, a grinder or solvent will remove it.
Comment: why do you say shims will not work? are you planning to put down sleepers? (2x4 or such laying on floor to work like floor joists) and is ceiling low so you are trying to preserve headspace? Google "shim sleeper floor" and you should see some photos to explain best way to level floor. This will work for 2" slope and is commonly done, but you lose the 2" from the slope, and the height of the sleepers, and the thickness of the floor.
Comment: Do you want to use the drain (or is it building standard in your area to always have this drain working?) - I would answer just screte is with new concrete(but blocking the drain could have regional affects and my answer might be severely incorrect)
Comment: @RoryAlsop It could also be stained or acid tinted, in which case this color will likely never come out.
Comment: With the paint the surface is defiantly painted. I rented a concrete grinder and it did take off some of the paint but the finish has to much of a waive to it so it was only getting the top part and I burned up all of the disk that I had. It left it so you could see that it was just paint on top. I also tried a solvent but it just took off a slimy top layer. There was still some color on the cocrete.
Comment: With the drain a channel was cut in the concrete for the french drain to empty any water and a 3" PVC was put in and tied into the existing drain to the French drain. So the drain is all sealed now.
Comment: What material are you planning to finish the floor with?
Comment: I have not decided on that yet.
Comment: I'd leave the floor alone and build a second, floor over it which is level, and finish from that basis. of it, then finish from that basis.
Answer: I am currently finishing a basement and it almost seems like you are describing mine!  Slope, dimensions, and all.
If money is no object then have this section leveled.  Easy as that.  Will it drain properly.  No.
But if you are working on a budget and want it to look nice then you need to look at what options fit.  So ceramic flooring is out.  Hardwoods, even floating, is out.  So either carpet the floor or put down some rubber backed laminate (completely waterproof).  We are doing a combo of the waterproof laminate (they sell it in-stock at HD - Lowe's doesn't have it) and carpet in mine.  The waterproof laminate comes in like 30 different patterns, looks nice and costs about $3 a sq/f.  If your basement has potentially a lot of water issues I would go with the laminate.
Also a note on laminates... Water-resistant is not waterproof.  I let the HD stuff sit in a bucket of water and it didn't change for three days.  I also got some water-resistant samples (and even some cork-backed "water-proof") samples.  All of the others were mushy or expanded a lot after three days.  I have to think what would happen if I went on vacation and water got in.  Make sure the water-proof stuff is made out of pure "rubber".


Can we make use of coupling capacitors in a circuit with big voltage swings at its nodes?

Question: Can we make use of coupling capacitors in a circuit with big voltage swings at its nodes?
Do we need to utilize coupling capacitors in a power amplifier?  which we can do
away with a coupling capacitor in a power amplifier.
Comment: What do you mean by "make use of"? Coupling capacitors where? Across the supply rails? Between the output and loudspeaker? What problem are you trying to solve. Please [edit] to clarify.
Answer: The famous WIlliamson audio power amplifier, of vacuum tube fame, used 300 and 400 volt B+ rails.
There was ONE audio output transformer per amplifier.
Except for that last stage output, the other signal_path nodes were DC_blocked using capacitors.
With plate voltages along the load_line but up at 200 or 300 volts (thus about 100 volt drop across the plate load resistor, and grid voltages nominally at ZERO volts, the coupling capacitors had hundreds of volts across.


Which orbital class rocket has highest TWR at liftoff?

Question: Which orbital class rocket (active or retired) has the highest thrust to weight ratio at liftoff?
Comment: I thought this had been asked before, but if has, I could not find it.
Answer: I took the data from the JSR Launch Vehicle Database, available here. This includes take-off thrust and launch mass, so the Thrust-to-Weight Ratio was easily calculated. Unfortunately this list also includes many missiles and sounding rockets and I was too lazy too properly filter them with some other list of orbital class launch vehicles. However, eyeballing the list for orbital class launch vehicles with successful non-test missions, the Mu-3H seems to be the highest. It has a TWR of about 4.9, which certainly is quite high. Most of the Mu-family rockets have very high TWR.

After some further digging on the Mu-family I found a source in Japanese with sea-level thrusts and another (in English) with take-off mass for each configuration of the Mu-family rockets, which gives the following TWRs:

4.74 - M-3C
4.57 - M-3S/M-3H
4.52 - M-4S
Answer: Seems like JAXA's SS-520 with launch mass of 2,600 kg and 14,600 kgF average thrust would have TWR of about 5.6
data found here
Comment: Video of launch here - https://youtu.be/OeW-Qqu9-8U?t=28 6 G acceleration?
Comment: The only SS-520 that successfully completed an orbital mission was fitted with a 78kg third stage. Additionally, [the original paper](https://doi.org/10.1016/0094-5765(82)90107-2) reports a 14.2 ton average vacuum thrust, using some ideal rocket theory and the papers data the sea level thrust would be about 12.7 ton rounded up, i.e. 12.7/2.678 = 4.74 TWR  (admittedly the paper is from 1982 and the orbital flight using the SS-520 was in 2018, so not entirely unlikely they improved the thrust)
Comment: To be fair, I cannot find any specification for the Mu-3H thrust data so it might as well be vacuum thrust too. Consequently assuming a similar correction for the Mu-3H thrust, the SS-520 used for the TRICOM-1R launch would still have the highest TWR
Comment: Ah, this is one of the Japanese ones which does its gravity turn at T-∞ :-D
Comment: @JörgWMittag Not really -∞, just T-(couple hours) when the erector is angled to the launch angle ;)
Answer: Assuming that the question refers to thrust to "total vehicle" weight ratio, I would opine that the ratio is determined by the mission.  A heavy launch-to-orbit vehicle would be loaded to get the heaviest load to space and have a low thrust to weight ratio. An anti-missile missle would have a high thrust to weight ratio to accelerate rapidly and get to an approaching missile as far away from it's target as possible.  I don't see any value in this parameter as a figure of merit.
Comment: Using a high thrust to "total vehicle" weight ratio would result in a very rapid acceleration of the rocket and thus would require a stronger and heavier rocket structure. Also the payload structure should resist the rapid acceleration and would be heavier.
Comment: Somebody asks: "Which animal runs the fastest?" You telling them: "I don't see any value in speed as a parameter for classifying animals" is not a useful answer


Feature selection for 2D sample

Question: I have a dataset in which each sample has 2D matrix data, e.g., 50x1000 size matrix. Each of these 50 rows has different meanings. I convert this to 1*50,000 size data and use svm for classification. But now I want to find out the most significant rows for classification. I checked Sequential Feature Selection of matlab, but the problem is, it discards and takes some columns from row 1, some columns from row 2 etc. But I want to use each row as a group for feature selection so that either I take that whole row or not. Does anyone know any algorithms for this purpose?
Answer: Use PCA to collapse the 50 dimension down to e.g. 3 or 4 dimensions (or the number of PCs for which their eigenvalues > 1).   The information in the 50 will remain within the smaller dimension set, and in this fashion you also won't be using different features from the set of 50 for each sample.  PCA dimension reduction will employ a fair use of all the information form the original set.  Also, I would stack all the samples on top of one another (thousands of rows with 50 columns) and run PCA on the correlation matrix of the 50 columns.  Don't split the samples and run PCA on each (50x1000 array) sample separately.

Feature selection for 2D sample


How do I treat injuries in a caravan?

Question: One of my caravans was attacked by some manhunting Wargs and someone sustained some minor injuries. How do I treat this person while he is still in the caravan?
Comment: There is also a mod that allows caravans to set up camp. You basically load a small map (not the usual size) and can quickly set up a camp to do some basic stuff before packing up and leaving again.
Answer: You can make temporary beds and treat the wounds like you normally would if you were at the colony with a bed (aka having another person treat the wounds when they are in a medical bed).
(around 9:00 we can see this in the Alpha 16 preview)
Answer: Two very accessible, but not immediately obvious ways:

Under Architect > Furniture, place a Sleeping Spot
If you added Bedrolls to your caravan, grab one and place it on the ground

Since a bed is required in order to treat injuries, either option will allow another colonist to tend to injuries.

How do I treat injuries in a caravan?


How to install Adobe Flash and Java?

Question: New to Ubuntu. Need help on how to install Flash and Java.
Comment: See http://askubuntu.com/questions/366928/help-installing-some-java-and-flash
Comment: Welcome to AskUbuntu. Fortunately for you, it's a question that has been asked before and has several good answers . Don't forget you can search the site (see upper right corner).
Comment: First, open up a terminal and type uname -p. This. What does this mean? Have no idea
Answer: So here's my new and improved answer. Let me know if this is clear enough and helpful enough.
Rule of thumb, or how installing software works on Ubuntu
When it comes to software in Ubuntu, the Software Center program is you big and bubbly friend. There's , of-course other ways to install software, such as apt-get tool and dpkg tool. But for someone who's just starting with Ubuntu, Software Center should be simple enough solution.
First, Java
When you initially install Ubuntu and go to youtube, you realize that you need flash player, but once you go to install it , the adobe website will tell you that you need java. So the first thing you need is Java (obviously). There's two options here, Java that has been developed by Oracle, or free and open-source OpenJDK. The last one is simplest to install, and sufficient for most users' needs. Simply open Software Center, and type java. Select OpenJDK Java 7 Runtime and click install. Same thing with IcedTea Java Web Start.

Now, the small problem is that you need to enable Java in Firefox , if that's the browser you prefer. To do that, I use QuickJava add-on (because I'm lazy).  Simply type in firefox address bar about:addons, and it will open add-ons page. Search for QuickJava, install it, and once you got it, find it in the Extensions menu, click preferences, and check boxes bellow the things you want to be enabled in Firefox.

Moving on to flash
So now you are ready to install Adobe Flash player. This can be done in two ways: through their website:  http://get.adobe.com/flashplayer/  or through Software Center. Since this is a proprietary type of software, you probably might want to tell your Ubuntu to allow installing proprietary or copyrighted software. To do that go to System Settings -> Software & Updates ( under System ) , and check the boxes next to "Software restricted by copyright or legal issues(multiverse)"

Once you got that, like I said, you can download Flash through their website, or go to software center.

The small problem with flash player is that version 11.2 will be last one that Adobe developed for Linux, even though they will still provide support. There are alternatives to Adobe's flash player, such as Gnash and Lightspark. I've never tried them personally, but there's quite a few positive reviews of them. Again, they are in Software Center.

Chrome and Chromium
Now, installing flash player is a good idea, but if you want to avoid hustle, installing Google Chrome or Chromium is even better idea. They come pre-packaged with their own flavor of flash player. What's the difference between Chrome and Chromium ? Visually - there's no difference. Chromium is the open-source project from which Chrome and Chrome OS took jumpstart. As it is an open-source project, it is community maintained, while Chrome will have all the newest features, but it's controlled by Google.
As far as Chromium goes, it's simple - search Chromium in Software Center and install it.
Now, Google Chrome is a bit trickier. You have to go to the website: "https://www.google.com/chrome/browser/#eula" and download installer package.

Do you see where it says 32 bit .deb and 64 bit deb ? OK. Like  FuzzyToothpaste mentioned in his answer, 32 and 64 bit refer to which OS you have. Most likely you know that (after all, for installing Ubuntu you need to decide to install either 32 or 64 bit OS, based on your RAM memory ) , but if do not know that, open System Settings -> Details (same line as Software & Updates), and it should give you a summary for your system, and specifically you are interested in OS Type line.

Deb packages are sort of like zip for Windows. Once you are done downloading , drag and drop it into Software Center window, and it should open it. Alternatively, when your download starts, click "Open with " and it should have software center already selected.

What else to know
Ubuntu out of the box works perfectly fine, just needs  some small tuning. For instance, on 14.04 LTS version, it ships with muted audio. I've encountered this strange thing with some other members of askubuntu, as well as when I installed Ubuntu on Acer C720 chromebook, and upgrading from 13.10 on my Toshiba laptop. The solution is to open something called Terminal ( Ctrl + Alt +T ) or command line, and open alsamixer, which is like a sound manager. For more info you can refer to my answer here, on another askubuntu question.
Another thing: many codecs are proprietary, which means you have to install some ; so you'd need to get "Ubuntu Restricted Extras" in the . . .  .yes, Software Center. Did I say, it's your best friend when it comes to software?
Tweaking Ubuntu's look and feel can be done with one great app called Unity Tweak Tool. It gives you way to tweak theme, cursor, launcher and icon size, etc.
Another app that I really love, is Ubuntu Classic Menu. Basically , it's a drop down menu, similar to Windows XP's start menu, and it lists all software you installed by categories, so you don't need to search for stuff.
While Ubuntu is pretty fast, you might want to make it just a notch faster. Here is a great article that explains some of the methods to improve your boot speed and program start speed.
Linux has pretty much evolved over years, and now it's pretty user friendly. But since this is Linux/Unix type of system, I suggest you start getting acquainted with command line (aka Terminal). Many troubleshootings have to be done through command line, so at least have general idea. If you are a programmer/engineer who is starting to learn Linux - then you just must learn command line. Right now I'm reading Ubuntu Toolbox, which is really a good , general guide to starting out with Ubuntu, and command line over all. Don't be lazy , and invest into some reading, and that should get you started with Ubuntu in no time.
Good luck !
Comment: How to install chrome. Neither one of the options listed will work on Pogo. Says I need to update and have no idea how to update. TY
Comment: I'll edit my answer soon.  I'm just on phone right now.
Comment: What's pogo by the way?
Comment: Pogo is a game website. http://www.pogo.com
Answer: Well, I'm going to assume you want Google Chrome, which is the only way to get Adobe Flash 15 on Ubuntu. First, open up a terminal and type uname -p. That will tell you your processor architecture. If you already know it, skip this. If it says x86_64, you have a 64-bit processor (remember that for later). If you get iX86, where X can be 3, 4, 5, or 6, you have a 32-bit processor (remember that). If you get x86, that also means you have a 32-bit processor (it goes without saying, but remember that). Then use any old web browser like Mozilla Firefox or Midori to go to https://google.com/chrome and click the big blue "Download now" button. You'll see a box pop up asking you to choose from four different versions of Chrome. You want one of the top two (the .deb files) depending on if you're 32 or 64 bit. Click the appropriate radio button, scroll down, read the license agreement (like anybody ever does) and choose "Accept and Install". In some browsers, including Mozilla Firefox, you will be asked whether you would like to open or save the file. Choose "Save" or something similar depending on your browser. Let it download. Once it has completed downloading, open your file browser (Nautilus a.k.a. Files, Dolphin, Thunar, etc.) and go to your Downloads folder or where ever the file was downloaded to. Right-click on the file, move down in the menu to "Open With..." and choose "Ubuntu Software Center", "Muon", or "GDebi", whichever appears. Click "Install" and follow the instructions to install the file. Once it has been installed, you have successfully downloaded Google Chrome and Adobe Flash Player, but Adobe Flash Player will only work in Google Chrome. Now that's taken care of, let's move on to Java.
I'm assuming that by Java, you mean Java Runtime Environment. The only other option is the Java Development Kit and, unless you are a programmer that knows Java, you won't ever need. There are two kinds of Java Runtime Environments. Well, made by two different people. One is Oracle Java. It's hard to install and is proprietary, meaning it has a strict license agreement that restricts your use of it. The other is OpenJDK. It has less bugs, easier to install, and is free and open source software. OpenJDK is clearly the better choice, so I'll help you get set up with the OpenJDK Java Runtime Environment. Open up a terminal again and type in cat /etc/issue and press Enter. This will give you your Ubuntu version. If you get "Ubuntu Trusty Tahr", type the following command: sudo apt-get install openjdk-7-jre icedtea-plugin -y. If you get "Ubuntu Utopic Unicorn", type in sudo apt-get install openjdk-8-jre icedtea-plugin -y. If you get "Ubuntu Precise Pangolin" or something else, update your verison of Ubuntu. When you enter those commands, you will be asked for the super-use rpassword. This is not always your password. For information, contact your system administrator. One last note, the Java plugin you installed (runs Java applets in browser) works in every browser EXCEPT for Google Chrome. Don't worry about it. You probably won't need it.
Comment: This is the longest answer I have ever written on Ask Ubuntu.
Comment: P.S. If you're using Utopic Unicorn, installing icedtea-plugin will install OpenJDK 7 in addition to OpenJDK 8. After running the commands, type java -verison in a terminal to see if you're using 7 or 8. If it says 7, type this: sudo apt-get remove openjdk-7-jre -y && sudo apt-get autoremove -y

How to install Adobe Flash and Java?


How to Integrate Trac and WordPress (as done on the WP Development blog)?

Question: Back in May, I recall seeing a post on the WordPress Development blog by Alex M (Viper007bond.com) where he added functionality for Automatic Ticket/Revision/Diff Linking which allows for linking to Trac tickets, Trac revisions, and Trac diff comparisons.
I am wanting to do the same thing with an internal WordPress blog and Trac that I have for my business.  I haven't seen where this was released as a WordPress plugin so I was hoping that people could point me in the right direction on how to do this in how to do this integration between Trac and WordPress.  Thanks.
Answer: Here's the source of the functionality. It's just a content filter and some basic regex that one of my coworkers at Automattic wrote.
add_filter( 'the_content', 'markup_wporg_links' );
add_filter( 'comment_text', 'markup_wporg_links' );

function markup_wporg_links( $content ) {
    $find = array(
        '/(\ |^)#(\d{3,6})(\b|$)/i', // core trac ticket #1234-core in http://core.trac.wordpress.org/ticket/
        '/(\ |^)r(\d{3,6})(\b|$)/i', // core changeset r1234-core in http://core.trac.wordpress.org/changeset/1234
        '/(\ |^)diff:@(\d{3,6}):(\d{3,6})(\b|$)/i', // core diff diff-core:@20:30 https://core.trac.wordpress.org/changeset?new=30&old=20
    );

    $replace = array(
        '$0', // core trac ticket
        '$0', // core trac changeset
        '$0', // core diff
    );

    preg_match_all( '#[^>]+(?=<[^/]*[^a])|[^>]+$#', $content, $matches, PREG_SET_ORDER );

    foreach ( $matches as $val )
        $content = str_replace( $val[0], preg_replace( $find, $replace, $val[0] ), $content );

    return $content;
}

Modify it to suit your needs.
Comment: Thanks Alex, that is exactly what I was looking for.  I greatly appreciate your help and providing the code for this.
Answer: Also take a look at RTC (free for 10 users on jazz.net) it is the next big thing.
It automatically combines changing your stuff with the work items attached / diffs / with even your planning. It's the followup of Eclipse (which provided an open source framework).
IMHO the best thing out there currently


How to create nested folders in iCloud Documents?

Question: I can't create more than one level of folders in iCloud Documents from iWork. I really want to move my Documents folder (which is all iWork documents) to the cloud. It's neatly arranged in folders on my disk, but I can't just drag the folder to cloudify it. Is there any workaround to this problem?
Comment: how i wish that pages on ipad would allow to sync on dropbox or google drive.. have a hard time in arranging docs with no nested forlders
Answer: I'm afraid not. iCloud is designed for iOS devices without a user accessible file system. iCloud files are strictly associated with apps and only allow one level of folder nesting.
If you're not happy with this, you can send feedback to Apple about it here: http://www.apple.com/feedback/icloud.html
You could use Dropbox instead (https://www.dropbox.com/) which has more flexibility around file organisation. The downside is that you only get 2GB free but you can earn more free storage in various ways. Google Drive (https://drive.google.com/start#home) gives you 5GB free.
Comment: I am already using both of them. I have already given feedback about it. I was wondering if it was possible because on the Developer Builds, it gave you API to create folders.
Answer: You activate one of the iWorks applications, choose Open from the File menu, choose iCloud in the upper left of the dialog box. In here, you can drag and drop documents on each other just like you do on the iPhone/iPad/iPod Touch.
Comment: Welcome to AskDifferent and thanks for your input. Please reread the question again, the OP is asking for ways to put *folders* into iCloud, not documents.
Answer: I use a tag based filing system, so that I can group files from different applications into subjects.
The tags all have subject names and colours are only used to show them up.


What are the advantages and disadvantages of a token salary?

Question: I am writing an employment contract for a voluntary position at a charity and am wondering whether we should pay the individual £1 per year to demonstrate that they are a paid employee. What would be the advantages and disadvantages of this?
Comment: Are there minimum wage laws that apply to the position ?
Comment: Which is it? Volunteer or employee, as normally there is [no contract of employment as a volunteer](https://www.gov.uk/volunteering/volunteers-rights)
Comment: I edited out the word "peppercorn" because that is something different to a token (e.g. £1) amount. A peppercorn is literally [that](https://en.m.wikipedia.org/wiki/Black_pepper) and is often seen in older contracts (e.g. leases) *instead of* a token payment.
Comment: @JBentley: Note that in some places, a "peppercorn" is used as jargon/slang to mean a token payment, for the purposes of contract, e.g. https://en-academic.com/dic.nsf/enwiki/3412858 "one pound sterling as a peppercorn rent".
Comment: @sharur It's true that the terms are often used interchangeably. But technically, a peppercorn is an *example* of a token payment, just as £1 is another example of a token payment.
Answer: If you pay someone, they are an employe - not a volunteer
If they are an employee they have all the rights of an employee. This includes minimum wage laws so you can only pay them £1/year if they work less than 6 minutes 31 seconds per year.
Comment: -1 At least in the US, executive and profession\al  positions are exempt from minimum wage laws, and $1/year contracts are quite common, and are enforceable.
Comment: @DavidSiegel  the op is asking about England which, last I checked, is not in the USA
Answer: To be a valid contract, there needs to be a consideration on both sides.
A contract is not enforceable if it is void. A contract is void ab-initio if one side does not get any consideration at all. Some considerations violate public policy or are "Sittenwidrig" (~immoral) and thus are void. Also, contracts for something illegal are void.
Some examples:

A contract that promises Alice all of Bob's money but Bob gets nothing in return is not a contract that can be enforced as one. In the best case, it is a gift, promise of a gift, or trust, upon which relief can be granted.
A contract for sex (outside of prostitution!) is usually violating public policy and is "Sittenwidrig". As such, if Alice's contract with Bob reads, that Alice pays Bob but forces him to have intercourse with her, that contract is void: Consent to sexual actions can be withdrawn, and a contract that would overwrite that is null and void.
If Alice is an Assasin on Bob's payroll, the possible employment contract to go out and murder people for Bob is null and void: murder is a capital crime, so the contract is void.

To be an enforceable employment contract, it needs to fulfill labor laws.
Often labor laws stipulate a minimum consideration, which is the absolute minimum before a contract violates public policy. If the contract does not fulfill the stipulated minimum wages, the contract might not be totally void, but it most certainly isn't enforceable in the form written either.
A not enforceable contract might be cured in some way or another, for example by changing the payment value to the statutory amount, or by allowing the sides to cancel. In such a case, the law overwrites the contract.
However, other considerations also might be given as part of the pay and then their value is to be considered part of the wages. Such consideration might be very varied. Some of the more common ones are free access to facilities [but for work reasons] or goods in lieu of pay. Sometimes, these values are not easily quantifiable, but they are still considered part of the payment and have to be assigned some value. A few random examples:

My church's Janitor lives for free in a flat as part of his pay. The value of the flat is calculated by the price of a flat with a similar setup.
A trainee at a mechanics shop may use the machinery after hours for personal projects, provided they pay for the material. The value of such would be calculated by access fees to a similar fab-lab but is usually neglectable.
A personal trainer at a Gym is allowed to take up to a specified ammount worth of snacks from the snack bar without paying. The value of this could be the maximum amount of goods that can be claimed.
A farmer's farmhand takes a portion of the harvested goods as their payment. The value is obviously the fair price of these goods.
Comment: In most places, prostitution is legal, and therefore a contract between a prostitute and her client is not per se void. There has just recently been [a corresponding high curt decision](https://www.srf.ch/news/schweiz/strukturelle-diskriminierung-bundesgericht-lohn-fuer-sexarbeit-kann-eingefordert-werden).
Comment: @PMF the contract is void if it overwrites consent. THAT's different from prostitution being legal or not.
Comment: True, but that's the case for all contracts. If Bob suddenly asks twice as much as initially agreed on for his car, that's also against consent. IMHO, after the above verdict, it's hard to find examples for contracts that are by definition "sittenwidrig".
Comment: @PMF a contract is always Sittenwidrig if it demands a crime. If it misuses a bad situation of someone (e.g. excessive interest on a loan, which is anything above twice the normal rate). Likewise, agreeing to be mutilated (e.g. having your arm chopped off). What I mean with the contract can't overwrite consent to sexual things is, that you can't contract for example to be available for someone 24/7 or have a clause in a contract that demands such and such times intercourse as a part of being married. Such clauses are Sittenwidrig.
Comment: Yup, I agree to that now. I just wanted to point out that the example you gave above is (no longer) a good one. I don't know whether it would (still) be applicable for Germany, though.
Comment: @PMF Clauses for monthly sex in a marriage contract have been found to be void.
Comment: Note that the first section of this answer only applies to *simple contracts*. A contract can be executed as a deed in which case the issue of lack of consideration disappears.
Answer: You absolutely should not do this. A volunteer is, by definition, a person who chooses freely whether or not they work. They can turn up one day and work as you had hoped they would and the next day they can fail to show up even though they said they would, without any contractual repercussions.
An employee on the other hand is someone who has entered into a contract to work for their employer and has rights and obligations under that contract. An employee is not a volunteer because they cannot choose whether or not to work.
Therefore, the phrase "I am writing an employment contract for a voluntary position" is a contradiction in terms.
The biggest disadvantage you will face by using an employment contract (which you will impliedly do if the document grants a right to a £1 salary), as pointed out in other answers, is that the purported volunteer will acquire various statutory rights such as the right to statutory leave and the right to minimum wage. That is because, as soon as you enter into an employment contract with that person, they become a "worker" in law. See Section 54(3) of the National Minimum Wage Act 1998:

In this Act "worker" (except in the phrases "agency worker" and "home
worker") means an individual who has entered into or works under (or,
where the employment has ceased, worked under)—
(a) a contract of employment; [...]

Section 1(2) provides:

A person qualifies for the national minimum wage if he is an
individual who— (a) is a worker; (b) is working, or ordinarily works, in
the United Kingdom under his contract; and (c) has ceased to be of
compulsory school age.

There have been various cases in courts where purported volunteers have sued the employer, sometimes many years later, for very large sums in relation to back-pay and statutory leave, due to being deemed employees instead of volunteers. In the worst case scenario (e.g. the charity is structured as an unincorporated trust; quite common for smaller charities), the charity trustees can become personally liable for such claims to the extent that they exceed the charity's funds. Definitely not a situation you want to put the charity in.
The correct approach is to draft a volunteer agreement and to bear in mind the following important points:

Avoid the word "contract" or anything which implies that the document is legally binding on the parties. The word "agreement" is fine because contracts are a subset of agreements and an agreement doesn't become a contract unless there is consideration and intention to create legal relations.
Explicitly state that the agreement is not intended to be legally binding e.g.: "This agreement is binding in honour only, is not intended to be a legally binding contract between us, and may be cancelled at any time at the discretion of either party. Neither of us intends any employment relationship to be created either now or at any time in the future."
Avoid words such as "must", "shall", or anything which implies a right or an obligation on the parties. Instead use phrases such as "we hope that you will" or "it is preferred that".
For example, you might write a paragraph which states "Ideally, we would like you to volunteer for 4 hours every Tuesday and 4 hours every Wednesday if you are able and willing, but you are under no obligation to do so".
As Practical Law puts it (see links below), "volunteer agreements are generally short, informal in style, and phrased in terms of hopes and expectations rather than obligations".
Absolutely avoid any kind of binding commitment for the volunteer to work or any right to be paid a salary.
It is fine for the volunteer to be able to recover their reasonable expenses such as food and travel, but be careful to keep the scope narrow and to ensure that the volunteer can only recover their actual costs that they incur directly as a result of the volunteering. There has been case law to establish that something like an allowance of £25 per week for expenses can result in the purported volunteer becoming an employee because the £25 doesn't represent the actual cost of expenses and is therefore a salary (Migrant Advisory Service v Chaudri UKEAT/1400/97)
If you do pay expenses, make sure to keep receipts and documentation so that you can later prove that the payments were for actually incurred expenses.

This is the approach which is recommended by Practical Law and which I've adopted in my own charity legal work. If you have access to Practical Law then I recommend the following (paywalled):
Volunteering and internships: employment law issues
Standard document: volunteer agreement
If you don't have access, you may also want to take a look at the NCVO's guidance.


Extracting bibtex entries with regular expressions

Question: Is there a tool that allows me to extract bibtext entries matching a freely definable regular expression (e.g. all entries that do NOT contain the workd "example") without resorting to awk/grep etc.
Answer: After playing around with bibtool, I found out that it allows to "negate" filters:
bibtool '--select.non{key "example"}' literature.bib

Answer: biber has a new "tool" mode in the 1.5 dev version on SourceForge. With this, you can transform your .bib by using biber's reencoding and/or sourcemapping facilities as described in the manual. For example, to reencode your UTF-8 .bib and replace all UTF-8 with LaTeX macros:
biber --tool --output_encoding=ascii --output_safechars file.bib

To address the sorts of transformations you need, create a biber config file with a sourcemap section as per the manual. You can fairly arbitrarily transform the entries, including with regular expression search/replace, filter entries, drop/merge fields etc.
Bear in mind that biber 1.5 DEV requires biblatex 2.5 DEV from SourceForge for normal "non tool mode" use.


I have a problem making a anvil and i cant seem to find the cause

Question: im a beginner trying to get the hang of blender and while creating an anvil i found
this problem there seems to be my good mesh inside of this bad mesh i cant seem to find the answer anywhere. at the bottom you can see it the most but if i try to drag the model by any part the good model comes through whiste the blocky and bad looking one stays any ideas?
Comment: Why not just delete the mesh you want to get rid of?
Answer: I think that what you're calling "bad mesh" is the actual mesh without the influence of the subsurf modifier, while the "good mesh" is the result of the subsurf (and actually the result when rendered. When using the subsurf modifier, the vertices should be considered as "control points", which sometimes will not coincide with the rendered forms. To learn how to manage your control points and achieve the results you want, you should search for tutorials about "Hard surface modelling", in particular you'll have to get familiar with Edge control loops and edge crease. Lots of tutorials are available for free, like this: https://www.youtube.com/watch?v=nBkwodrQq_4.
Comment: yeah, this should be it!


How to undo a Bevel modification?

Question: Bevel in Blender is "simulated" by splitting edges into multiple faces. This results in a lot of crap which makes it harder to modify an edge afterwards. What is the best way to deal with it? I would like to be able to easily undo a bevel modification and reapply it after a line or vertex modification. I mean in a long term method, of course I can use the undo history for short but this is not usable after save and other modifications took place in between.
Please keep in mind that Bevel of different edges might have different parameters or diameters and so on.
I know you can store a Bevel modification per mesh but can this be done for parts of a mesh also?
If there is no easy way to manage a Bevel what might be the best procedure to disbevel an edge?
Comment: Modifications which were made by editing actual geometry (e.g. beveling in Edit mode) can't be "undone" as usual (unless `Ctrl`+`Z`). If it's important to undo some complex changes you can try to create simpler version of your mesh and add **Shrinkwrap** modifier on it, in order to wrap new mesh atop of beveled one. One of advantages of using modifiers is that they allow you to edit geometry without touching mesh itself.
Answer: I would use the bevel modifier, and not apply it, that way it remains editable, and suppressible.
Also You can Limit by Vertex Groups.
Everything you want all in one Modifier.
Answer: Also here's a tip that make your life a 100x easier. Hit Cmd+z to undo something you didn't want to do, like a mistake or so.

How to undo a Bevel modification?


Can you support a 20ft 2x6 only at the ends?

Question: Can you support a 20ft 2x6 only at the ends for a pergola?
Answer: 2x6 DF #2 Supported o the ends can handle about 11 lb. per Ln. Ft. total load.  This would include snow.  would recommend at least 2x8 if you are okay with sagging from wood creep after many years.  4x8, (2) 2x8, or 2x10 would be better.


Video Editor: Modify various strips of a subtitle text

Question: I try to modify various strips of a subtitle text in video editor but I don't find how to do it.
For exemple If I want to change the color of one line of text it is possible if I select one line and change in Strip/Style/Color. But if I select various lines and change the color in the color box it change only the color of the selected line with white selection.
Comment: That's something for scripting. There might be an add-on or special operator for it somewhere, but it can be scripted without too much trouble.
Answer: The white outline means that it is the active strip. The properties on the active strip is displayed in the sidebar.
The orange outline means selected strips.
If you want to copy the properties of the active strip to the selected strips, you'll need to press Alt while changing the values. Or right-click on the property and select Copy to Selected:

Unfortunately, this doesn't work for changing the font.
So, I added copying all visual properties of the active Text strip to the selected Text strips(including the font) to my Subtitle Import add-on.

Get it here: https://github.com/tin2tin/import_subtitles
Comment: I pasted your script in text editor and runned it. But the "copy properties to selected" option do not appear.
Comment: The "import subtitle" option well appear on the other hand. I use blender 2.93.8
Comment: Did you have both an active strip and selected strips selected(white+orange outlines)?
Comment: Yes and it is still the same. The button "copy property to selected" is not here
Comment: Since it is working fine here on 3.2, there is not much I can say other than try to update Blender.
Comment: I tried with blender 3.1.2 and it work. Thank you !


sql caching disadvantage?

Question: I have a web server with a lot of web sites with many database operations, and i am tryng sql caching as a way to improve the performance of my server.
In general, is there any disadvantage about sql caching in a common environment?
Thanks
Answer: Well, caching consumes RAM memory, so you'll need plenty of that.
I'm not sure about what caching mechanism SQL server employs, but it might be possible that your queries return stale data for some time.
Your best options of performance improvement is to load as much data into RAM as possible instead of caching.
Answer: The main problem with caching in a normal environment is cache expiration and stale data.
If you invalidate your cache every time data changes, you could end up rarely or never hitting the cache.
If you try to invalidate just the part of the cache that is changed, you have extra processing time to determine what to invalidate.
If you do not invalidate the cache or have cache timers, you may end up with stale data.
Depending on your environment and your requirements, you need to pick which solution best meets your needs.  Sometimes it is ok to have some stale data, and in other applications it is not.
Answer: All the above points are valid. Invalidation of stale cache entries would be a key concern as well as syncing local cache across multiple servers. You may want to look into a grid cache (e.g. Hazelcast, mem-cache) and Heimdall Data. Heimdall acts as a transparent cache and provides invalidation logic built in.
In summary, sql caching itself is a good thing to do. It increases performance and can buffer sql traffic away from the database allowing scaling benefits.

sql caching disadvantage?


Bridge pins that dont fit in

Question: I definitely do not want to break the bridge and even if the bridge pins are sticking out a few millimeters, that will make  palm muting irritating. Any suggestions?
Answer: Apparently slightly smaller (diameter) pins are available.
Use 100-120 grit sandpaper to rub the pins' diameter smaller.
Open up the bridge holes very slightly, using the next size drill bit, or preferrably a tapered reamer, checking very carefully and often.

Bridge pins that dont fit in


Improving readability by aligning elements in rows

Question: What's the best way to improve readability, when you have elements that change length like a name moving other elements, creating misalignment
Comment: By aligning the fields, you have just created columns.
Comment: If u r using tables to display, then fix rows with a percentage, so that they can have alignment according to data
Answer: Having the data arranged in columns (in a grid) makes it more readable.

The user can scan down the columns looking for the data they want without having to search for the information on each row.
If you use a grid control then you can introduce sorting and filtering of the data, allowing the user much more control over what information is displayed and how it's displayed - you might even be able to allow changing the column display order and visibility.

There is a limit to the amount of tabular data people can cope with, but you can get round this by allowing paging of your data so you only present 10, 25, 50 (or what ever) rows of data at a time.
Answer: There are pros and cons which can depend on the circumstances...

Aligning the data creates columns, columns can be given titles and have separators between them.

This enables fast visual scanning for a value of a certain column
You can enable users to hide columns, sort rows by column values and filter rows by column values
This is suitable when the max difference in data length in each column isn't very long, otherwise:

You will end up with a lot of white space and will need alternating row styles or horizontal dividers to make following a row from end to end easier
You may end up with an extremely wide table (due to added white space)
This can be addressed by creating mutli-line rows where the different columns are divided into lines (like Outlook's compact view)

Division to columns is suitable only if the types of values and their order are constant along the rows.