How mature is FreeBASIC?

Question: A friend of mine is considering using FreeBASIC in a critical production environment. They currently use GWBasic, and they want to make a soft transition towards more modern languages. I am just worried that there might be undetected bugs in the software. I see that their version number is 0.22.0, which indicates, that it is not quite mature yet. I also read this discussion, without being able to conclude. Also on their Sourceforge pages there is no indication of whether it is Alpha or Beta (which anyways is not a very good indicator). Does anyone have own experience about the maturity, ideas on how to judge the maturity, or know of companies using FreeBASIC in a critical production environment?
Comment: If they are using GWBasic anything is an improvement.
Comment: I suspect that transitioning from GWBasic to another BASIC dialect won't be as "soft" as you think. Hofstadter's law applies especially to rewrites.
Comment: @David Do they have a testing environment? It might be worth running one and hiring as a consultant one of the project developers, so he/she can fix bugs found in the testing run.
Comment: The FreeBASIC forums seem a better place to ask this question.
Comment: Version numbers are very project-specific things. Some projects reserve the major digit for something very special and just keep revving the minor and micro versions.
Comment: The current solution has been tested for 20 years, so they know all the bugs, but this has admittedly cost them quite a bit of money to find out.
Comment: @Matt Ellen, I am worried that they will be biased, as the people who have bad experience are less likely to be active on their forums.
Comment: @Rein Henrichs You might be right, but they have decided to go for this, so the only thing I can comment upon is the maturity of the compiler.
Comment: FreeBASIC might not even be that good of a replacement for GWBasic. [According to this](http://www.gw-basic.com/1/post/2011/2/gw-basic-to-freebasic.html) the two have enough differences as to make the task of converting from one to the other nontrivial.
Answer: PureBasic is probably your best bet instead of FreeBASIC but if i was you, i'd probably change to a more modern and robust language such as C# or Python.
Answer: I hope it's not too late to dig up an old thread.
I have used FreeBASIC in an industrial environment for 5+ years, and have found it to be rock solid. It actually worked very well back around 0.1, with growing QuickBASIC compatibility, and has slowly grown to exceed those roots and become more "serious" but can be told to work in a near 100% QB compatible mode. Fairly large releases only see the version number go up by 0.01.
I suggest your friend takes the GWBASIC to MS QuickBASIC, which should be quite easy (I've done it before, isn't it designed for 100% compatibility?). FreeBASIC then gives you a '21st century' option to run natively as a 32 bit app should anyone feel the need. Otherwise with Windows 7 etc, you're stuck using a VM running DOS or something.
Answer: Imho the best BASIC to use for upgrading from GWBASIC is PowerBasic (www.powerbasic.com). Many have done this before, so there's quite a lot of experience in Powerbasic's user community should you need assistance there.
Also Powerbasic is a high quality product with almost no problems/bugs and actively developed. It's not free ($199) but worth every penny.
FYI: I'm not affiliated with them and use VB.NET myself (for professional reasons; otherwise it would be Powerbasic ...).
Answer: Powerbasic is quite mature, and I would heartily recommend it, especially if dependability and great support are important to you. I personally don't use it anymore because it is not really designed for games programming - for which I use (and recommend) the cross-platform BlitzMax.
That being said, Freebasic should not be too much of a hurdle if you're coming from GWBasic, and seems to be reasonably stable as well. Documentation and forum support are better than average as well.
Still, if I were a company (as opposed to an individual) looking for a solution that will be there and supported for the foreseeable future, I would go with something like Powerbasic. here is a program that can convert QBasic to Powerbasic: http://www.powerbasic.com/support/downloads/files/QB2PBv2.zip
Hope this helps!
Russell
Answer: These are the following basic-dialects which are good both as compiler and embeddable script:
1) gambas
These are the following basic-dialects which are good only as compiler but can embed other scripts:
2) jabaco
3) objectivebasic
4) freebasic
5) chipmunkbasic
These are the following embeddable basic-dialects which are good, and can be embedded into other basic dialects depending on the frameworks:
6) scriptbasic
7) maven-sb4j
8) ajbasic
All these can also be used for making gui applications which differ with each other, database connecting tools, and in the area of embeddable applications (webserver pages), scriptbasic and gambas-gbs3 are already there, whereas if you can get fb-curl and fb-simplewebserver and integrate them into freebasic framework, then also freebasic-server-pages (if they are not there then you may have to download and copy-paste the library and header files under the lib and include directory of freebasic respectively). Even jabaco can embed maven-sb4j, or objectivebasic and chipmunkbasic can embed applescript and scriptbasic respectively. So these are likely to have have solution for most of the requirements.
If you are very particular with gwbasic compatibility then choose bwbasic (gwbasic enhanced for freebsd and linux), but I don't think there is much of any difference with some others.
However for graphics with bwbasic you have to contend with x11 based options or wait until it adds support for tk, fox, and other well known toolkits.
If you are willing to look for:
Robust vb-like development environment + basic server pages, then choose gambas or jabaco with maven-sb4j.
Robust interpreter supported with a thin but good ide: freebasic, and if you can get fb-curl and fb-simplewebserver and integrate them into freebasic framework, then also freebasic-server-pages.
Robust web-engine for basic server pages, then scriptbasic, and thinbasic.
So, these are all robust and may become usable at least after adding some few modules.
Borrowed some minor features from python/perl/ruby: scriptbasic (and also yabasic3)
Easy and very standard syntax: would be obasic (openbasic) in future, currently freebasic and scriptbasic are two varied flavors or traditional basic, whereas gambas and jabaco are a varied vb6 dialects.
Answer: What exactly is your use case? Or rather your friend's use case. I would be directing them toward Python (or any of the other widely used but also simple languages out there) but perhaps there is some specific reason why they need to be using a BASIC dialect.
I'm all for playing around with various languages in personal projects, but for critical production purposes I generally stick to languages that are widely known, widely supported, and very battle-tested.
Comment: I am not personally familiar with either FreeBASIC or GWBasic but I suspect it's not a small rewrite. Most BASIC dialects that I've encountered are actually quite different from each other. Pure Basic, Real Basic, Blitz Basic, GL Basic, etc. They are *conceptually* very similar (eg. not object-oriented) but the syntax is completely different.
Comment: This is not an answer, but more suited as a comment. The use case is that it is used for business critical calculation of material costs, labor costs, generation of 3D model etc. The current GWbasic program has around 30.000 lines of code (created by a single developer), which is the reason why a smaller rewriting is preferred compared to going to Python, which would require a complete rewrite.
Comment: Tempted to downvote anyone who favours "pretty" code over working code. It sounds like they have a large body of tried and tested GWBASIC, they are happy with its functionality, they would just like to move to a more modern language without having to re-write or re-design everything, which is perfectly sensible. Re-writing a large legacy system is one of the most arduous tasks you can ever embark on!
Comment: Moving to a more modern language without rewriting everything is a sensible first instinct, but not really practical in this situation. If the only reason to rewrite everything is to get "pretty" code then yeah that's a huge waste of time, but that's a reason not to switch languages. If however you have a real need to switch languages (this is an old thread so I don't recall if he did) then switching languages pretty much forces you to rewrite everything.
Answer: Then there is java-api support or japi for scriptbasic, yabasic2 and jabaco, which is cross-platform.
But of course now a days many basic-dialects have other cross platform toolkits too, which can soon pave way for quality applications in the future.

How mature is FreeBASIC?


Dual Boot and encrypting Linux?

Question: I have Windows and want to install encrypted Ubuntu (Home + Swap + System) - it giving me that option during installation when I'm choosing partitions so my question is will I be able to boot both Windows and Ubuntu when I encrypt Ubuntu  or will it break Dual Boot ?
Answer: If you encrypt your Linux partitions, this has no impact on Windows. You'll need a small boot partition for the bootloader anyway, regardless of whether you run only Linux or Linux plus Windows. Select manual partitioning during the Ubuntu installation, create an encrypted container, and make three logical volumes (/, /home and swap) on it. Make a small /boot partition (80MB minimum, 200MB recommended) outside the encrypted container. Make sure to shrink, not delete, the Windows partition. The installer will automatically pick up your Windows installation and offer dual boot.

Dual Boot and encrypting Linux?


Bluemix / Watson Natural Language Processing invalid API Key

Question: Have searched, but can't find similar issues in the past year. I'm trying to follow this tutorial, but things seem to have changed since it was published in April. I've got the PubNub Modules built and have registered a Bluemix Watson account and set up a Natural Language Understanding Service.
It when I try to run the test package in PubNub, I receive the error:
23:24:12  js:

[" TypeError: Cannot read property 'type' of undefined  at
  Sentiment/IBM Watson.js:46:43   at process._tickCallback
  (internal/process/next_tick.js:109:7)"] Error   at Sentiment/IBM
  Watson.js:76:21   at process._tickCallback
  (internal/process/next_tick.js:109:7)

23:24:13 js:
{ "body": "{ \"status\": \"ERROR\", \"statusInfo\": \"invalid-api-key\", \"usage\": \"By accessing AlchemyAPI or using information generated by AlchemyAPI, you are agreeing to be bound by the AlchemyAPI Terms of Use: http://www.alchemyapi.com/company/terms.html\", \"totalTransactions\": \"1\", \"language\": \"unknown\" }

The tutorial code for the api is this:
export default (request) => {
    // url for sentiment analysis api
    const apiUrl = 'https://gateway-a.watsonplatform.net/calls/text/TextGetTextSentiment';

    // api key
const apiKey = 'Your_API_Key';

but it seems as the the API format for Bluemix has changed since the tutorial was written. The Bluemix credentials are now in the format:
{
  "url": "https://gateway.watsonplatform.net/natural-language-understanding/api",
  "username": "x",
  "password": "y"
}

As someone who comes from using R as a statistical calculator and just programmed his first (primitive) battleship game in Python last week, any help much appreciated!
Answer: As you can see:

IBM Bluemix just announced the retirement of the AlchemyAPI service.
  They say to use instead the Natural Language Understanding service,
  also under Watson.

Natural language understanding doesn't use API KEY like AlchemyAPI. When you create your service inside IBM Bluemix, you can saw in the Service Credentials your username and password:

So, for use Natural Language Understading with Javascript, you need to follow the API Reference:
var NaturalLanguageUnderstandingV1 = require('watson-developer-cloud/natural-language-understanding/v1.js');
var natural_language_understanding = new NaturalLanguageUnderstandingV1({
  'username': '{username}', //Service Credentials
  'password': '{password}', //Service Credentials
  'version_date': '2017-02-27'
});

var parameters = {
  'text': 'IBM is an American multinational technology company headquartered in Armonk, New York, United States, with operations in over 170 countries.',
  'features': {
    'entities': {
      'emotion': true,
      'sentiment': true,
      'limit': 2
    },
    'keywords': {
      'emotion': true,
      'sentiment': true,
      'limit': 2
    }
  }
}

natural_language_understanding.analyze(parameters, function(err, response) {
  if (err)
    console.log('error:', err);
  else
    console.log(JSON.stringify(response, null, 2));
});

See the Official API Reference using Node.js
Demo to you saw how NLU API works.
Migrating from AlchemyAPI.


Strong markov property vs usual markov property.

Question: I was trying to understand the difference between strong Markov property and the usual Markov property for a discrete number of states. I think I understand why the strong Markov property implies the usual one : We have to consider a deterministic stopping time $T(\omega)=t_0$, right?
But what would be a simple example (like coin toss, dice toss,...) where we have the Markov property but not the strong Markov property?
Answer: Any discrete time Markov chain has the strong Markov property; the same holds for a continuous time chain with a stopping time that only takes a countable set of values. This is actually not too bad to prove, just conditioning on the particular realisation of the stopping time. You can read about the strong Markov property in James Norris' book, in particular Section 1.4 -- this is for discrete time.
As you point out, strong Markov implies Markov by just taking the stopping time deterministic. So you can't come up with a chain that has one but not the other :)
For continuous time, it is more subtle. These lecture notes give a counterexample -- Example 167. (The full lecture notes can be found here.)
Comment: @paperskilltrees I haven't thought a great deal about it, but I think that one reason is because of the need to have lack of invertibility at precisely one point, which has 'mass' 0. This rules out a discrete-space counter-example. Of course, one can have discete-time + continuous-space. I expect that this will have the issue that hitting particular locations will have probability 0. I'm not sure beyond this, though. Continuous-space stuff is not my area of expertise! You could ask a new question, though. If you do, please link here!
Comment: Could you clarify why the counterexample (Example 167) cannot be converted to the discrete-time setting? I can't quite put my finger on it.


History of the probe request?

Question: I'm interested in the individual history of the probe request specifically - when and where the agreements were made for the protocol to function as it does today.  Anyone have any good history lessons to share?
Answer: One idea would be to look at the minutes and reports from the IEEE 802.11 working group sessions at the IEEE website. I think they also keep the detailed proposals for all features online, you should be able to find even more details if required.

History of the probe request?


How can I look up exactly how delayed my UK train was?

Question: Earlier today, my UK train trip was delayed by signalling problems. When we set off, the guard announced about these, and said we'd probably be about 25 minutes late to our destination. (On this particular train company, 30 minutes is the magic number for delay compensation)
As we got to the area around the signalling problems, we seemed to get even later, and the guard announced we'd probably be 28 minutes late. When we arrived, I had to make a mad dash for an onward connection, so didn't have time to check the boards to see what they said.
I've tried looking on the National Rail Enquiries journey planner for the delay, but that won't let me search in the past. The National Rail Enquiries live departures and arrivals pages don't show things into the past either.
Is there any way to lookup the actual arrival time, for a UK train, for some point in the last day or two? (So I can check if the train hit the magic 30 minutes or not, before bothering to fill out the forms to try to claim)
Comment: I think all UK train companies are obliged to pay compensation for 30+-minute delays, so 30's magic for all of them. Also, note that the delay is to your journey, not to a specific train. So, for example, if one train is 15 minutes late and that causes you to miss your connection to a half-hourly train, the operator is still liable, because you arrive at your destination 30+minutes late.
Comment: This works both ways of course - if your mad dash to meet your connection (assuming that your connection was another train rather than, say, a non-rail-related bus) meant you didn't actually arrive at your destination half an hour late, then you shouldn't be claiming compensation.
Comment: @DavidRicherby Not all - some companies are still on schemes that pre-date Delay Repay. Some others, generally newer franchises, even offer compensation for shorter delays!
Answer: It is possible to look this up, just not on the main National Rail Enquiries sites!
You need to use one of the new third party sites which have got access to the underlying Network Rail real-time data feeds. (Details for the geeks on what's available described here). The sites which pull in that data includes OpenTrainTimes and RealTimeTrains
If you use one of those sites, you can then search for trains from the last few weeks. You'll see something a bit like this:

Which shows a 33 minute delay, enough for a compensation claim!
Comment: @DavidRicherby It does matter if the train company incorrectly rejects your claim, and you need to appeal it...
Comment: You need to claim compensation within 28 days of travelling so, as long as you can see at least four weeks, being restricted to "the last few weeks" isn't a problem for compensation claims.
Comment: @Tim Depends on the company. Worst Great Western I'd say it's about 1 time in 4, Thameslink seem to "accidentally" loose a lot of complaints and you have to shout at them again later...
Comment: There is also https://www.recenttraintimes.co.uk/ where it's easier to check for regular commutes.
Comment: Bear in mind that Open Train Times shows the real-time data from the official feeds, which is likely what the train operator will have available to them. Realtime Trains in many cases "knows better" and makes more accurate predictions based on different data; but while likely to be more accurate these are probably not the figures the people processing your delay will be looking at! In most cases there will only be a minute or two in it, if that, but a minute can make all the difference here.
Comment: @Gagravarr does that often happen?


Newly planted Hydrangeas do not look good

Question: My newly planted hydrangeas went from looking beautiful to dried up after yellowing. I tried to upload a picture but it's not working. They are watered every other day in the early morning and get sun mid morning to mid afternoon.
Comment: What are your temperatures like where you are - has the weather been  hot, dry and sunny? Are the hydrangeas planted in pots or in the ground? When you water, how much water does each one get, or, how are you watering them (hand held hose, sprinkler, can, irrigation...)?
Comment: It's been warm in the 80's. They are in the ground and are watered by a sprinkler system every other day for 20 minutes.
Answer: It sounds like insufficient water. Whilst 20 minutes via your sprinkler system every other day might be fine for lawns or plants which have been present in the ground for a couple of years, it's not enough for newly planted shrubs, especially given your daytime temperatures currently. Hydrangea particularly does not like dry soil, so if you want to save them, they need to be given probably a full watering can (or a gallon or two) of water each every day, poured at the base of the plants on the soil so it has some chance of reaching the bottom of their rootballs as well as the upper parts of  the roots. If they are in a really bad way, this should be done twice a day while the weather is hot and dry, or for a couple of weeks, then once a day for the rest of the summer.
If you dug those plants up now, you'd likely find their roots are still pot-shaped and bone dry; when your sprinkler is running for that short period of time, it will not be distributing enough water on the soil to soak those pot shaped root balls, which are probably 6-8 inches deep from top to bottom. 20 minutes with a sprinkler system will only wet the soil for the top inch or so, and the roots of any new plant take some weeks to 'break' out of the pot shape and venture out into the surrounding soil to gather their own water. Until they do that, they're dependent on you watering them deeply and sufficiently to keep them alive and healthy.


holomorphic vector field on Fano Kähler-Einstein manifold

Question: Let M be a compact Fano Kähler-Einstein manifold, V is a holomorphic (1,0) vector field. Fano conditions tells that $V=\nabla^{1,0} f$ for some smooth complex valued function.By Matsushima theorem, Kähler-Einstein condition implies that $div V=\Delta f$ is an eigenfunction of complex laplacian $\Delta$. My question is would it be possible to take the potential fucntion $f$ to be a real valued function?
Comment: If you just figured out a solution, please take a moment to stick it into an answer to your own question (that's allowed!) That's preferable to letting this sit around with no solutions. Thanks!
Comment: Hi Vicky: if at any time you think the physics forum might stand a better chance of answering this, let us know and we can try to migrate it.
Comment: yes, please. If there is some idea from physics, that would be great.
Comment: i add the argument to the answer part
Answer: Actually, I just figured out an argument. Take any holomorphic $(1,0)$ vector field, say $X$, then Fano implies $X=\nabla^{1,0}f$, with complex valued $f$. And $\operatorname{div} X=\Delta f$. Now let $f=u+iv$, then since $\operatorname{div} X$ is a $1$-eigenfunction of the complex Laplacian, so are $\Delta u$ and $\Delta v$, then by Matsushima theorem, one knows that $\nabla^{1,0}(\Delta u)$ is also a holomorphic vector field Which has real potential $\delta u$. Since the Laplacian is an real operator in the Kähler case.


What is the official name for a credit card's 3 digit code?

Question: I am working on a payment form.  What is that 3-digit code on the back of the card called?  I can't find a consistent reference as to what to call it.
Comment: I think we're slowly moving all of wikipedia's content to SO...
Comment: wikipediaoverflow!
Answer: It is called the Card Security Code (CSC) according to Wikipedia, but has also been known as other things, such as the Card Verification Value (CVV) or Card Verfication Code (CVC).

The second code, and the most cited, is CVV2 or CVC2. This CSC (also known as a CCID or Credit Card ID) is often asked for by merchants for them to secure "card not present" transactions occurring over the Internet, by mail, fax or over the phone. In many countries in Western Europe, due to increased attempts at card fraud, it is now mandatory to provide this code when the cardholder is not present in person.

Because this seems to be known by multiple names, and its name doesn't seem to be printed on the card itself, you'll probably (unfortunately) still need to tell your users how to find the code - ie by describing it as the "3 digit code on back of card".

2018 update
The situation has not improved, and is now worse - there are even more different names now.  However, you can if you like use different terms depending on the card type:

"CVC2" or "Card Validation Code" – MasterCard
"CVV2" or "Card Verification Value 2" – Visa
"CSC" or "Card Security Code" – American Express

Note that some American Express and Discover cards use a 4-digit code on the front of the card. See the above linked Wikipedia article for more.
Comment: FYI, not all cards written the code in the back side. AMEX cvv code is in the front and 4 digits.
Answer: You can't find a consistent reference because it seems to go by at least six different names!

Card Security Code
Card Verification Value (CVV or CV2)
Card Verification Value Code (CVVC)
Card Verification Code (CVC)
Verification Code (V-Code or V Code)
Card Code Verification (CCV)
Answer: It's got a number of names.  Most likely you've heard it as either Card Security Code (CSC) or Card Verification Value (CVV).
Card Security Code
Answer: From Wikipedia,
The Card Security Code is located on the back of MasterCard, Visa and Discover credit or debit cards and is typically a separate group of 3 digits to the right of the signature strip.
On American Express cards, the Card Security Code is a printed (NOT embossed) group of four digits on the front towards the right.
The Card Security Code (CSC), sometimes called Card Verification Value (CVV or CV2), Card Verification Value Code (CVVC), Card Verification Code (CVC), Verification Code (V-Code or V Code), or Card Code Verification (CCV)[1] is a security feature for credit or debit card transactions, giving increased protection against credit card fraud.
There are actually several types of security codes:
<code>* The first code, called CVC1 or CVV1, is encoded on the magnetic stripe of the card and used for transactions in person.
* The second code, and the most cited, is CVV2 or CVC2. This CSC (also known as a CCID or Credit Card ID) is often asked for by merchants for them to secure "card not present" transactions occurring over the Internet, by mail, fax or over the phone. In many countries in Western Europe, due to increased attempts at card fraud, it is now mandatory to provide this code when the cardholder is not present in person.
* Contactless Card and Chip cards may supply their own codes generated electronically, such as iCVV or Dynamic CVV.
</code>
The CVC should not be confused with the standard card account number appearing in embossed or printed digits. (The standard card number undergoes a separate validation algorithm called the Luhn algorithm which serves to determine whether a given card's number is appropriate.)
The CVC should not be confused with PIN codes such as MasterCard SecureCode or Visa Verified by Visa. These codes are not printed or embedded in the card but are entered at the time of transaction using a keypad.


Can elementary particles quantum entangle?

Question: I just want to know if elementary particles, such as a quark, can entangle with another elementary particle of the same kind. If so, does entanglement for elementary particles follow the same guidelines that entanglement between two normal particles (such as an electron)? In other words, is elementary entanglement different from normal particle entanglement?
Comment: Electrons and quarks are both elementary particles.
Comment: "Entanglement" is a short hand word  for "these particles are described with one wavefunction"
Answer: Both quarks and electrons are part of the Standard Model, our currently accepted theory, and both of these are elementary particles.
Entanglement (QM) is a physical phenomenon, that occurs when pairs or groups of particles are generated, interact or share spatial proximity in a way that the quantum state of each particle cannot be described independently from the state of the others.
https://en.wikipedia.org/wiki/Quantum_entanglement
Entanglement has been experimentally proven between:

elementary particles like photons, neutrinos, electrons
molecules
even small diamonds

The answer to your question, yes it is possible to entangle two different types of particles, and entanglement between elementary particles is the same quantum entanglement that you see between non-elementary particles.
entanglement of different types of particles possible?
Comment: Much appreciated.
Answer: Quantum mechanics is a particle theory, in which objects are described as "particles" instead of "fields" as in QFT. The objects studied could be molecules or atoms, even subatomic particles, depending on the scale you choose. This is same as describing the earth as a point of mass when studying Kepler motions. Here's a link about describing quarks in QM https://public.lanl.gov/mparis/qmp.pdf
Comment: please note that QFT is by definition based on quantum mechanics, postulates principles and laws included. It is just more sophisticated mathematically.
Comment: I don't think this really answers the question. Yes quarks is modelled as a field excitations rather than an individual point particles. How does that relate to whether they can be entangled?


I dug a pit to drain my sinks, bathtubs and washing machine water into, the water from the washing machine comes above ground. What have I done wrong?

Question: I dug a 8ft X 6ft pit to drain my sinks, bathtubs and washing machine water into. The ground had right much clay but was able to get past that and into sand. I put 4 ft of rock in the pit, ran a 4" pipe from the house to the pit resting in the rock in the pit. I don't have a problem with the bath or sink water, but the washing machine water comes back above the surface of the ground. I did not put any kind of barrel in the pit. Can anyone help me with this and tell me what I have done wrong? Thanks in advance on any suggestions to get this right
Comment: "*What is an illicit discharge?* The United States Environmental Protection Agency defines an illicit discharge as, "any discharge into a storm drain system that is not composed entirely of stormwater." This means that anything other than simply the water that falls from the sky is an illicit discharge. There are many hazardous household products, yardcare products, fertilizers, dog waste, car **soaps and automotive fluids that turn what should only be stormwater into an illicit discharge that pollutes and degrades local water quality**." https://cwsec-sc.org/what-is-an-illicit-discharge/
Comment: Presumably *what you did wrong* was fail to meet code for either of those types of systems (not that I know what that is, I'm municipal). And if you *did* met your code, you did the absolute minimum and should follow some code written in a country that has an EPA.
Comment: you still need soap filter, otherwise it will clog your drain.
Comment: "8ft X 6ft pit" - "4 ft of rock in the pit" - 8' long, 6' wide, and 4' deep, all filled with stone? So it's a french drain (filled with rocks covered with dirt? And you're discharging soap into it....) and you expect it to act like a septic tank (with actual capacity - opposed to a storm drain which is *'w/e'* if it comes to the surface, as long as it isn't next to the house, seeping in, and all grade pitches away). *How to build a septic tank?*
Comment: https://en.wikipedia.org/wiki/Dry_well
Answer: Washing machine puts out water faster?
I take

but the washing machine water comes back above the surface of the
ground

to mean you see water atop your pit.  If all three wastewater sources (sink, shower, washing machine) share the same drain line maybe it is because the washing machine drains a lot of water fast?  Or perhaps the sink and shower drain pipe systems are larger before they enter the common pipe and so act as a reservoir to limit the rate at which these wastewater sources enter the common drain.  The washing machine just goes right to the common pipe.
Your barrel idea is a good one.  Have a barrel in the pit with an opening in the bottom to allow it to drain into the sand.  Have the common wastewater pipe enter the barrel.  The barrel can hold a lot of water and then allow it to drain in an orderly manner.  Also if you put a screen or even a rag in the drain at the bottom of the barrel it will give you easy access and let you clean out scum, particulates and hair that will eventually clog up your sand and make your pit useless.
Last and an idea that I keep having - block the barrel drain and then use the graywater to irrigate thirsty trees in the summer!
You should put a cover over your barrel or animals might fall in at night.
Answer: Soap, Soap, Soap
Will clog your drain in no time.
You have the right size pit, of 225 cubic feet = 1,500 Gallons.
The washing machine outputs up to 40 Gallons.
So why is your pit not draining?
Look at he bottom and find out there is a soap layer covering the bottom. Over time it will simply fill up and spill over.
Since you are using slow drain in you pit, the soap will settle down and block it.
You need a soap filter before the pit.
You can buy one or build it your self.
There are many DIY soap filter, where using mosquito net is simplest.


Double Slit Interference pattern - horizontal or vertical?

Question: What determines whether in a double slit experiment the interference pattern will be horizontal or vertical for example? Is it mostly seen horizontal because the slits are small enough horizontally for interference pattern to be seen? Also, I sometimes see a "rectangular" interference pattern when using a lens to focus the light. How does that happen? Shouldn't we expect a circular pattern?
Answer: TL;DR

If the slits are sufficiently long the diffraction pattern will be spaced in the same direction as the slits.
If the length of the slits is of the order of the wavelength then the diffraction pattern will appear "rectangular".
One should only expect a circular interference pattern if the aperture has a circular symmetry for example a circular hole.

Explanation
The interference pattern observed from the double-slit experiment produced by particles is the same as that produced by light due to wave-particle duality. However, the scales of the interference patterns will differ as the scale depends on the wavelength.
The interference pattern can be calculated using the Fresnel-Kirchhoff diffraction integral. There are two commonly used limits of this integral, the Fresnel limit (screen or point source close to aperture) and the Fraunhofer limit (screen and source far from aperture).
For this question, we will consider the Fraunhofer limit as the results are easier to understand intuitively and also easier to calculate as in the Fraunhofer limit the amplitude of the interference pattern on a parallel screen is proportional to the Fourier transform of the aperture function (a function that is $1$ where light (or particles) can pass through and $0$ where they cannot). The intensity is then just the square magnitude of the amplitude.
Thus, for a single slit (a rectangle) then the aperture function $h\left(x,y\right)=\Pi\left(x/w\right)\Pi\left(x/h\right)$ the intensity of the interference pattern is:
$$I\propto\operatorname{sinc}^2\left(\frac{1}{2}wk\sin\left(\theta\right)\right)\operatorname{sinc}^2\left(\frac{1}{2}hk\sin\left(\phi\right)\right)$$
where $\Pi\left(x\right)$ are Rectangular functions ("top hat functions"), $w$ and $h$ are the width and height of the slit, while $k\equiv\frac{2\pi}{\lambda}$ where $\lambda$ is the wavelength and finally $\theta$ and $\phi$ are the angles in the $x$ and $y$ directions to the normal. We can approximate $\sin\left(\theta\right)=\frac{x}{L}$ and $\sin\left(\phi\right)=\frac{y}{L}$ when close to the centre of the interference pattern.
For a double-slit we get an extra factor of $\cos^2\left(\frac{1}{2}Dk\sin\left(\theta\right)\right)$ where $D$ is the slit separation so:
$$I\propto\operatorname{sinc}^2\left(\frac{1}{2}wk\sin\left(\theta\right)\right)\operatorname{sinc}^2\left(\frac{1}{2}hk\sin\left(\phi\right)\right)\cos^2\left(\frac{1}{2}Dk\sin\left(\theta\right)\right)$$
I recommend plotting these equations (replacing $\sin\left(\theta\right)=\frac{x}{L}$ and $\sin\left(\phi\right)=\frac{y}{L}$) using plotting software (for example Desmos) and tweaking the parameters to see how this affects the interference pattern. You should find as the slits get longer there appears to be no variation vertically, as the slits get narrower then in the double-slit experiment the intensity drops off less slowly.
Finally, for a circular hole, we will get Airy disks (the Wikipedia page linked has some nice images of diffraction patterns).
Comment: Any circular aperture (a lense can also be viewed as a magnifying component and a circular aperture) will in the Fraunhofer regime produce Airy disks. However, the ratio of the wavelength to the aperture size sets the scale of the diffraction pattern and so for large apertures only the central maxium will be visible so the interference pattern apears to vanish but as the apeture gets smaller more and more fringes can be seen.
Comment: Thank you so much! Regarding the lens question, I did not mean (and maybe I should have clarified that) the pattern due to diffraction from a circular aperture, but just interference from two plane waves using an interferometer for example. Why doesn't a lens focusing the light make this "Airy pattern" also?
Comment: In regards to the shape pattern observed in an interferometer see this section on Wikipedia: https://en.wikipedia.org/wiki/Michelson_interferometer#Configuration specifically figure 3 which shows how tilting the mirrors will change the interference pattern and the text describes how the fringes are conic sections.
Answer: If the slits are vertical, the light will diffract left and right, creating a horizontal pattern.


How do you add a fillet (bevel/bridge) between two complex shapes?

Question: Blender Noob here, so forgive the simple question. I've searched high and low to find out how to emulate Fusion360's "rolling ball" fillet between two objects and can't seem to find any reasonably easy way to do this. I've seen an explanation using added loops and bridging the loops, but that becomes nearly impossible with anything other than really simple shapes and really simple intersections. The basics of what I want is shown in the image below.

How do I put a fillet between an angled cylinder intersecting with 3 faces of a cube? Bevel seems like it should do it, but after 10 or more attempts with various methods, I've had no luck.  There are 3 arcs that I just want to tell Blender "bevel, 6 segments, 2mm width." But every attempt creates awful geometry. There must be a simple way. I believe I need to start by joining the two objects...or doing a Boolean Difference to create the intersection geometry. In Fusion360, this is a 2 minute task. Is there an easy way to do this in Blender?
Thanks in advance.
Answer: 2 add-ons. 1) MeshMachine (Paid) or 2) Bevel after Boolean (Free). Or you will have to learn topology and choose the number of vertices and the placement of 2 meshes wisely for further topology cleanup so that it's an all (or almost) quad based geo which in turn helps in adding those fillets. OR you can add bevel in render (but very small bevels) using the bevel node.

Edit:-
Comment: I think I understand your quad geo approach and tried to emulate your steps, but am getting stuck at the actual fillet.  I created a cube, low-facet cylinder, Boolean Diff'd the cube from the cylinder to get the edges and vertices at the object intersections. Then I joined them as it appears you did. I then added edge loops slid to the vertices of the intersections and created the quad faces.  But now that I have edges defined where I want fillets, if I select those edges and apply a fillet, it's beveling the end of the cylinder and not creating a rounded fillet between the cube and cylinder.
Comment: It's an Addition Boolean not a Difference Boolean. When You Add both the structures, you are able to join the vertices of both the meshes plus there are no extra "inner" faces involved. Your geometry (i suppose) has extra face from the square.


What does it mean to "labour to enter that rest" in Hebrews 4:11?

Question: What did the book of Hebrews mean in 4:11:

Let us labour therefore to enter into that rest...KJV
Comment: 1st, the book of Hebrews has nothing to do with the Hebrew bible. The tag is wrong. 2nd, what is "laber"? Did you mean labour/labor ?
Comment: Related: "[What is the meaning of 'Rest' in Heb. 4:3-5?](https://hermeneutics.stackexchange.com/questions/16851/)"
Answer: Scripture links rest to Sabbath. The term Sabbath is linked to the giving of the Law. Before then, it was a blessed and sanctified day as God rested from His work (Gen 2:2-3) but there was no requirement yet laid on mankind to rest.
The Sabbath given to God's people from the giving of the Law to Christ's death was a rest on the 7th day, namely Friday evening through to Saturday evening. This was a "shadow" or "type", a taste if you will of the real rest in the heavenly. But until Christ said "it is finished" the Father was still working.
    "My Father is working until now, and I Myself am working." John 5:17
When Christ completed His work He fulfilled the requirements of the Law including that of the Sabbath. The believer then who trusts in Him has a Sabbath rest available at all times;
    "For we who have believed enter that rest" Hebrews 4:3.
Believers are seated with Him in heavenly places. God has ceased from His work of salvation.
    "For the one who has entered His rest has himself also rested from his works, as God did from His." Hebrews 4:10
The greek word used is spoudázō which means to make haste, to give diligence. It is rendered "labour", "diligence", "give effort", etc in English translations. We can accept either diligence or labour as both imply effort.
Our example of entering rest is that of Joshua and Israel entering their Canaan rest, another type and shadow. As they did, so we will come up against the enemy within and the enemy without. For Joshua this represented the inhabitants of the land: Canaanites, Amorites, etc and foreign attackers such as Midian, Edom, Moab, Aram, etc. For us this means the old man, sinful actions, habits, strongholds, etc. as well as our adversary the devil.
Our labour is to put to death the old man and send the enemy to flight through seeking God, taking up our cross, renewing our mind with the word of God, following Christ, being led by the Holy Spirit, spiritual warfare, etc. These exercises are how we are diligent, earnest or labour.
By so labouring we then enter into our rest. Every day we should come into our Father's presence in the name of Christ Jesus our Lord. This pattern is according to the heavenly as God is at rest having completed His work. It is therefore no longer just one day in the week. For that is the pattern of the old. Jesus' new Sabbath is a permanent rest where we are to walk in the fullness of Christ all the time.


Is Quantum Physics used in manufacturing CPUs?

Question: If I remember correctly, I heard some people saying that the transistors on CPUs today are so small, that they have to use quantum physics to make CPUs. Is that correct?
Answer: Quantum mechanics is part and parcel of understanding the function of any transistor, and therefore any integrated circuit.
As component sizes have gotten smaller, tunneling has become an increasingly important limiting factor in the design and layout of chips.
Answer: Well, they are not using it, but taking into account.
Tunneling is one of the most important:
1) As gate oxide thickness is just 1-2nm, electrons can tunnel through it -> power consumption increases (or transistor might turn itself on if gate is not connected at the moment). So if you replace usual SiO2 with high-K dielectric (like HfO2) you would be able to increase gate oxide thickness (=dramatically reduce tunneling) but electromagnetic field will remain the same (i.e. transistor would work exactly as with thin oxide)
2) Flash memory directly rely on quantum tunneling effect - electrons into strong electromagnetic field tunnel right into middle of dielectric, and form 'trapped' charge, which may stay there for years.
Comment: @blah CPU design teams will be hundreds strong. There will be levels of CPU designer that are not much concerned with transistor details, but there will be other levels of CPU designers that are intimately concerned with quantum mechanics.
Comment: CPU designers is a general term. Logic designers probably don't even remember how a diode works (at least they don't need to), on the other hand wafer designer have to know the implications on choosing different materials.
Comment: I like how you said "they are not using it, but taking into account." I doubt CPU designers need to thoroughly understand the physics behind transistors and such, but they'd probably need to know how to put these pieces together into a functional CPU.
Comment: CPU designers surely does not care about it. But engineers working on tech.processes & libraries - they have to think about it. But these guys are really rare.
Answer: There will be several teams of CPU designers - Logic Designers, Logic Implementation, Data Integrity, Data Storage, Data Transmission, materials research and then a management team. logic implementation will most likely have physics specialists who advise on a plethora of issues. They would be expected to look at new designs and decide whether the implementation would fail due to the physical constraints and effects of the materials they use. They have to have a firm grasp of all aspects of microelectronic physics - Thermodynamics, Quantum Physics, Electromagnet effects etc. things like alteration of electron speed as it passes through different materials has to be considered so data arrival times are consistent. It is very likely that that the CPU Caches use Quantum Tunnelling for data retention, and the  Cache blocks are probably kept seperate from the Transistor arrays to minimise quantum interference.
Answer: Otherwise instead of "fight" these phenomena, like tunnelling, you can think a new solution :
From http://en.wikipedia.org/wiki/Quantum_computer

A quantum computer is a device for computation that makes direct use
  of quantum mechanical phenomena, such as superposition and
  entanglement, to perform operations on data.

On the Wikipedia page you can see the photograph of a chip constructed by D-Wave Systems Inc., designed to operate as a 128-qubit superconducting adiabatic quantum optimization processor.
I am not an expert, I understand that quantum computing can be explained as :

put in the N input data as a physical quantity of the system,
repeated N times
let's the physical system evolves and finds its natural quiet
state
measure the N new values of the chosen physical quantity : this
set is a possible solution of the problem ( and reading it is also the most
challenging task )
repeat from 1. until you find satisfactory output data sets

For certain classes of problems, quantum computing seems to be the best path to solve them.
An example, solving a classical search problem - see the demo on the marvellous Wolfram web site :
http://demonstrations.wolfram.com/QuantumComputerSearchAlgorithms/


Visual C++ executable and missing MSVCR100d.dll

Question: I know this has been asked in other places and answered, but I'm having issues with MS Visual Studio 2010. I've developed a C++ executable but if I run the Release version on a machine that doesn't have the VC++ runtime library (ie, msvcr100d.dll), I get the "program cannot start because msvcr100d.dll is missing from your computer" error.
This is weird for two reasons:

Why is it trying to link with the debug version of the redistributable?
I tried applying this fix, setting the runtime library setting to /MT instead of /MD (multi-threaded DLL), but that only made the problem worse (if I manually copied msvcr100d.dll, it then said it couldn't find msvcp110.dll).

How can I package the runtime library with my executable so that I can run it on machines that don't have MS VC 2010 or the redistributable installed?
I know it's considered a security risk to include a copy of the DLL since it won't ever be updated, but my goal is just to send this executable to a few friends in the short term.
Comment: What do you mean by using the `/MT` setting made things worse?  That should remove the dependency on the DLL runtime.  Does your project depend on other DLLs?  They might be what is improperly depending on the debug runtime.  A utility like Dependency Walker can help you figure out if that's the case: http://www.dependencywalker.com
Comment: @MichaelBurr Dependency Walker confirmed that one of the DLLs my project depends on does depend on msvcr100d.dll. Turns out that DLL wasn't building in Release mode. Thanks.
Comment: @eli: I don't think people really care much about the security risk when they tell you not to redistribute the DLL, since you can link statically anyway. It's more of a licensing issue than anything else.
Comment: Just because of this problem, I shifted my project to VS 2008 and Win 7 already had its prerequisite dlls.
Answer: You definitely should not need the debug version of the CRT if you're compiling in "release" mode. You can tell they're the debug versions of the DLLs because they end with a d.
More to the point, the debug version is not redistributable, so it's not as simple as "packaging" it with your executable, or zipping up those DLLs.
Check to be sure that you're compiling all components of your application in "release" mode, and that you're linking the correct version of the CRT and any other libraries you use (e.g., MFC, ATL, etc.).
You will, of course, require msvcr100.dll (note the absence of the d suffix) and some others if they are not already installed. Direct your friends to download the Visual C++ 2010 Redistributable (or x64), or include this with your application automatically by building an installer.
Comment: installing Microsoft Visual C++ 2010 SP1 Redistributable Package (x86) worked great for me!
Comment: @Joseph that should only apply to the release version since (as Cody Gray mentioned) debug versions are usually not redistributable. If you don't have MSVC2010 installed, `msvcr100d.dll` should still be missing.
Comment: Those links no longer work :-/
Comment: Google for the name, @Ignorante. It's trivial to find them.
Comment: Well, I did find them, but not in microsoft site. Apparently they no longer have them there. That's why I commented.
Answer: For me the problem appeared in this situation:
I installed VS2012 and did not need VS2010 anymore.
I wanted to get my computer clean and also removed the VS2010 runtime executables, thinking that no other program would use it.
Then I wanted to test my DLL by attaching it to a program (let's call it program X).
I got the same error message.
I thought that I did something wrong when compiling the DLL.
However, the real problem was that I attached the DLL to program X, and program X was compiled in VS2010 with debug info. That is why the error was thrown.
I recompiled program X in VS2012, and the error was gone.
Answer: This problem explained in MSDN Library and as I understand installing  Microsoft's Redistributable Package can help.
But sometimes the following solution can be used (as developer's side solution):
In your Visual Studio, open Project properties -> Configuration properties -> C/C++ -> Code generation
and change option Runtime Library to /MT instead of /MD
Answer: Usually the application that misses the .dll indicates what version you need – if one does not work, simply download the Microsoft visual C++ 2010 x86 or x64
from this link:
For 32 bit OS:Here
For 64 bit OS:Here
Answer: I got the same error.
I was refering a VS2010 DLL in a VS2012 project.
Just recompiled the DLL on VS2012 and now everything is fine.
Answer: Debug version of the vc++ library dlls are NOT meant to be redistributed!

Debug versions of an application are not redistributable, and debug
  versions of the Visual C++ library DLLs are not redistributable. You
  may deploy debug versions of applications and Visual C++ DLLs only to
  your other computers, for the sole purpose of debugging and testing
  the applications on a computer that does not have Visual Studio
  installed. For more information, see Redistributing Visual C++ Files.

I will provide the link as well : http://msdn.microsoft.com/en-us/library/aa985618.aspx


How much escrow/ Multi-signature transactions are done?

Question: I have read here about the possibility of Multi-signature transactions. Is there a statistic available how much of these are done?
Answer: Blockchain doesn't currently offer that and the only way to construct a transaction like that is to build it manually.  So as a result both the sender and each recipient must have l33t skills.
This capability will come, it is just that since that was introduced, scalability had to take priority over new features for most Bitcoin development.
They happen but rarely.  Here's an example of Bitcoin address used recently (March 5, 2013) in an escrow transaction:
,- http://blockchain.info/address/13MH4zmU4UT4Ct6BhoRFGjigC8gN9a9FNn
Answer: Here is nice statistics http://webbtc.com/stats of different script type
Comment: But not how many multi-signature transaction, or am I missing something?
Comment: Do you want the number if msig outputs? 87477 right now. Or are you looking for the number of multisignature scriptSigs in the blockchain? In other words: fundings or spendings?
Answer: I wrote some analysis of the multisig P2SH transactions in the blockchain; http://www.coindesk.com/year-multisig-so-far/ Around April this year there were like 7,000 transactions. I have the frequency per 2500 blocks, showing a nice histogram of their increasing usage, and also the top 4 address types (2-of-3, 2-of-2, etc).


why can't the missing mass (evidence for dark matter) be matrioshka brains/dyson spheres?

Question: i know that the claim is that nucleosynthesis models say that the observed abundance of deuterium is too high for dark matter to be baryonic, but couldn't deuterium be a waste product of civilizations?  you say that postulating civilizations is not the simplest explanation, but isn't it far more complex to postulate that we are unique (or an invisible form of matter with exotic physics for which we have no evidence)?  even from a single seed civilization, galactic colonization times are in the hundred million year range, so we should expect some evidence of environmental manipulation everywhere we look.  given the need for civilizations to hide from predators, isn't eliminating EM interactions/emissions the best strategy?
Comment: Is this really about physics? I can see why it's a valid question, and I can see there's physics behind it, but is the question itself about physics?
Comment: @Bruce: agree. The question is half (or more)-way leaning towards sci-fi.
Answer: Physically, if you look at the low level of CMB anisotropy and the BAO power spectrum, you need some sort of mass that interacts gravitationally but is decoupled from the photons before recombination (i.e. - dark matter). Otherwise there would be no way to seed the galaxy formation that we see occuring at lower redshifts. That is to say, dark matter needs to be primordial, so that it can dodge Silk Damping and provide the graviational "cores" around which galaxies form.
Which would also imply that dark matter cannot be the construct of an alien civilization.
Comment: "The question is half (or more)-way leaning towards sci-fi" at least physics can explain it!
Comment: Also, the dyson spheres would have to radiate at a T>cmb in order to expel waste heat.
Answer: I might be talking non sense, but I'll try arguing with your logic. (Is there any physics to be answered in there?)
You're doing a lot more than just postulating civilization.

You're postulating they are on every single galaxy where dark matter effects have been found. (I'm no astrophysicist, but I believe dark matter effects have been verified on every single galaxy where we've looked.)
You're postulating they reached a stage of galactic colonization, (again) on every single one of these cases. Note that if this stage really is on the range of 100 million years (which seems to be pure speculation on your part) than it is so small compared to the age of galaxies. Considering the number of galaxies we've looked at, we should have found some that are not colonized "yet" (Statistically speaking).
Not to mention, where did they get all the matter for that? Isn't dark matter density 3 times higher than ordinary matter density?
Answer:
Typical Drake equations yield 100s of societies per galaxy.  Most probably end tragically but it would only take 1 to colonize a galaxy.  There has been enough time to colonize all(indeginous or cross galaxy).
Life grows exponentially and we have only characterized the dark matter in a fraction of the universe.  Perhaps all have been colonized, or the tiny galaxies too small to generate successfully life or too far to colonize yet have not been observed.  This is a testable hypothesis:  we will find tiny, isolated galaxies without dark matter.
Imagine a pre colonized galaxy with denser and sparser regions.  The least time and energy to colonize would be going from densest to densest region.  Another testable hypothesis:  dark matter is lumpy, continuous, and a different fraction per galaxy.  Some may be far more than 3x and others less.
As it stands now no model of physics explains the data.  Evolution works in the opposite direction of entropy (netting to a loss but there is no shortage of mass,  energy and time to play with before the heat death).
Comment: "There has been enough time to colonize all(indeginous or cross galaxy)." From the vantage point of the hear and now, maybe our galaxy. But when we peer out, we are peering at earlier parts of the universe. As such there were fewer supernova to have fused heavy elements to have combined and evolved into intelligent life.
Comment: "Evolution works in the opposite direction of entropy"
Evolution is an ordering of of more and more complex information. A proper accounting should consider evolutionary dead ends, and the solar input. Such a system might then, to a degree, resemble an air compressor and a leaky tank powered by solar cells. Remove the power source and evolutionary complexity will devolve back to single cells eaking out what little energy they can until all energy potential is spent.
Comment: Hypothesis 2: Dwarf galaxies appear to be dominated by dark matter.
Answer: "So even if every star in the universe had a dyson sphere around it, that would add up to, about, 110% of the regular matter we measure, but it needs to be >600%"
Great point. If dyson spheres were around several stars though, would they obscure the light and thus lower the amount of stars we are actually estimating? It's not so much the DS material itself that consists of the gravity of dark matter, it is of those stars hidden within the dyson spheres we are not accounting for.
Comment: Why would all the dyson spheres be distributed differently to the stars we can see? Mass does not follow light in galaxies.


If in a given topological space X every set $ \{x\}, x \in X, $ is open, is then $X$ discrete

Question: If in a given topological space $X$ every set $$ \left\{x\right\},   x \in X, $$ is open, is then $X$ discrete? My question is this:  is an infinite union of open sets open? Or is it only valid for a countable union?  I get that the definition of a discrete space is that every subset is open, but does it go the other way?
Comment: Yes. Every union of open sets is open. It's in the definition of the topology. And yes, discrete $\Longleftrightarrow$ every set is open.
Answer: Yes, by the definition of topology an arbitrary union of open sets is open.
In particular, if each singleton is open all sets are open and the topology is discrete.
Answer: The answer is positive: $X$ is discrete, once very set $Y=\{a,b,c,...\}$ can be formed as an union of open sets $\{a\},\{b\},...$- and, therefore, is open. And yes, infinite- countable or not!- unions of open sets are open. Only intersections are required to be finite in the definition of a topology.
Answer: If every singleton is an open set the topology is discrete. Indeed, every subset of the topological space is open (this follows from the definition of topological space) and this is the definition of discrete topology.


Difference between PowerPivot, PowerQuery and PowerBI

Question: What is the difference between

powerpivot,
powerquery
and powerbi?

What are the use cases for each tool?
What are the limitations?
What requirements must be met to use the tool?
Comment: Reading [PowerPivot](https://stackoverflow.com/tags/powerpivot/info) it sounds that it is similar to  [Power Pivot for Sharepoint](https://learn.microsoft.com/en-us/analysis-services/power-pivot-for-sharepoint-ssas) but [tag:powerpivot] is a `part of the Microsoft Business Intelligence suite` and can be used indepentently from  `Power Pivot for Sharepoint`. What does the [`End of Life` for the sharepoint "version"](https://learn.microsoft.com/en-us/analysis-services/power-pivot-for-sharepoint-ssas) mean for the [tag:powerpivot]  Business suite product?
Answer: Power Query
Power Query is a self-service ETL (Extract, Transform, Load) tool which runs as an Excel add-in.  It allows users to pull data from various sources, manipulate said data into a form that suits their needs, and load it into Excel.
Power Pivot
Power Pivot is an in-memory data modelling component that enables highly-compressed data storage and extremely fast aggregation and calculation.  It is also available as part of Excel, and can be used to create a data model within an Excel workbook.  Power Pivot can load data itself, or can have data loaded into it by Power Query.  It is extremely similar to the SSAS (SQL Server Analysis Services) Tabular model, which is like a server-based version of Power Pivot.
Power View
Power View is an interactive visualisation tool which provides users with a drag-and-drop interface allowing them to build quick and easy visualisations of the data in their Excel workbooks (using the Power Pivot data model).
Power BI
Power BI is a SaaS service which enables business users to service their own business intelligence needs. It provides built-in ability to connect to SaaS services like Salesforce and many others.  It provides connectivity to on-premises and cloud sources using a combination of direct query and periodic data refreshes. It is available as a freemium service. It is the successor to 'Power BI for Office 365' that was based on Microsoft's Office 365 and SharePoint Online products, and, through Excel 2013, encompasses Power Query, Power Pivot, and Power View.
Power BI (with O365 and SharePoint Online) provides a site where users can upload and share their created content with other users, as well as manage gateways into enterprise data source, enable data refresh, and advanced features like Q&A, which allows natural language querying of data models.
Microsoft has also released a standalone Power BI Desktop application, which ties together Power Query, Power Pivot, and Power View in a standalone application, removing the Excel 2013 constraint. Power BI Desktop is available for free.
It is also possible to achieve a lot of the functionality of Power BI using on-premise SQL Server 2012+, Excel 2010+ and SharePoint 2010+, if cloud-based is not an option for you.
Comment: There is also now PowerBI Embedded which allows embedding of PowerBI reports in web applications without the need for PowerBI accounts for end users
Comment: Microsoft have now released on On Premise Server version of Power BI.  This gives the ability to have complete sovereignty over your data.  It works pretty wll but does not make possible Natural Language Query.
Comment: Excel no longer requires an addon to use power query, it's built in. Some versions call it `get data`.
Answer: Simple answer:

PowerBI=PowerQuery+PowerPivot+PowerView

Alternate answer:
If

[PowerQuery]="Clean Data/M language" and [PowerPivot]="Calculations/DAX language" and [PowerView]="Data visualization"

then

[PowerBI]=concatenate ("PowerQuery","-","PowerPivot","-","PowerView")

else "Excel"

Hope this answers the question :)
Answer: Power View
is an interactive data exploration, visualization, and presentation experience that encourages intuitive ad-hoc reporting. Power View is a feature of Microsoft Excel 2013, and of Microsoft SharePoint Server 2010 and 2013 as part of the SQL Server 2012 Service Pack 1 Reporting Services Add-in for Microsoft SharePoint Server Enterprise Edition.
Power Map
for Excel is a three-dimensional (3-D) data visualization tool that lets you look at information in new ways. A power map lets you discover insights you might not see in traditional two-dimensional (2-D) tables and charts.
Comment: Both Power Map & Power View are based on a Power Pivot data model, but they're not the same. Power View is not limited to maps but does not have 3D maps. Note: Power View is pretty much deprecated in Excel 2016 & higher and is no longer in active development.
Comment: According to my course, *Power Map*  visualizes geospatial data from a PowerPivot Data Model. That does not sound as the same. Can you clarify?
Answer: I like both answers from GShenanigan (tools breadown) and excelislife (simple answer).  But I will merge them all into my own synopsis to provide an updated definition as of 2018 November.
What is Power BI?
Simple answer: PowerBI=PowerQuery+PowerPivot+PowerView
If
[PowerQuery]="Clean Data/M language" and [PowerPivot]="Calculations/DAX language" and [PowerView]="Data visualization"
then
[PowerBI]=concatenate ("PowerQuery","-","PowerPivot","-","PowerView")
else "Excel"

Another perspective of the PBI Tools
I have removed Power View, because I do not think this is relevant anymore.  It was a canvas sheet for building visualizations (charts, maps, graphs, table), but now this is done in PBI Desktop.

Power Query
Users connect to a data source and build a data set. Drag-and-Drop
interface to build ETL steps with the ability to also write custom
code (Language: M).  Data is loaded to Excel table or PowerPivot data
model.  NOTE: There are a variety of "connectors" for accessing many
different data sources.  To name a few: Database tables (SQL
Server/Oracle/SSAS...), ODATA Feed, SaaS services
(Salesforce/Exchange/…), Files (text/csv), and more.
Power Pivot
Users import data sets and build a data model.  Measures are Calculations/Aggregations
(Language: DAX).  Report visuals are built off of the data model (DATASETS +
RELATIONSHIPS + MEASURES)
using the PowerBI visualizations canvas.
Power BI
PowerBI Desktop, or Excel, is where you build the reports (charts,
maps, graphs, table). PowerBI uses the PQ and PP steps to get the
data.
There are few ways to share these reports as seen on this blog post, "PBI 15 ways to
share", https://blog.coeo.com/power-bi-15-ways-to-share-data.  Here
are the most relevant for enterprise collaboration based upon my
experience.

PBI Service  Deploy Power BI reports to the service,  https://app.powerbi.com/. These are overarching visualizations of a business overview, created by pinning visualizations from one or many reports. You publish dashboards inside and outside your organisation by hitting the share button when viewing the dashboard. Recipients of the share require a Pro licence (you pay per user per Month), or you deploy the content to premium capacity. You can configure the ability for internal recipients to re-share during the sharing process. Re-sharing can also be turned off completely in the Power BI admin portal.
On-Premises Report Server  Deploy Power BI reports alongside paginated SSRS reports.
Embed - App Owns Data  Embedded within third-party applications, requires no authentication by the end-user to Power BI.
Share PBIX  The PBIX file is open by the users in the development environment (PBI Desktop). On-premises and free, no PBI
Pro license required.
Export to Excel or CSV  Click the ellipses on the top right of a visualization and select "export data".

Hope this helps!
Answer: Power BI: Power BI is a Business Intelligence and Data Visualization tool which helps you to convert data from the various data source into interactive dashboards and BI reports. It provides multiple software connectors and services.
Power Query: It allows you to discover, access, and consolidate information from different sources.
Power Pivot: A modelling tool.
Power View: It is a presentation tool for creating charts, tables, and more.
Power Map: Helps you to create geospatial representations of your data.
Power Q&A: This allows you to use natural language to get answers to questions.
Answer: power bi is a visualization and business intelligence platform that can run power query and power pivot inside.
power query basically helps you to get data from different sources and automatize.
power pivot is a data modeling tool


CPU,Memory and disk I/O utilization for each query in mysql

Question: How can we identify the exact CPU,Memory and disk I/O, when a query is executed. I am using mysql 5.7.20 community version. I am able to get only cpu details for session level by setting SET profiling=1. How can we identify all these details in global level for all the sessions.
Answer: Using IOTOP command you can see CPU,Memory and disk I/O utilization for each query. For each query mysql generates an ID. You can find CPU,Memory and disk I/O utilization against your query ID.
How ever you may find more command in detail at http://www.dbatodba.com/db2/useful-aix-commands/monitor-cpu-mem-and-i-o-usage/
SET profiling = 100
-- Now you can find query ID and running sql query by
SHOW PROFILES; IF you want TO CHECK IN detail FOR ANY QUERY, run this QUERY-
-- SHOW PROFILE FOR QUERY QueryID;
-- If you want to check CPU USAGE for any query, run this query-
SHOW PROFILE CPU FOR QUERY QueryID;
Comment: Thank for information pankaj kumar. My doubt is does mysql stores these information in any tables or views?? Lets take an example I have ran a query before two days. How can I get the details like how much memory been utilized for the query when I had executed it.
Comment: SHOW PROFILES displays a list of the most recent statements sent to the server. The size of the list is controlled by the profiling_history_size session variable, which has a default value of 15. The maximum value is 100. Setting the value to 0 has the practical effect of disabling profiling.
Optional type values may be specified to display specific additional types of information:
Comment: -- ALL displays all information
-- BLOCK IO displays counts for block input and output operations
-- CONTEXT SWITCHES displays counts for voluntary and involuntary context switches
-- CPU displays user and system CPU usage times
-- IPC displays counts for messages sent and received
-- MEMORY is not currently implemented
-- PAGE FAULTS displays counts for major and minor page faults
-- SOURCE displays the names of functions from the source code, together with the name and line    number of the file in which the function occurs
-- SWAPS displays swap counts
Comment: Now set maximum profiling
SET profiling = 100
Now you can find query ID and running sql query by
 SHOW PROFILES;
If you want to check in detail for any query, run this query-
 SHOW PROFILE FOR QUERY QueryID;
 If you want to check CPU USAGE for any query, run this query-
 SHOW PROFILE CPU FOR QUERY QueryID;
Answer: Memory usage -- InnoDB has a common "buffer pool" where it caches blocks.  there is no metric for memory usage.  On the other hand, you can find out various statistics for all queries over a period of time by watching the STATUS values of Innodb_% grow.
For CPU time, I recommend turning on the "slowlog" with long_query_time=0.  That will rapidly fill disk with lots of details about every query, including the elapsed time.  Note that "elapsed" is more interesting that CPU vs I/O.
The slowlog gives you the best view into which queries you should work on improving.  Perhaps that is what you are really looking for?  Use either pt-query-digest or mysqldumpslow -s t to find the few "worst" queries.  More discussion:  http://mysql.rjweb.org/doc.php/mysql_analysis#slow_queries_and_slowlog
Comment: @ToolmakerSteve - Yes, any other activity can impact the elapsed time.  If your CPU has 8 cores, you need 9 things running for that to have much effect.  If other queries are touching the same rows, etc, then locks can block one or the other.
Comment: @ToolmakerSteve - If you have a slowlog covering 1000 instances of a particular query, nearly all will have about the same elapsed time.  But a few may take 10 times as long.  If, for example, long_qiuery_time = 1 (second) and that query normally takes 0.2 sec, a _few_ instances of those 1000 will show up in the log.
Comment: Re *"'elapsed' is more interesting than CPU vs I/O"*.  Question: When there are multiple active connections on a server, will "elapsed" time depend on server load? Do I need to test during a quiet period, to get an accurate sense of the cpu time actually consumed by each query?  I'll test it both during busy and quiet times, so I'll know then, but I thought it would be good for others to know "a priori" what "elapsed time" really measures.


Exodus 19:13 - come near or go up on the mountain?

Question: Is the meaning of the Hebrew text closer to "go up on the mountain" (e.g. NRSV) or "come near the mountain" (e.g. NKJV)?
Answer: The verb יַעֲל֥וּ is the Qal imperfect 3rd person masculine plural jussive of עלה.
The meaning of the Qal is to assend, go up.

עלה
qal ... —1. a) to ascend, go up ... —2. to make one's way up ...
Koehler, L., Baumgartner, W., Richardson, M. E. J., & Stamm, J. J. (1994–2000). In The Hebrew and Aramaic lexicon of the Old Testament (electronic ed., p. 828). E.J. Brill.

Some have trouble translating it this way because of the context.  Thus, either:

God is telling them they can come up the mountain after the trumpet blast but not before. (The most straight forward interpretation) (Deut. 5:4-5 seems to support this interpretation),

Or,

They are to come up near the mountain after the trumpet blast  (The interpretation that seems to fit the context better, but an awkward way of translating the Hebrew.)

The preposition ב doesn't help. In the mountain doesn't make sense.  It is not ל to the mountain, or על on the mountain.
Commentary
Agrees with 1:

they may go up Sinai possesses no inherent or "natural" holiness, nor does it acquire such by virtue of the theophany. Its sanctity and hence untouchability do not outlast the limited duration of the event. See Comment to 3:5.
--
Sarna, N. M. (1991). Exodus (p. 106). Jewish Publication Society.

The idea of explicitly sacred (Heb. kadosh) space is encountered here for the first time. No such concept exists in Genesis, which features only sacred time—the Sabbath. The pagan mythological notion that certain areas are inherently holy does not exist in the Bible. It is solely the theophany that temporarily imparts sanctity to the site, rendering it inaccessible to man.
-- Ibid., p. 15.

Use of בָהָֽר in the Tanak (Hebrew Old Testament)
"On the mountain/Mount" dominates for בָהָֽר although not exclusive.  Not mentioned is בָהָֽר is often translated "in the hills/hill country" in Genesis although the Hebrew is singular.
Gen. 22:14 on the mountain
Exodus 4:27 at the mountain
Exodus 15:17 on ... mountain
Exodus 19:12 into the mountain ... the mountain
Exodus 19:13 to the mountain
Exodus 24:18 on the mountain
Exodus 25:40 on the mountain
Exodus 26:30 on the mountain
Exodus 27:8 on the mountain
Exodus 31:18 on Mount
Exodus 34:32 in Mount
Leviticus 7:38 on Mount
Leviticus 25:1 on Mount
Leviticus 26:46 on Mount
Leviticus 27:34 on Mount
Numbers 3:1 on Mount


Filenot found error when i run with site guest user license on the debug log

Question: We have a force.com site which we are in the build process. When i run the home page of the force.com site and click on a button to go to my visual force pages, i am getting a file not found error on the debug log. I turned on debug log for the guest site user license for my site and i am not getting any debug outputs at all. My site is here
http://peakdevint.devint.cs15.force.com/ I have attached a screen shot of the issue.Could you guys let me know what could be the reason for this and how do i get my debug output for the log?
Comment: +1 for including the _actual_ site URL in your question, it helps!
Answer: There are two assets on your site which don't exist. When these assets are requested, Salesforce serves FileNotFound.page as a response (hence filling up your Debug Logs).

http://peakdevint.devint.cs15.force.com/css/application.css
Line 15: <link href="css/application.css" rel="stylesheet" type="text/css" />
http://peakdevint.devint.cs15.force.com/js/libs/modernizr-2.0.6.min.js
Line 17:


Asus P10S-C/4L won't get past Q Code 62 with Intel E3-1220 v6 and 8GB of DDR4 2400 ecc

Question: Upon power up, the Asus logo appears on screen and the Q Codes change as it moves through the boot procedure until 62 is reached where it gets stuck and stays until I reset or power off. I have sent an email to Asus but they have not replied and I was wondering if anyone could point me in the right direction? I have looked up the Q Code in the manual and it means SB run time init which I have no clue to what it is about.
Any help would be greatly appreciated
Answer: Оn the motherboard (Asus P10S-C/4L) there is a sticker with the BIOS version
For example, I have 0506 BIOS version. But Intel Xeon E3-1220 V6 compatible with 3104 BIOS version. I have same problem - q code 62.

Use CPU support table
https://www.asus.com/Commercial-Servers-Workstations/P10S-C-4L/HelpDesk_CPU/
Install the processor that is compatible for your BIOS version.
For example, I use Celeron G3900
Then Download Latest BIOS and update CPU MicroCode with ezFlash tool.

Good luck.
Answer: Q Code 62 usually has to do with GPU issues.  Please ensure the following:

GPU is seated correctly (you may want to pull the card and re-seat it)
Power cables for the GPU from the power supply are plugged in fully
If you can get to your BIOS, look in there and make sure the 3.3, 5, and 12v readouts are correct (you want all of the values to be fairly close to the stated numbers).


Issue with securing RTMP streams from Level3 CDN

Question: I am currently dealing with securing rtmp streams from Level3 CDN.
The documentation can be found here:
https://rapidshare.com/files/1450549534/Token_Components.html
(looks like you need to be logged in to view, therefore i re hosted on rapidshare. the original url is:
https://mediaportal.level3.com/mediaWeb/help/Content/ServicesDocs-Streaming/StreamingTokenAuth/TokenComponents.htm )
Scoll down to On Demand Streaming Input / Output Example ( For MP4 Files )
I am trying to reproduce the example and to get the same url with the same values. I wrote a little function for that:
function flimmithash($file) {
    $streamer = 'pmsales';
    $host = 'pmsalesfs.fplive.net';
    $start_time = '20080101120000';
    $end_time = '20101231235900';
    $customer_secret = 'Secret'; // in the documentation there is also secret with a non capital s, i tried both

    $resouce_path = "/$streamer/$file";                                                     echo "resouce_path: $resouce_path
\n";
    $message = "$resouce_path?start_time=$start_time&end_time=$end_time#$customer_secret";  echo "message: $message
\n";
    $digest = md5($message);                                                                echo "digest: $digest
\n";
    $tokenvalue = "start_time=$start_time&end_time=$end_time&digest=$digest";               echo "tokenvalue: $tokenvalue
\n";
    $token = base64_encode($tokenvalue);                                                    echo "token: $token
\n";
    $url = "rtmp://$host/$streamer?token=".($token)."/mp4:$file";                           echo "url: $url
\n";
    return $url;
}
echo "url: ".flimmithash('support/lvlt300kbps.mp4')."
\n";

I use the exact same values as in the example but just cannot get the same digest.
I used md5, because it matches the length. I also tried secret with capital and non capital s.
You can go to sample scripts here: https://rapidshare.com/files/2581196874/Appendix.html (Original: https://mediaportal.level3.com/mediaWeb/help/Content/ServicesDocs-Streaming/StreamingTokenAuth/Appendix-SampleScripts.htm )
But there is absolutely no md5 used, they use sha1. But sha1 is longer then the digest from the example.
Of course I tried to populate both versions with my values, but neither worked.
So my question is: Can anybody reproduce the example and/or tell me the digest or alter my function to work according to the example?
Comment: You could try all of [hash_algos](http://php.net/manual/en/function.hash-algos.php) with [hash](http://www.php.net/manual/en/function.hash.php), maybe you're lucky. ;)
Comment: Both links to level3 fail, I assume you need to be logged in to see that content.
Comment: The links you've inserted are broken/incorrect/whatever. I just get to page stating "An unexpected error has occurred.".
Comment: If they use SHA-1, it's definitely not going to work with MD5.  They aren't interchangeable.
Comment: sorry did not notice that the links were not functional! i re-hosted the specific pages.
Answer: Their example is incorrect. The digest they give is for the file /support/lvlt300kbps.flv and can easily be generated with md5 for that filename, using the lowercase secret as the shared secret. You can see it's identical to the digest given in the FLV example just above it in their documentation.
Comment: you are right! that means they dont include the streamer in the hash whcih makes sense. will try it out on monday!


How to make this petal shape a mesh?

Question:
I am trying to make the petals in this image I made in illustrator in Blender but making it into a mesh that I can solidify so it looks like a 3d ring of petals that come out. How do I make this shape in Blender by itself?
whenever I import it as a svg just hte flower poath it creaste a hollow design. I am clearly very new to all this would like some help please!
Answer: Fill those petals in illustrator and after you fill that in illustrator application you will be able to fill that

How to make this petal shape a mesh?


the range of interleukin 2 and 12 that can be used to activate nk-92 cells

Question: I am one of the biotech students. I want to know the dynamic ranges of interleukin 2 and 12 that i can use to activate the NK-92 Cells.
    thank you
Answer: If you have the resources you should ideally titrate your cytokines. You'll find that cytokines from different vendors may exhibit varying stability or availability in vitro, but also that you obtain varying levels of activation. Standard NK-92 culture conditions are 100-300 IU/mL IL-2 in RPMI1640 medium, 10% serum and 2mM L-glutamine (or 1X GlutaMAX, life technologies). Activation levels depend on how much you want to activate them. Interleukin-12 I'm fairly certain is standard at 10 ng/mL, but should also be titrated.
There's actually a relevant paper with a fair titration looking at granzyme expression at different concentrations of IL2, IL12 and IL15, and different timepoints. They note that NK92 cells show response at 100, 500 and 1000 IU/mL IL2, and at 10-30ng IL12.


Hydrodynamics, non-equilibrium thermodynamics and equations of states

Question: Why is it that in non-equilibrium hydrodynamic modelling, e.g. when the solution is time dependent, people use equations of state that are derived from equilibrium considerations (i.e. the ideal gas law, or an ideal fermi gas EoS etc.)?
Comment: In some cases, it'd have to do with timescales (e.g., the timescale for non-equilibrium processes to being energetically dominant being smaller/longer than hydrodynamics timescales). Not sure that that works for all cases.
Comment: Hi. Edited my question so that it reflects that Im dealing with time dependent solutions.
Comment: My statement was assuming time dependence.
Answer: I think that the key requirement is that the material be in local thermodynamic equilibrium. Even if it is a dynamic situation with mass flow or shock waves running through the material under consideration, if the material is in local thermodynamic equilibrium at every instant in time, then equilibrium thermodynamic concepts such as temperature, pressure, and equations of state are valid and can be applied to describe any local element of the material.
So your question basically reduces to the question of whether there is enough time for the material to reach local thermodynamic equilibrium in any given hydrodynamic situation. I'll give an example based on my own research of compressing and metallizing fluid hydrogen with a strong shock wave (P=0.9 to 1.8 Mbar). The vibrational period of a hydrogen molecule is about $10^{-14}$ second. So within the 5 nsec measurement resolution of our equipment, each hydrogen molecule undergoes about 500,000 collisions and vibrations with neighboring hydrogen molecules. That's plenty of collisions to thoroughly distribute the vibrational and thermal energies among the hydrogen molecules and ensure local thermal equilibrium. As a result, it was valid for us to use hydrodynamic modeling and a hydrogen equation of state to simulate our experiment.
For the particular case of your hydrodynamic modeling setup, you will have to determine if the various internal degrees of freedom in your material (e.g., vibrational, electronic) have time to equilibrate with each other within the characteristic time scale for motion for the material in your setup.
Comment: How should one be sure that the system has reached a state of local equilibrium? are there any quantitative criteria related to this notion?
Answer: You seem to only have a blurry idea of the hydrodynamic approach, so I will add a tad more about the whole idea, mainly to give you a better intuition. Hopefully this will be a useful addition to Samuel Weir's wonderful answer.
A hydrodynamic state is described by the variables: mass density field, energy density field and momentum density field. These are obtained from the microscopic description by averaging over suitable ranges. More importantly this means that such hydrodynamic variables will still satisfy continuity equations. (similar to microscopic quantities)
In order to obtain a weakly coarse grained density $\rho_h$, the microscopic density is averaged over a small volume $v_0:$
$$
\rho_h(\mathbf{r},t)=\frac{1}{v_0}\int_{v_0}\rho(\mathbf{r'}-\mathbf{r},t)d\mathbf{r'}
$$
$v_0$ is chosen to be large enough such that fluctuations of particle numbers are negligible within this domain. Now what is large enough, simply depends on the details of the system considered.
To study the dominant fluctuations, we can e.g. look at the density-density correlation $N^{-1} \langle \hat{\rho_h}(\mathbf{k}), \hat{\rho_h}(-\mathbf{k})\rangle$ of different fourier modes given by ($\mathbf{k}$ is taken here as conjugate to $\mathbf{r}$):
$$
\hat{\rho}_h(t)=\int \rho_h e^{-i\mathbf{r} \cdot \mathbf{k}}d\mathbf{r}
$$
The averaging in the density-density correlations is no longer to be taken as an ensemble average, being at the macroscopic scale, $\langle,\rangle$ is an average over initial conditions where it is assumed that all subvolumes are in equilibrium. In other words, although the system evolves, it only does so on long time and large length (small $\mathbf{k}$) scales, such that all the subvolumes $v_0$ stay in thermal equilibrium. Thus to conclude, all hydrodynamic approaches are taken to work on time scales that are longer than the time needed for local thermalization to take place.


Centre of gravity of a glass

Question: our physics teacher showed us an experiment, she took two plastic glasses but one had a little plastic pong and the other was empty. she filled both with water and kept them on a plane surface. then she slowly tipped them and I thought the first to topple would be the one glass that is empty because the other glass has more weight downwards (because of the pong) so hasn't its centre of gravity fallen? I was wrong ofcourse the first one to fall was the one with the pong.I tried to ask her evn but she explained it in a very vague manner. I dont understand it now it even makes the double decker thing ambiguous  according to this then the double decker has more weight on the bottom so it should also topple over, hope you're getting what im trying to say
Answer: You should refer to the center of mass (CM).
$$x_{CM}=\frac{\sum (m\cdot x)}{\sum m}$$
Since there's ping pong on the surface of the water, the CM of the whole system (water, glass and ping pong) goes up but not down. (notice that the CM of water is below the CM of the ball)
For example, set your original point at the bottom of the glass. Then let's say the CM of you glass and water is $10\text{cm}$ (above the bottom of glass) and the CM of pong is $20\text{cm}$ and the mass of glass and water is $100\text{g}$ and the mass of pong is $5\text{g}$.
Then the CM of whole system is $\frac{10 \cdot 100 + 20 \cdot 5}{100 + 5} = 10.48 \text{cm} > 10 \text{cm}$
Comment: but the ball was at the bottom so didnt the weight at the bottom increase therefore shouldn't the cg be lowered?

Centre of gravity of a glass


How to make video with image Sequence?

Question: When I do render animation with image Sequence , it doesn't work with the message 'Border rendering is not supported by image Sequencer' I think that's why I chose Resolution X:1500 Y:399 instead of 1080p?
but I need a this proportion for some reason. so I want to keep this Resolution's proportion and make video with those images. How can I do that?
Comment: these answer might be related to your issue..
https://blender.stackexchange.com/questions/144754/border-rendering-suddenly-not-supported-by-sequencer-odd-problem-with-renderin
Comment: now I uncheck render region, but there is problem height not divisible by 2
Comment: can't 400 instead of 399 do it for you?
sorry if it's a dumb answer...I don't know much about resolutions.
Comment: I could solve this problem with your answers, Thank you so much
Answer: The problem is that your Render Resolution Y = 399. You didn't mention your render settings but I assume that your output format is: FFMPEG Video with an H.264 codec. The way this encoder works is by dividing your image into macroblocks of a fixed size (e.g. 4x4) and compress these blocks in parallel. Therefore your width and height must be divisible by 2.
If you should change your Height to 400, I think the problem will be fixed.
If you need this 1500 x 399 resolution, you can render it out as a PNG sequence. Then, you can use FFMPEG to create a movie (e.g. MP4) of it. There are plenty of solutions on the internet to do this; see for example https://stackoverflow.com/questions/60788967/ffmpeg-width-not-divisible-by-2-375x500-error.
You will find a more elaborate answer for this common question on https://vse-docs.readthedocs.io/extra-tools/ffmpeg/ffmpeg.html
Comment: I could solve this problem with your answers, Thank you so much

How to make video with image Sequence?


VMWare Player vs VMWare Workstation

Question: Can anyone give me a simple comparison of those two? It is hard to get the idea from their web site.
Comment: Unless you need snapshots, Player does what most need - create VMs, run VMs created via Workstation or ESX/etc.  Just doesn't give you the tabbed layout, but you can run multiple VMs
Answer: VM Player runs a virtual instance, but can't create the vm. [Edit: Now it can.] Workstation allows for the creation and administration of virtual machines. If you have a second machine, you can create the vm on one and run it with the player the other machine. I bought Workstation and I use it setup testing vms that the player runs. Hope this explains it for you.
Edit: According to the FAQ:

VMware Workstation is much more advanced and comes with powerful features including snapshots, cloning, remote connections to vSphere, sharing VMs, advanced Virtual Machines settings and much more. Workstation is designed to be used by technical professionals such as developers, quality assurance engineers, systems engineers, IT administrators, technical support representatives, trainers, etc.
Comment: VMware Player *can* create VMs, as of version 3.
Comment: I'm sure this was accurate when it was created, but it should no longer be the accepted answer. (Unfortunately it looks like OP is no longer active on SO.)
Comment: https://www.vmware.com/products/workstation-player.html
Answer: VMWare Player can be seen as a free, closed-source competitor to Virtualbox.
Initially VMWare Player (up to version 2.5) was intended to operate on fixed virtual operating systems (e.g. play back pre-created virtual disks).
Many advanced features such as vsphere are probably not required by most users, and VMWare Player will provide the same core technologies and 3D acceleration as the ESX Workstation solution.
From my experience VMWare Player 5 is faster than Virtualbox 4.2 RC3 and has better SMP performance. Both are great however, each with its own unique advantages. Both are somewhat lacking in 2D rendering performance.
See the official FAQ, and a feature comparison table.
Comment: The feature comparison table link is broken.
Comment: The question isn't asking for comparisons with VirtualBox. It's Player vs Workstation; which are both VMWare products.
Comment: Now feature comparison table link is working.
Answer: from http://www.vmware.com/products/player/faqs.html:

How does VMware Player compare to VMware Workstation? VMware Player
  enables you to quickly and easily create and run virtual machines.
  However, VMware Player lacks many powerful features, remote
  connections to vSphere, drag and drop upload to vSphere, multiple
  Snapshots and Clones, and much more.

Not being able to revert snapshots it's a big no for me.
Answer: One main reason we went with Workstation over Player at my job is because we need to run VMs that use a physical disk as their hard drive instead of a virtual disk.  Workstation supports using physical disks while Player does not.
Answer: Workstation has some features that Player lacks, such as teams (groups of VMs connected by private LAN segments) and multi-level snapshot trees.  It's aimed at power users and developers; they even have some hooks for using a debugger on the host to debug code in the VM (including kernel-level stuff).  The core technology is the same, though.
Answer: re: VMware Workstation support for physical disks vs virtual disks.
I run Player with the VM Disk files on their own dedicated fast hard drive, independent from the OS hard drive.
This allows both the OS and Player to simultaneously independently read/write to their own drives, the performance difference is noticeable, and a second WD Black or Raptor or SSD is cheap.
Placing the VM disk file on a second drive also works with Microsoft Virtual PC.

VMWare Player vs VMWare Workstation


Would google consider this a "link scheme"?

Question: I work for a County Government.  In an effort to improve our search engine rankings I was considering contacting some of the other Counties in my state and seeing if we could setup an arrangement where we link to them and they link to us.  It seems like a reasonable thing to have a "Other Counties" page with various links on a County website, but it also seems like it's bordering on a link scheme according to Google.
When I read Google's article about link schemes it seems like we hit some of the right reasons for having links on another County's site but also some of the wrong.  Does anyone have any insight into whether this is a good or bad idea?
Answer: It's only a link scheme if the purpose of it is solely to manipulate the rankings. Although your goal is to improve SEO of your site it does make business sense to cross-link amongst counties since they can help them find related information. Cross-linking unrelated sites or with sites known to be link farms is when you start to get yourself in trouble.
Reciprocal links are very common, especially amongst related sites, but they don't really have that much SEO value since they are essentially trading votes so I wouldn't expect this to have any kind of impact on your rankings.
Comment: Very interesting.  So I'd probably only see a benefit if I could convince them to link to us without linking to them?
Comment: That's ideal from an SEO point of view. But the reciprocal links, while not as strong as a one way link, can still benefit you directly as well as indirectly if someone finds you via those links and links to you directly as a local resource, etc.
Comment: Awesome, thanks.  Any chance you have a link I could show my boss regarding the `It's only a link scheme if the purpose of it is solely to manipulate the rankings` part?
Comment: You won't find anything that specific from Google as they rarely spell things out for us like that. Basically if you follow Google's blogs, etc, they more or less focus on *intent* versus *technique* as being the criteria for determining what is acceptable and what isn't.