How do I place top slabs using the /fill command?

Question: I need to place hundreds of blocks and I do that easily with the fill command. But, I can't seem to fill an area with top slabs. I tried /fill x1 y1 z1 x2 y2 z2 minecraft:stone_slab then I get bottom slabs placed.
Answer: In the 1.13 snapshot, use /fill x1 y1 z1 x2 y2 z2 minecraft:oak_slab[type=top].
Answer: The problem here is that the command
/fill x1 y1 z1 x2 y2 z2 minecraft:stone_slab automatically means /fill x1 y1 z1 x2 y2 z2 minecraft:stone_slab 0, the 0 is added. If you change this 0 to another value, the slab will change it's position; 8 is for the upper stone slabs:
/fill x1 y1 z1 x2 y2 z2 minecraft:stone_slab 8

Note: This technique works only for Minecraft versions 1.12.2 and older. For newer versions, check out the other answer on this question.
Comment: @NabeelParkar If this answer solved your problem, hit the check mark. It rewards the answerer, and tells future visitors what solved your problem :)
Answer: Yes, the way that you would do this is by using a square bracket at the end of your block type. If you want top slabs, it would be executed as /fill x1 y1 z1 x2 y2 z2 minecraft:stone_slab[type=top]. If you want to find out some more things about /fill, this video will hopefully help:
Answer: As for top slabs, you can pretty much just tab the thing ingame. I did, and it worked out:
/fill {coördinates} {coördinates} minecraft:stone_slab[type=top]
I just tabbed in the command itself, but now you know it.
Answer: None of the answers posted here work for me (Minecraft Bedrock 1.16+).  I was searching forever to get this to work for me.  I finally figured it out, and is kind of tricky.  The various "original" stone slabs(stonebrick, andesite, cobble, etc.) are broken down into 4 groups(stone_slab, stone_slab2, etc.).  There is an additional data value you need to get more specific(top, double)
This will give you mossy stone brick bottom slabs

/fill x1 y1 z1 x2 y2 z2 stone_slab4

Whereas this will give you regular stone top slabs

/fill x1 y1 z1 x2 y2 z2 stone_slab4 10

Use the various information in the slab article wiki to help build your command.  Took me a lot of tries to get the regular stone upper slabs.  The "Double Upper" used in the article is kind of a bad label as it seems to refer to the single upper slabs instead of 2 slabs together.
Comment: As much as I appreciate you taking your time to figure your problem out yourself, the answers here aren't incorrect. since the question is tagged `minecraft-java-edition`. If you want, you can "ask" a new question regarding the same issue but for bedrock edition and answer it yourself to help others with your issue.
Comment: For my part, I am glad you posted this, because this page is the first search result for "bedrock fill bottom slab". It is what I was looking for, so I upvoted your answer. With the efforts underway to merge Bedrock and Java features, your answer should also apply to Java (but I have no idea if it does). And @Quijibo nobody said the answers here are incorrect. They just don't work for Bedrock. And that matters a lot, because Bedrock has the larger installed base.
Answer: I'm just going to be really straightforward, /fill x y z x y z slab ["top_slot_bit" : true ] NOTE: I do not know if this works for java edition, nor do I know if this works for lower versions (1.19 and below) This only for sure works on 1.20 bedrock edition
Comment: Please read the tags of the question and don't post answers for other editions.


Built navigation menu from Taxonomy with cache

Question: I want to build menu in the navigation Quick launch from Term store. Since the Taxonomy is very huge I want to find a way to store it in the browser's cache using JSOM. Can anyone help me?
Answer: I use JStorage library for this. It uses HTML5 local storage or user data for storing data on the browser.
var data = $.jStorage.get("TermSetCache");

if(!data)
{
    // Populate data from term store using JSOM
    data = GetStuffFromTermStore();
    $.jStorage.set("TermSetCache", data, { TTL: 3600 }); // Cache for 1 hour
}

// Proceed using data
alert(data);

Answer: I used localStorage  function to achieve this goal.
now what I have actually done here to provide the solution. When user first time logs in it will fetch the details and build menu from Taxonomy using the regular script which is taking time. Once it added I am storing HTML Object in the localStorage function. And I am resetting  the localStorage at midnight every day.
Here is code sample to achieve this goal.
if(localStorage.getItem('MenuItem') ===null || localStorage.getItem('LastSaved') != (new Date()).getDate() )// Clears cache on date change.

// Inserting dumy values on cache
localStorage.setItem('MenuItem', '

');

// if No Cached Data;
    if(localStorage.MenuItem.length <100){
    // Your function to build menu from taxonomy.
.
.
.

localStorage.setItem('LastSaved', (new Date()).getDate());
}
//Cached Menu
Else
{
        var MenuItems = localStorage.MenuItem;
        ApplyToMenu(MenuItems); // function to inject the menu items in Quick Lanuch

}

Answer: Take note that if you only use the html5 localStorage API, this cache is built for every individual user separately. Ideally you build a webservice that does the caching for all users together and from within your page, you pull the information from this webservice. Then you can copy the retrieved data into localStorage.
Comment: Thanks Carl, providing additional information. This will help me in future requirement. However my requirement here was to fetch the schema of Terms sets and save it cache (so that I won't need to fire query everytime when page loads) and then associate it with pages (actually filtered pages from a repository called Pages Library) which are relevant to the current logged in user's preferences.


What happens when a token is minted on multiple chains?

Question: Let's say we have total supply of a token set at 10,000,000. There are 9,999,999 tokens at the moment. What if at the same time a token is minted on both Polygon and Ethereum?
Answer: I am in a project that originated on BSC and then expanded to Polygon.  The project tokens can only be minted on the original BSC chain.  The only way they exist on the Polygon chain is via a BSC - Polygon bridge, hence, the total supply is intact.
However, it's also possible that the project can decide to mint tokens on both chains, thereby increasing the original total supply of the Project (usually they would give the Polygon token the prefix p). It's at the discretion of the project.


How do I solve this Black and White Square Box puzzle? It features 3 rows and 3 columns and in each square has 2 columns with three squares per column

Question:
My buddy and I have been trying to figured out how to solve this puzzle sent to us by a professor several weeks back. All we've been asked to answer is, "What do you think is the correct answer and why?". For some context, our professor is a mathematician who creates puzzles as exercise projects for our class to solve every semester. Each puzzle is different but are meant to apply the same abstract learning/pattern identification techniques to aid our learning.
Comment: With six boxes arranged in that exact pattern, probably a good idea to try Braille first.
Comment: Does your professor normally present you with puzzles of this sort, or do the puzzles usually have a question mark somewhere? As given, there doesn't appear to be a question asked (apart from the 'what is the answer?' question).
Comment: @IanMacDonald Not necessarily...there have been times where he asks if we've generally identified a pattern or will specifically ask for our methodology/thought process for determining our outcome.
Answer: The pattern here is that

 in each row, the white square is moving clockwise one step at a time; in each column, the red slash moves clockwise one step at a time.

If there's some additional "answer" they're looking for, I'm not sure what it could be.
Answer: It's a bit of a leap in logic, although another potential answer if that if you treat each white square and red lined square such that...

 ...each represents a separate number. You can get to these tables fairly easily:

 Subsequently, if you divide the content of table A by the contents of table B you get the following sequence where the sequence of totals of each row and column match:

Comment: Interesting idea, but you have a typo in your red line table. Bottom centre should be 3.
Answer: A possible pattern is

 That the red slashes occupy each cell in the inner left column twice each and the inner right column once each.

 The white squares occupy the top right, middle left, and bottom right cells twice each, and the others once.

 Overall this leaves the middle right cell as the only cell that is never occupied by the same thing twice. Furthermore outer top middle square is the only one where the red slash and white box occupy the same cell and it's the middle right cell.
Answer:
There are 9 black regions in the puzzle. I numbered them from 1 to 9 as shown above.
Each black region has 3X2 white bordered cells in them. One of the cell is having red slant line and another cell is filled with white color inside with some padding.
Now on quick wink, we can see that the entries in the cells changes their position from one region to another.
The "Red Line" moves clock wise in a cycle of  4steps - 3steps - 3steps (inclusive of current cell)
The "White filled" cell  moves clock wise in a cycle of  2steps - 2steps - 3steps ( Inclusive of current cell)
Journey of "Red Line Cell"
At first it was in the 2nd row - 1st column cell in the black region numbered as 1.
It took 4 Steps clockwise and landed in 2nd row - 2nd column in Second black region.
and then it moved 3 steps clockwise and landed in 3rd row - 1st column cell in 3rd black region.
From there it took 3 steps clockwise and landed in 1st row - 1st column cell in 4th numbered black region.
Thus it takes 4 steps - 3 steps - 3 steps
Journey of "White Filled Cell"
At first it was in 1st row - 2nd column cell in the black region numbered as 1. Then it started journey with 2 steps clockwise(inclusive of current cell) and landed in 2nd row - 2nd column cell in 2nd black region.
After that as per cycle, it took 2 steps clockwise (inclusive of current cell) and landed in 3rd row - 2nd column cell in the 3rd numbered black region.
As the next step in the cycle, then it took 3 steps clockwise(inclusive of current cell), it landed in 2nd row - 1st column cell in the 4rd numbered black region.
If we apply the same cycle repeatedly, remaining cells will be revealed.
Answer: Top centre square is the correct answer. If we consider, each square as a 6*2 matrix the red slash and white shade lands on the following matrix indices.
Red slash
<code>                    (2,1)(2,2)(3,1)
                    (1,1)(3,2)(2,1)
                    (1,2)(3,1)(1,1)
</code>
Index not visited twice - (2,2)(3,2)(1,2)
White shade
<code>                    (1,2)(2,2)(3,2)
                    (2,1)(1,1)(1,2)
                    (3,2)(3,1)(2,1)
</code>
Index not visited twice - (2,2)(1,1)(3,1)
Index not visited twice that is common between red slash and white shade : (2,2)


How do I snap a photo on my iPhone with the apple earphones

Question: I have an iPhone 6s and am running iOS 10. I just tried to take a photo using the earphones volume up and down but nothing triggered. I also tried another pair of earphone, but it still didn't work. Is there a setting I'm missing? or did they disable this in iOS 10.
Answer: I successfully took a photo via the following process with iPhone 7 & iOS 10 & the apple earbuds (with lightning connector, and also with lightning to 3.5mm jack variant of Earbuds):
Open the default iPhone camera app and, with earbuds connected, press volume down on the in-line remote.
However, the above process did not work when the apple earbuds were replaced by a set of Anker bluetooth earbuds, paired and connected to the phone.


How do I close an open port from the terminal on the Mac?

Question: I opened port #5955 from a java class to comunicate from a client. How do i close this port after I am done? and also which command can show me if port open or closed?
Comment: How did you open that port? It is not clear whether you are talking about opening and closing the ports in the java application or from the firewall.
Answer:
Find out the process ID (PID) which is occupying the port number (e.g., 5955) you would like to free
sudo lsof -i :5955

Kill the process which is currently using the port using its PID
sudo kill -9 PID

Comment: Sending -9 should not be the first attempt to kill a process, and it a very bad habit. As I recall, you should first just use `kill PID`(which implies -15), then try -2 and -1. -9 is the last resort only if **every** other options failed to work.
Comment: did kill pID without any flags as suggested by @Meow and this worked for me
Comment: this answer works for me, but what does those numbers (15,2,1,9) mean?? thanks in advance.
Answer: To find the process try:
sudo lsof -i :portNumber

Kill the process which is currently using the port using its PID
kill PID

and then check to see if the port closed. If not, try:
kill -9 PID

I would only do the following if the previous didnt work
sudo kill -9 PID

Just to be safe. Again depending on how you opened the port, this may not matter.
Answer: EDIT
In 09/2022 this helped me for MacOS Monterey M1 Pro Chip:
sudo lsof -t -i tcp:yourPortNumber | sudo xargs kill
In 2018 here is what worked for me using MacOS HighSierra:
sudo lsof -nPi :yourPortNumber
then:
sudo kill -9 yourPIDnumber
Comment: `lsof -nPi` is slightly better because the port number is actually visible in the output and you get a better feeling of what you are killing.
Comment: Also helpful just to see all listening ports' info: `sudo lsof -nPi | grep LISTEN`
Answer: very simple find port 5900:
sudo lsof -i :5900

then considering 59553 as PID
sudo kill 59553

Comment: This doesn't add anything to the existing answers!
Comment: clear and concise solution.
Answer: One liner is best
kill -9 $(lsof -i:PORT -t) 2> /dev/null

Example :
On mac, wanted to clear port 9604. Following command worked like a charm
 kill -9 $(lsof -i:9604 -t) 2> /dev/null

Answer: However you opened the port, you close it in the same way. For example, if you created a socket, bound it to port 0.0.0.0:5955, and called listen, close that same socket.
You can also just kill the process that has the port open.
If you want to find out what process has a port open, try this:
lsof -i :5955

If you want to know whether a port is open, you can do the same lsof command (if any process has it open, it's open; otherwise, it's not), or you can just try to connect to it, e.g.:
nc localhost 5955

If it returns immediately with no output, the port isn't open.
It may be worth mentioning that, technically speaking, it's not a port that's open, but a host:port combination. For example, if you're plugged into a LAN as 10.0.1.2, you could bind a socket to 127.0.0.1:5955, or 10.0.1.2:5955, without either one affecting the other, or you could bind to 0.0.0.0:5955 to handle both at once. You can see all of your computer's IPv4 and IPv6 addresses with the ifconfig command.
Answer: You can also use this first command to kill a process that owns a particular port:
sudo netstat -ap | grep :<port_number>

For example, say this process holds port 8000 TCP, then running the command:
sudo netstat -ap | grep :8000

will output the line corresponding to the process holding port 8000, for example:
tcp  0  0 *:8000   *:* LISTEN  4683/procHoldingPort

In this case, procHoldingPort is the name of the process that opened the port, 4683 is its pid, and 8000 (note that it is TCP) is the port number it holds (which you wish to close).
Then kill the process, following the above example:
kill  4683

As others mentioned here out, if that doesn't work (you can try using kill with -9 as an argument):
kill -9 4683

Again, in general, it's better to avoid sending SIGKILL (-9) if you can.
Answer: Find the process ID using command
lsof -n -i4TCP:8080

After getting the processId
sudo kill -9 processID

Then provide your system password.
Answer: I use lsof combined with kill, as mentioned above; but wrote a quick little bash script to automate this process.
With this script, you can simply type killport 3000 from anywhere, and it will kill all processes running on port 3000.
https://github.com/xtrasimplicity/killport
Comment: You saved my day. For some reason `lsof` in combination with `kill` didn't  return anything and made my script hang on macOS Sierra. But `killport` works like a charm and is faster. Thanks!
Answer: I have created a function for this purpose.
function free_port() {
    if [ -z $1 ]
    then
        echo no Port given
    else
        PORT=$1;
        PID=$(sudo lsof -i :$PORT) # store the PID, that is using this port

        if [ -z $PID ]
        then
            echo port: $PORT is already free.
        else
            sudo kill -9 $PID # kill the process, which frees the port
            echo port: $PORT is now free.
        fi
    fi
}

free_port 80 # you need to change this port number

Copy & pasting this block of code in your terminal should free your desired port. Just remember to change the port number in last line.
Answer: Simple One-liner
There is a way more straightforward command today, than the other ones (without Sudo, packages or multiple lines)
To kill port 8080 simply call:
lsof -ti tcp:8080 | xargs kill
Answer: This seem to work for me. Just change your_port_number into the port number you want to stop.
sudo lsof -t -i tcp:your_port_number | xargs kill -9

Answer: try below, assuming running port is 8000:
free-port() { kill "$(lsof -t -i :8000)"; }

I found the reference here
Answer: When the program that opened the port exits, the port will be closed automatically. If you kill the Java process running this server, that should do it.
Answer: For Linux/macOS:
Step 1:
sudo lsof -i :5955

Step 2:
Note the PID (Process ID) value that appears in the printout.
Step 3:
kill <PID>

Answer: This script to Stop port will help you to stop the port by writing stop <portnumber> to kill the running port in the terminal. it is usually handy when I try to start a program and the port is already occupied. It uses the below code.
pid=$(lsof -ti tcp:$1)
if [[ $pid ]]; then
  kill -9 $pid
  echo "Congrats!! $1 is stopped."
else
   echo "Sorry nothing running on above port"
fi

https://www.hectane.com/blog/stop-port-in-terminal
Answer:
First find out the Procees id (pid) which has occupied the required port.(e.g 5434)
ps aux | grep 5434

2.kill that process
   kill -9 <pid>

Comment: Use following command to find port        `sudo lsof -i :5955`


Screening factors - why can we use them?

Question: The energy of an X-ray transition from the level $n$ to the level $m$ can be written in the form:
$$ \newcommand{\p}[2]{\frac{\partial #1}{\partial #2}} \newcommand{\f}[2]{\frac{ #1}{ #2}} \newcommand{\l}[0]{\left(} \newcommand{\r}[0]{\right)} \newcommand{\mean}[1]{\langle #1 \rangle}\newcommand{\e}[0]{\varepsilon} \newcommand{\ket}[1]{\left|#1\right>}
\Delta E=R_\infty \l \f{(Z-\sigma_n)^2}{n^2}-\f{(Z-\sigma_m)^2}{m^2}\r$$
I know that here $\sigma_n$ and $\sigma_m$ represent 'screening factors' (roughly independent of $Z$) and take account of the screening of nuclear charge by other electrons, but I am yet to find an explanation of why this form can be and is chosen with screening factors independent of $Z$. And in what cases the screening factors can be used. Please can someone explain.
Answer: The expression is semi-empirical, and intended to reproduce the famous Balmer formula for the lines of hydrogen:
$$
\Delta E\sim R_\infty\left(\frac{1}{n^2}-\frac{1}{m^2}\right)\, .
$$
The Balmer formula can be obtained using solutions to the Schrödinger equation for the hydrogen atom and generally for single-electron atoms with $Z$ protons, where energy levels
$$
E_n\sim R_\infty \frac{Z^2}{n^2}\, .
$$
Phenomenologically, electrons in the outer shells do not see the full nuclear charge $Z$, but net charge smaller than $Z$  since the inner electrons "screen" or partially cancel the charge of the nucleus, creating a smaller net electric potential (still assumed to be central in nature if the screening is from electrons in closed atomic shells).  This is the origin of the $Z-\sigma_n$ factor.
Since the $\sigma_n$ depends mostly on inner electrons (provided their orbitals are more or less completely inside the outer electron orbitals), this quantity does not depend very much on $Z$.


DVD Playback using Xubuntu

Question: I have updated my software and installed VLC and installed the DVD Extras pack as suggested but the DVD will not play. I have tried several DVD's and reinstalled the Xubuntu from fresh and updated and upgraded but still no play I get the error message: GStreamer backend error: No valid frames found before end of stream. I have installed the codecs that came with the Extras pack and confirmed the license agreement. What have I missed....
Answer: I searched for solutions to these error messages and found the answer here,  that solved my issue with DVD's not playing The page has some useful tips and tricks to solve many problems with your OS. I was instructed to open the terminal and cut and paste this text, sudo apt-get install libdvdread4, followed by, sudo /usr/share/doc/libdvdread4/install-css.sh, this has fixed the errors and now the DVD's play as the software installed decryption information to allow this.

DVD Playback using Xubuntu


Magento 2 Disabling Redis Session Locking

Question: We're seeing some performance gains if we disable session locking in Redis. We haven't found any issues with doing this in our testing, but wanted to see if anyone has tried that and if they have run into any issues or if anyone would advise against doing this for any reason.
Answer: We have disabled sessions on our live site and haven't run into any issues.
We reenabled session locking because it caused a rare issue with PayPal checkouts. We ended up writing a module to disable session locking for specific urls for the custom section of our site where it was a bottleneck and not necessary.
Comment: Could you share this module in Github?
Comment: How you solve it? i have double amount issue with paypal
Answer: We recently saw issues where customers could not add to cart. The setting had been enabled for many months, but starting showing this behavior only two days ago. There must have been another contributing factor. I have high confidence that this was the issue though.
On add to cart, the page would show no change and no errors. The cart would never have items added.
The issue was that a new quote was being generated after adding to the cart because a new session was started. The behavior was not consistent, but very repeatable in testing.
Enabling session locking fixed this behavior entirely. We are enabling the setting again across projects and looking into other fixes to the performance issues caused by Redis locks.


Why do characters with wet hands need to explain that they just washed them?

Question: The latest instance I can think of would be Spider-Ham from Spider-Man: Into the Spiderverse - YouTube link of clip. A character will say something along the lines of "I just washed my hands, that's why they're wet", as if there's a default, frowned-upon reason they might be wet that everyone will otherwise assume. Is there any?
Comment: On the 'gross scale' shaking hands with somebody with damp hands may only be a 3, but it's still gross. Sweaty handshakes are revolting. Explaining why this handshake is going to be damp is a 'please don't think I'm gross' precursor.
Comment: Welcome to the site - sorry your first question has not gone down well.  I think that is because its really not movie specific, and is just a question about social norms.
Comment: I am voting to close because this question lacks decorum.  While that might not be a strict guideline of this Exchange, I feel we owe it to each other to keep to a minimum of civility in our communication.
Comment: @iandotkelly I looked at the whole list of SEs and there wasn't a social norms one, this was the closest thing I could link it to :/
Answer: It would be useful to have more examples. You asked the question about this sort of thing in general, so this answer isn't specific to Into the Spiderverse.  I don't remember that scene to be honest.
Dialog generally needs to fill a purpose.  It is hard to see why a screenwriter would put that in when it would be better for the whole issue simply not to come up.  It's not real, the characters hands can be dry or the other character can not notice by fiat of the writer.
There's a couple of reasons why it might make sense to include such a bit of dialog.
To indicate the second character is the sort of person who reacts badly to a damp handshake and/or the first character is the sort of person who feels the need to make an excuse.  Perhaps the first character really wants to make a good impression.
To indicate the first character is either generally, or for specific reasons, sweaty and they are making up a lie to cover for this.
To indicate the two characters are awkward with each other for whatever reason.  This dialog is typical of the sort of thing people might say to fill in an awkward silence.
Answer: Maybe they wiped their nose, maybe they picked their nose, maybe they shook their peter a little too hard after going to the loo, maybe they had just rubbed lotion on their skin so they wouldn't get the hose again...  Who knows.  But sometimes it's better to put someone's mind at ease before they wonder which of the above are true.
Comment: 1+ For finding a way to include Buffulo Bill! XD


Roof Ridge Venting - When in 2012 did roof venting become required instead of standard roofing codes?

Question: In what month of 2012 did roof ridge vents become code, as opposed to standard roofing when roof ridge venting was not a requirement? I ask because I need to present as evidence to the BBB (Better Business Bureau).
Comment: In what state do you reside?
Comment: Code changes almost always begin on January  1  are you asking about international residential code? Some state code? Or the NRCA codes. (National roofing contractors association)? Or some random local county or municipal code?
Comment: Who is your AHJ, and what Code are you discussing here?
Answer: Each state "adopts" the new Building Code after it has been reviewed, changes made, and approved by the State Building Codes Office. Adoption occurs on October 1, (start of the new fiscal year/budget,) with amendments adopted throughout the year.
Little known fact is that the Code is divided into two parts: 1) construction, additions, etc., and 2) maintenance.
You don't need a Permit for "maintenance", (I.e.: painting, carpet replacement, etc.) Re-roofing is often placed in the "maintenance" category. Each jurisdiction makes their own determination regarding re-roofing.
However, roofing (initial installation) is usually in the construction category and needs a permit.


Is a string taut if the tension is zero?

Question: I'm studying vertical circles and a particle on a string will remain in motion as long as the string is taut. However, what if there is 0 tension in the string? Is it still technically taut?
Comment: What are "vertical circles"? Could you please clarify the motion you are considering. (For example, by supplying a sketch of the considered system).
Comment: The tension in a vertical string (http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/cirvert.html) depends on the part of the string in question. The link above says the tension at the top is equal to the tension at the bottom plus $6mg$.
Answer: The tension being zero is right at the moment of transition between the string being taut and the string being slack; usually in "particle on a string" problems you have to find the minimum or maximum of some value, and usually the trick is to take the tension equal to zero as this is where the string is "barely" taut.
Comment: Something to do with inertia?
Comment: What do you mean?
Answer: revised
If the particle is moving just fast enough such that the particle is moving in a circle, the string is fully expanded because the particle is still moving in a circle, even though the string doesn't need to pull on the particle to maintain that circular motion (in this case gravity is usually doing all the pulling necessary). Since the string is fully expanded at this point, in this sense it is still taught. However, most people would relate taught to the feeling of, e.g. a guitar string, where the string resists your pushing into it. In this circular motion case, such a string would still end up feeling like it was resisting your pushing into it, since in order to change the shape of the string you would necessarily have to also move the ball around. So, It would still feel taught.
If the string isn't moving fast enough to maintain circular motion at the top, and instead there is a brief period where the ball is falling, the tension would also be zero here and there would be extra curves in the string, and so you wouldn't have to move the ball in order to move the string around, so in this case it would not feel taught.


What folders can be safely deleted after building UE4 from source?

Question: What folders, if any, can be safely deleted, after building UE4 from source?
After the build, UE4 files occupy 65 GB of disk space, which is way above comfortable for me, since I only had 72 GB free.
I would like to cut the folder down to size, say at least 25 GB.
Are there any files that are not required to use the Unreal Engine with full functionality? Thanks
Answer: You can generate an installed build:
https://docs.unrealengine.com/en-US/Programming/Deployment/UsinganInstalledBuild/index.html
This will output a standalone binary engine that is somehow identical to engine you would download from the launcher .
Then you can delete all the source files.


A word for a new type of exam

Question: In Saudi Arabia, the Ministry of Education has devised a new type of examination for those who flounder or stumble in some school subjects because of illness or family circumstances. My question is: Is there a specific name for such an examination? I have tried to figure out some names such as 'stumbling examination' and 'floundering examination', but I am not really sure if these terms are valid.
Comment: Hello, Mido. Naming requests are off-topic on ELU, but this seems a far more deserving cause than many. **Don't** use 'stumbling examination' or 'floundering examination': they sound ludicrous, and (worse) insulting.  Perhaps someone will check whether 'mitigationary' is listed in OED.
Comment: @Edwin: You're right.
Comment: @Edwin Ashworth "mitigationary" is not (thank God) listed in the [OED](http://www.oed.com/noresults?browseType=sortAlpha&noresults=true&page=1&pageSize=20&q=%27mitigationary&scope=ENTRY&sort=entry&type=dictionarysearch).  When I search for this word, I am asked if I mean  •mitigation or
•mitigatory
Comment: How about a **second chance** exam.
Answer: If a student misses an examination because of illness or family circumstances or because of another examination at the same time, and then takes the same or equivalent examination at a later date, this is commonly called a make-up examination.
For example, see this information from the Rutgers School of Engineering:

Students having an exam conflict should contact the instructor of the
  course(s) involved for information regarding the arrangements for the
  make-up examination.

If a student, on the other hand, has an acknowledged learning disability, then he or she takes the examination at the same time as the other students, but with adapted content or other accommodations such as extra time or a proctor reading the questions. The examinations for such students are commonly called modified assessments or alternate assessments.
For example, see this information from  Centinela Valley Union High School District, which uses the CMA:

The California Modified Assessment (CMA) for Science is an assessment
  for students in grades five, eight, and ten who have an individualized
  education program (IEP) that designates they take the CMA for Science. ... The CMA for Science allows students with disabilities greater access to an assessment that helps measure how well they are achieving California's content standards for science that were adopted by the SBE in 1998.
Comment: l really appreciate your answer. I know the term 'make-up exam', but l wasn't sure whether l could use it here.
Comment: +1  Make-up exam was the term used when I was at MIT (so naturally it is correct :)).
Answer: Remedial Examination seems to fit the definition quite well, and is in common usage.
"Remedial : concerned with the correction of faulty study habits and the raising of a pupil's general competence"
But more generically, something is remedial if it is the remedy to a problem.
Comment: The term 'remedial exam' seems to have a different sense: a re-take for those who've failed the normal exam. I couldn't find any reference to those genuinely struggling through no fault of their own (this is a dissimilarity with the single word 'remedial). At any rate, attributed supporting evidence of any kind is missing here (and ait would need to address the two-word term not just the adjective).
Comment: I appreciate your reply.

A word for a new type of exam


Can we quantify the pitch of a sound that is a mixture of many frequencies?

Question: How is the pitch of a sound defined quantitatively when it is a mixture of many frequencies? For example, the sound emitted by a plucked guitar string, or say, the pitch of somebody's (normal) voice. I know that female voices are generally of higher pitch. But can we quantify the notion of pitch? My guess is that the pitch of a complex sound depends on the relative amplitudes of the different frequency components.
Comment: @rob overtone singing doesn't work by removing overtones, it works by creating a resonance that _amplifies_ certain overtones. Basically, it's not just the perception of multiple pitches, it **is** multiple pitches: two oscillators, though one of them happens to be excited by the other.
Comment: Have you read the article [Perception of musical pitch varies across cultures](https://news.mit.edu/2019/perception-musical-pitch-cultures-0919)?
Comment: Pitch perception is a complicated biosocial phenomenon. For instance, by selectively removing overtones from a harmonic series, you can create the perception of at least two pitches. [This artist is exceptionally good at it](https://youtu.be/UHTF1-IhuC0), but it's a pretty great party trick.
Comment: @leftaroundabout "Removing" vs "amplifying" is a distinction without a difference. The transition from "ooooo" to "eeeee" is managed by amplifying the higher-frequency part of the overtone series. The overtone singer amplifies more selectively than a person producing a more standard vowel. There is only *one* oscillator, the vocal fold, in a human overtone singer; a second oscillator would have its own overtone series, which are missing from the spectrographs in the link. For a two-oscillator system try activating your vocal folds while whistling; the effect is very different.
Comment: @rob I mean, this is to some degree a matter of terminology-lawyering. In fact _every_ audio filter (except digital FIRs) consists of a series of (more or less) damped oscillators that are (more or less) linearly driven by the input signal. As you make the damping weaker (overtone singing vs normal speech), it'll behave more and more like a standalone oscillator that keeps on ringing after the input signal has stopped, and if there are nonlinearities (as with the rapid air stream through the lips when you whistle) it can even self-excitate at a stable amplitude. It's still _all an oscillator_.
Comment: @rob ...what I don't like about your phrasing "removing overtones" is that it suggests the spectrum stays largely as-is except for some partials that are strongly _reduced_ in amplitude. That's an effect that happens all the time with _phase cancellation_ e.g. when you're standing at a particular spot between two speakers. But such changes don't sound like the overtone-singing effect at all, in fact our ears often don't even notice missing partials unless they change over time (https://en.wikipedia.org/wiki/Phaser_(effect)).
Answer: Pitch can be described as a subjective perception of an auditory stimulus which cannot be objectively, unambiguously quantified. It is strongly related to the objective physical property of frequency such that higher frequencies typically correspond to higher perceived pitch, but even notes with identical frequency can be perceived as having different pitches, depending on how loud they are, what other frequencies are played at the same time or in close proximity, and other factors. A pure sine wave is usually fairly easily mapped to its perceived pitch, but more complex sounds may not be.
A mixture of many frequencies may have a dominant frequency which is perceived as the overall pitch of the sound, or the many frequencies may mix in a way that are not perceived as any particular pitch at all. The sound of a snare drum, for example, is not usually perceived as having any particular pitch, but almost everyone would agree that a snare drum has a higher pitch than a bass drum. The bass drum resonates more strongly with lower frequencies than the snare drum does, but neither sound is very well described as having a particular pitch.
You may be interested in auditory illusions like the Shepard–Risset glissando, which is perceived as having ever-ascending pitch, despite the fact that the frequencies remain within a fixed window. We can objectively quantify the underlying frequencies, but it is not always simple to map a waveform to the subjective experience of pitch. As pointed out by @march, it's even possible to perceive a pitch from a complex tone when the corresponding frequency is damped or even completely absent from the waveform. The pitch produced by a timpano, for example, is implied by the harmonics it produces, with the fundamental frequency resonating much more weakly than higher frequencies - the perceived pitch of the drum is not simply the frequency with the highest amplitude. Practical applications of this effect can be seen in the design of some sound systems that have small speakers - by using a particular combination of higher frequenies, it allows the listener to experience low pitches that the speaker is not even physically capable of producing!
Comment: There's also the auditory illusion of the "missing fundamental." This one's interesting because provided that the frequencies making up a sound are all members of a harmonic series, the pitch is often associated with the fundamental frequency of that harmonic series, even if that particular frequency is missing from the Fourier spectrum of the sound.
Comment: More on [Shepard tone (Wikipedia)](https://en.wikipedia.org/wiki/Shepard_tone).
Comment: What @march said. This "missing fundamental" effect occurs with bells & chimes, see https://en.wikipedia.org/wiki/Strike_tone
Comment: The subjective perception of complex tones is, um, complex. ;) There has been a lot of research on this, particularly in regard to speech sounds. See https://en.wikipedia.org/wiki/Formant
Answer: Short Answer:
Use the lowest of your frequencies, also known as the fundamental, to represent the pitch.
Full Answer:
First off, it seems worth noting that many sounds that consist of many frequencies don't have a pitch at all. For example, consider the sound of a piano  chord or the hiss of a radio with bad reception. In cases like these, you do have many frequencies, but you do not have a pitch. There is too much going on with the sound to represent it with a single number.
Now let's move on to sounds where you can identify a pitch, as in the examples you gave. In a plucked guitar string or a human voice, the sound would consist of a fundamental and its harmonics. The frequencies of the harmonics would be integer multiples of the fundamental's. And the amplitudes of the harmonics, relative to the fundamental's, collectively make up the timbre. They are  why the same middle-C sounds different when played by a guitar than when sung by a human.
For sounds like these, the one number describing their pitch is the frequency of the fundamental.  That's the number you're looking for.
A Postscript On "The Missing Fundamental"
In a comment, Michael Seifert pointed out the curious case of the missing fundamental. It is possible to synthesize a sound that contains only the overtones but omits the fundamental.  (The Wikipedia page on the phenomenon also mentions some naturally-occurring sounds where the fundamental is greatly attenuated.)
When that happens, an auditory illusion in the human brain can make a human hear a fundamental even though it is not in the spectrum. Here is a YouTube video showcasing the phenomenon.
When the fundamental is missing, the perceived pitch is often, but not always, the highest common divisor of the overtones. Informally, this is what the fundamental would have been if it wasn't missing.
Comment: Not all pitched sounds consist of a fundamental and its harmonics;  sometimes the [fundamental is missing.](https://en.wikipedia.org/wiki/Missing_fundamental)
Comment: I did not know that, Michael Seifert. Thank you, I'll look into it!
Answer: The technical, quantitative definition of pitch only applies to "single sounds" such as music notes. Here, the pitch is the fundamental frequency.
However, when applied to "multiple sounds" collectively such as a voice or all the notes an instrument is capable of, the meaning is only qualitative. In this context, the more correct term for the quantifying "pitch" would the "range" which is self-explanatory whereas "pitch" refers to a vague qualitative sense of what is dominant in the range.
If you want quantitative metrics more specific than the range then you'll probably need to make one up and just make the metric known.
For example, you could narrow down the aformentioned range down a bit to where more than 50% of the time-averaged power is contained within some standard deviation during "normal sound production" (i.e. no falsetto).
If you're after a single number then perhaps the frequency component that results in the largest time-average power during normal sound production. You may also need to scale it against the sensitivity of the human ear.
Comment: If we want to be *really* pedantic, only an eternal pure sine wave has an exact frequency. ;) Somewhat ironically, it's (usually) easier to identify the pitch of a sound that contains at least a few strong components of the harmonic series, rather than a more pure sine-like tone. Eg, it can be easier to tune a guitar to a note from a harmonica or [pitch pipe](https://en.wikipedia.org/wiki/Pitch_pipe) than from a tuning fork.
Comment: @PM2Ring I'm all for being pedantic. Is it easier to identify with harmonics than a pure sine tone? I've never gotten a chance to try to tune an instrument to a pure tone. I should get a tuning fork
Comment: A tuning fork is fine in a quiet environment, but it's not so great if there are competing sound sources (even if the tuning fork is loud enough). It's a bit like trying to use a laser as a flashlight. :) It's easier to hear when the guitar string is in tune when its harmonic series matches up with the harmonic series of your tuning device. The electronic version of this is that it's easier to tune to a square wave than a sine wave, since the square wave has a nice big fat harmonic series.
Answer: In physics, high pitch is translated to high frequencies and low pitch is lower frequencies in sound frequency spectrum. for example in the spectrum chart below:
the signal has most of its power gathered around 300KHz.
the way to achieve such spectrum for a signal, be it voice signal or not, is to use Fourier transform on the given signal.
for your question, human hearing spectrum is from 20Hz-20KHz.
although speaking spectrum is much lower,
being for females from 165-255Hz and for males 85-155Hz
for seeing music notes pitches frequencies,
see: https://en.wikipedia.org/wiki/Scientific_pitch_notation
this will hopefully give a hint for what you are looking for.
Comment: If the frequency vs intensity plot has several peaks (say, one around 100kHz, one around 200 kHz, one around 300 kHz, 400 kHz etc), what would be the pitch? At least, intuitively?
Comment: @Solidification 100 kHz. Any string, tube (e.g. vocal cords), etc. make some base frequency and then a bunch of harmonics above that which are some multiple of the base frequency. The base frequency is the pitch you hear, and the harmonics help give the instrument its distinct quality.
Comment: @SeñorO Why does the base frequency determine the pitch of the sound? Is it because it carries the most power? In that case, the power spectrum will have a very tall peak concentrated around base frequency compared to the peaks at other harmonics. Is that right?
Comment: @Solidification no, it's because we're used to the exact harmonics. For example, a guitar string with fundamnetal 100 Hz, it'll produce 100, 200, 300, 400, 500, etc. In fact, if your brain hears 200, 300, 400, 500, etc. **without** the base 100Hz, your brain will still perceive it as a 100Hz note and just assume the fundamental is weak, because your brain knows those harmonics can only be produced by a 100Hz fundamental in physical objects.
Comment: Actually i see that @march mentioned this concept above, called "the missing fundamental"
Comment: As many other contributors have mentioned, **pitch** is a psychoacoustical quantity/measure. This implies that it is related to the human hearing mechanism. The point I am trying to make here is that the plot you have provided, most probably, *has no pitch* because it cannot be heard. Pitch shift it downwards by some octaves and it will go into the audible range and it "may" have a pitch...
Comment: @Solidification you have to determine each frequency's intensity, the frequency with the highest intensity is the determining frequency. in real applications, no frequency intensity is absolute zero. hence you are technically hearing all of them that are in your ear's hearing range. this means any pitch has some "impurities". an ideal string on a vocal device (be it human vocal cords is one that negates unwanted frequencies and gives you a pure delta function on the frequency spectrum with only one frequency, which in time domain it will be sine wave.
Answer: Forget about Fourier series for a while. Pitch isn't really about frequencies of sinusoidal components. It's just the frequency of how often the signal's oscillation repeats per time unit. We have a signal $u(t)$, and we're interested in its periodicity, i.e. the constant $\tau$ such that
$$u(t+\tau) = u(t)\quad \forall t.$$ The frequency, or pitch, of $u$ is then simply the reciprocal: $\nu = \tfrac1\tau$.
There are at least three problems with that:

In the real world, no signal is truely periodic. There will always be at least small pertubations: literally noise but also effects like amplitude decay over time or similar. So what we should rather look for is $u(t+\tau) = u(t)+\varepsilon\ \forall t$, for some suitably small $\varepsilon$.
$\tau$ is not unique. In particular, a signal that repeats after time $\tau$ also repeats after time $2\times\tau$ etc. The $\varepsilon$ allowance makes it even worse, since a continuous signal will always change only by a small amount in sufficiently short time.
In reality we also can't have infinitely long signals. Right at the start of a guitar note it isn't periodic at all, rather you have a transient.

But still: for signals like voice or flute or whatever, we actually do have periodicity over a substantial time (on the order of a second) with hundreds of complete oscillations that are to a good approximation the same. So pitch as repeat-frequency is a sensible notion. In practice, to determine $\tau$ one uses the autocorrelation of the signal.
Again, none of this relies on Fourier decomposition, although typical implementations of autocorrelation do use a fast Fourier transform under the hood because that's computionally more efficient than directly carrying out the integration in time-space.
For most e.g. musical instrument signals, the periodicity-frequency happens to equal the lowest strong Fourier partial, aka the fundamental, which in many cases is also the one with the strongest amplitude. But this is by no means universal: in fact it is possible to completely remove the fundamental while changing neither the autocorrelation-periodicity nor the human-perceived pitch. It only changes the timbre of the sound.
Answer: The description of pitch consisting of multiple frequencies that are harmonics of the fundamental frequency is called timbre. It is the timbre of a note that gives the difference in tone between a guitar playing an A at 440 Hz and a trumpet playing an A at 440 Hz. Since harmonics are integer multiples of the fundamental frequency at lower amplitudes, when added to the fundamental, these harmonics change the shape of the waveform without altering the frequency of the fundamental allowing  pitch to be retained. It is possible to quantify harmonic content (number and relative intensity).
In addition to harmonic content, timbre also includes the attack-decay envelope of the note, and vibrato/tremolo. So a full quantification of timbre is difficult.


Does my umbrella plant need to be trained?

Question: I'm not planning to size up the pot for my umbrella plant, I'm happy to keep it at this size and let it fan out. However I'm not sure if the branches will just get longer and less manageable (they're certainly longer than a few months back). Do I need to start training it or winding the branches together if the small pot won't stop the growth?
Answer: No, don't wind them together - the stems support themselves, and you will restrict air flow if you try to tie them together. The likely cause of the lateral shoots getting so much longer, longer than they usually do, is insufficient light - these plants like bright daylight, but not direct sun other than a little early morning or late evening. Over time, this plant will get quite tall (mine is currently 5 feet), but if it gets too large for your liking, you can always cut off about 8 inches of stem from the top, strip off the lower leaves, pop it into a bottle of water and wait about six weeks, when it will produce roots, and you can pot it up and start over. In the meantime, place it somewhere it gets more natural light.


Can Cisco vpn client .pcf file from a PC be used on a Mac?

Question: i recently switched from a PC to a Mac. I want to know if my previous Cisco VPN client .pcf file installed on my PC can be used on my Mac OS?
Answer: Yes, the file will work on any OS as-is, but if you have Snow Leopard or later, you don't need the client software at all.  OSX has a VPN client built in that will work (you'll still need the settings from the .pcf file ... host, group name, group password, etc.)
Answer: This isn't always true if the port or Tunneling Mode are something other than the defaults in the PCF file.
Answer: I've used the profile pcf file from a Windows to a Linux system, see no reason why it wouldn't work on a Mac.


Rolling One With Cowry Dice

Question: I am playing Parcheesi with cowry shells as dice. I am on the last square and need a roll of one to return the pawn to home. However, with cowry dice, only rolls of 10+grace, 2, 3, 4, 5, 6+grace, 25+grace are possible. An exact throw is required. What is the solution to the problem? Can the 10 throw also stand for 1 in cowry dice?
Answer: Hopefully you are playing Pachisi and not Parcheesi.  If yes, then this answer is accurate.
An ebook by Damian Walker here:
A Book of Historic Board Games
Page 25 - 1.2.7

A grace counts as if were a separate throw scoring 1, in addition to
  the value of the cowries.  Graces are used for entering and moving
  pieces.

As long as you have a grace at then end of your set of rolls you can bring this piece home.
Comment: According to the book, yes.  Cultural variants could be different, that's the difficulty with games as old as this.  Even in North America we have Parcheesi, Ludo, and Sorry that all evolved out of Pachisi.
Comment: So if one rolls 10 or 25, one gets not only an additional throw, but also a grace of 1?

Rolling One With Cowry Dice


Tracking History of changes in Custom fields of custom objects

Question: I want to track the history of 5 fields in custom object. I have selected the Track History checkbox against the corresponding fields in Custom Fields & Relationships section of the object.Still,changes in respective fields are not getting tracked. Is there anything I am missing here ?
Comment: Have you added the related list?
Comment: what type of field(s) are they? you cant track Formula, roll-up summary, auto-number fields, Created By or Last Modified By
Comment: @glls They are number fields. Also,changes from none of the users are getting tracked.
Comment: @Tushar Sharma Thanks! Yes, I forgot to add the related list.Instead I was checking in field activity history.
Comment: @PankajAndhale Then you can accept my answer and close this question.
Answer: So as confirmed in comments you need to add the related list to page layout. The name will be something like "ObjectName History Related List".
Answer: I hope you have followed these steps

Enable Track Field History option under option feature on the Custom object.
Click Set History Tracking in the Custom Fields & Relationships section and checked all those fields for tracking.
Add Custom object History related list on the detail page.
Comment: Yes same steps.
Answer: I had the same issue. My mistake was that I forgot check Track Field History in the object settings. So for view field history you should do these steps:

Check 'Track Field History' in the OBJECT settings:

2. Open Fields and Relationship -> Set History Tracking.
3. Add 'YourObjectName History' related list to page layout


Y.Lang.isUndefined vs typeof undefined, which is better and why?

Question: I was wondering why YUI libs use Y.Lang.isUndefined() even when JS has a built in feature to check type of a variable.
Answer: The reason that method exists is for API consistency -- the YUI team felt it would be weird to leave it out. As LightStyle points out, isUndefined() doesn't do anything special, so you probably shouldn't use it unless you really like the aesthetics.
In fact, only a few of the YUI type checking methods do any actual useful work beyond what you could do natively. Ryan Grove has a detailed walkthrough of these methods (and why you should avoid most of them) in his talk, When Not To Use YUI (youtube.com)
Answer: There is no a true reason in my opinion, it was only for development purposes(it is easier to call a function insted of writing typeof myVar === 'undefined').
L.isUndefined = function(o) {
    return typeof o === 'undefined';
};

From YUI.js source - row 1973


Why does the Akira class have so many torpedo launchers?

Question: The Akira class was a tactically-focused ship designed in response to bigger threats (e.g. the Borg, Dominion, etc.). It has phaser arrays, supposedly has a large fly-through shuttle bay, and has 15--yes, fifteen--torpedo launchers. They are placed in the following order: one forward-facing underneath the deflector dish, a starboard-facing pair in the saucer and a port-facing pair on the other side of the saucer, four forward-facing in the weapons pod, and six aft-facing in the weapons pod.
Why would the Akira need so many torpedo launchers? The Galaxy class could fire up to 10 (I think) torpedoes at a time from a single launcher (out of two: one forward-facing and one aft-facing). The Akira class has not been shown firing nearly as many torpedoes at a time (maybe four at most?) and certainly not from more than one launcher at one time. I understand that the extra launchers facing port and starboard could be very useful (most Starfleet ships--and seemingly most ships of other factions--only have forward- and aft-facing launchers so they have more limited torpedo firing arcs). However, why are the extra launchers (such as the ones in the pod) necessary? If Akira class vessels really did use all of those launchers, wouldn't it burn through its torpedo magazine very quickly? Can the Akira class fire a barrage of torpedoes from those launchers, or are they just backup?
I am looking for a real-world answer (why Alex Jaeger designed the Akira class with 15 launchers) and an in-universe answer (what purpose having 15 torpedo launchers would serve).
Comment: The idea that it's got 15 launchers comes from the designer, and even then from a single interview. In the DS9 guide it's got a far more reasonable "2 launchers".
Comment: It is hard to resist pounding the "Bigger" button… especially if you are a showrunner.
Answer: Target Saturation
I don't know what the real-world answer to this is, but in-universe the reason to have 15 launchers seems simple, target saturation.  If a galaxy class can fire 20 torpedoes at once (assuming fore and aft) then the Akira can dump 150 torpedoes into the void all at once.  With up to 60 at a specific target.  That's a lot to deal with.  It's more likely to overwhelm a ship's point-defense (the ability to use things like phasers to "shoot down" incoming torpedoes) or shields and for things like the Borg that can alter their shields to better resist incoming fire it allows for maximum damage to be inflicted all at once.
Given the design (5 forward, 2 each side, 6 aft) it was probably designed to be used as a "line breaker" in fleet engagements.  It runs in, using it's 5 forward tubes to saturate a single target.  Then it turns (probably maintaining at least 3 tubes on-target apart from the brief period it's at 90 degrees to the opposing fleet) and discharges even MORE tubes worth of torpedoes on ships attempting to pursue it.  Theoretically that's enough torpedoes do destroy anything coming its way.  Even something egregious like a Borg Cube.  It would expend its magazine at a hellacious rate, but as a purpose-built ship it's not meant to be out patrolling for weeks on end and doing this.  It's meant to be in a single engagement, fire off it's torpedoes as quickly as possible, then withdraw with the battle won.   Against weaker individual opponents or multiple smaller ships it's more than capable of sending multiple torpedoes at numerous attackers, preventing it (again in theory) from succumbing to swarm tactics in a general engagement.
Comment: Hi, welcome to SF&F.  Are there any quotes that support this interpretation of how it was designed and was intended to be used?


Accounting for uncertainty in an Elo rating system for Foosball

Question: For a Foosball game at work we implemented a rating system based on the Elo system. Allthough we achieved a sensible result so far, which provided us with a lot of fun (which is the goal) we feel we can do better by:

accounting for uncertainty for new players
removing/ignoring inactive players

Game description
A game is played by 4 players, 2 versus 2. The first team to reach 10 goals with a two point difference wins.
Current rating system
Each player gets an initial rating of 1000 points. When a match is played the outcome of the match is predicted by an adaptation of Elo's rating system. First we predict the probability of team A scoring a single goal before team B (team A wins one 'ball') by
$$ E_A = \frac{1}{1 + 10^{(R_B-R_A)/800}}$$
where $E_A$ is the probability that team A will win this ball and $R_{A,B}$ the sum of ratings of the players in team $A,B$ respectively.
The predicted outcome of the match is then found by 'translating' this prediction to 20 balls:
$$E_{\Delta S} = 20*(E_A-\frac{1}{2}) $$
with $E_{\Delta S}$ the predicted difference in score and $E_A$ the probability of team A winning a ball. If $E_{\Delta S} > 0$ team A is expected to win with a difference of $E_{\Delta S}$ goals, if $E_{\Delta S} < 0$ team B is expected to win with a difference of $E_{\Delta S}$.
The change in rating for the players in this match is then calculated from the difference between the prediction and the actual outcome $\Delta S$:
$$ \Delta r = k\cdot (\Delta S - E_{\Delta S})) $$
With $k$ a parameter to make the changes in rating more agressive. For us a value of $k=10$ works nicely since every goal different from the predicted score earns you $10$ points. A nice round number to remember in the heat of the game.
The ratings for the players in the match are then updated by adding $\Delta r$ to their old rating for the players in team A, and subtracting $\Delta r$ for the players in team B.
Experience
I have not thoroughly examined the performance of this algorithm since I know it has some flaws. However the expected score predictions 'feel' good. They match relatively well with what we expect when playing with/against people we know.
Furthermore in the last 50 of 170 the error in expected score $\epsilon = \mathrm{abs}(E_{\Delta S} - \Delta S)$ was on average 3. This may not be as accurate as it gets, but we consider this reasonable (especially since we have not accounted for the fact that games must end with a 2 point difference).
Question 1
We do notice however that the most inaccurate predictions are given when a player's rating is insanely high or low because he/she has recently achieved a very improbable result (lost or won with a very large score difference). This we would like to solve by predicting how accurate the rating of a player is, and adapting the change in rating accordingly. This could also help the fact that new players start with a 1000 points which is in most cases not accurate at all.
What do you think is a good measure for the accuracy of the current rating and what is an appropriate relation to the ratingchange?
Question 2
We have a high throughput of employees, and so there are a lot of players that no longer play. We can however not simply delete their entries since the average amount of points per player must remain at 1000 so as to counteract inflation/deflation.
What are your ideas on removing players and what should I do with their points?
Thanks
Also rough thoughts and ideas are welcome, we may be able to translate your thoughts and ideas to formulas ourselves.
Comment: This might get (vastly) more attention in stats than it does here in pure math.
Answer: I think you want a version of Microsoft's TrueSkill Ranking System, which has been used for matchmaking for many games on XBox Live. Briefly, each player's skill level is represented with a normal distribution parameterized by mean and variance, which would let you capture the level of confidence in a player's rating. In addition to a bunch of Microsoft papers, it looks like there is some open source software available that could be used to make it easier to implement this.


How do I construct a private aka unregistered DirectShow filter properly (have source code)?

Question: I have created a push source filter using Delphi 6 Pro and the DSPACK DirectShow component library.  I want to use the filter privately so I will not be creating an AX file for a DLL.  Instead I want to create the Filter directly.  I found some threads on this but neither of them show how to construct a private Filter given the filter's constructor's:
constructor Create(ObjName: string; Unk: IUnKnown; out hr: HRESULT);
constructor CreateFromFactory(Factory: TBCClassFactory; const Controller: IUnknown); override;

Here are some threads I found on the subject of unregistered or private DirectShow filters:
http://www.gdcl.co.uk/2011/June/UnregisteredFilters.htm
http://www.progdigy.com/forums/viewtopic.php?p=12304&sid=df52f07f5b00d7ebfac12cb9b9bd9b54
How can I directly embed a DirectShow Push Source filter in an EXE?
The Filter's source code has been directly added to my Delphi project.  But I don't know which Constructor I should use when creating the Filter directly from my main application, and what to pass for the Constructor's parameters.  Can someone tell me what they should be?
Also, do I need to increment the Filter object's reference count like the first thread says to do above and then call Release() on it later when my application terminates?  If so, what is the best way to do this?  Or can I just call Free on the Filter when my application terminates?
Finally, do I need to call CoInitialized() and CoUninitialize() before using my private filter?
UPDATE: Tracing through the classes and the class hierarchy constructor chain for TBCSource, the base class for DSPACK derived filters, it appears that the ObjName parameter is the Filter name and the Unk parameter is the object that owns the filter.  My current guess is that the correct way to create the Filter directly from source would be, given a TBCSource derived class named TPushSourceFilter that is arbitrarily given the filter name 'My Push Source Filter', for example purposes:
TPushSourceFilter.Create('My Push Source Filter', nil, hr);

The first constructor parameter is the Filter name that is used to register the filter, that is, the one you see when perusing DirectShow filters in a tool like GraphEdt.  I believe the second parameter should be NIL because it resolves to an owner data field (FOwner) in the ancestor class named TBCUnknown.  It's sole purpose is to redirect any QueryInterface() calls handled by the base class to the owner object if it is non-NIL instead of applying the query directly to the Filter object in case it's a delegate situation.  I will go ahead with this construction method and see if it works.
Answer: All you need is an instance of the object TPushSourceFilter.Create and obtain IBaseFilter interface from this instance. From there on you add it to the graph just the same way as you do with filters created by CoCreateInstance, then connect pins etc.


DC relay relation with resistance

Question: Is there any method or formula that can be used to find the operating voltage of a coil using the resistance of the coil? If so, is it also applicable to AC coils or any other technique?
Comment: Are you given the current I aswell ? If so you can just use V = IR
Answer: You cannot determine the operating voltage of a coil in this way unfortunately.
The simplest way I can think of to determine the voltage of an unmarked relay would be to connect it to and adjustable power supply (if DC) or variac (if AC). Then simple turn up the voltage until the relay seems to "click" reliably. I would then turn it up a bit more to provide an operating margin.
Answer: Most relay coils carry a specification on how much current must be applied in order to pull in the contacts. Knowing this and the coil resistance, ohm's law then tells you what voltage will be necessary.
Comment: You can't know, brother, because the pull in requires a certain amount of power to overcome spring resistance. Resistance alone isn't enough to work this out. The details will be on the relay datasheet.
Comment: Thanks brother for your answer but i need how can i know about the operating voltage of af a contactoror relay coil by the value of resistance
Comment: does the relay have a nameplate on it with its specifications printed on it?

DC relay relation with resistance


How will having two batteries effect the charging system of my 2004 Honda Civic?

Question: I want to have a 2nd battery to power a 1000w inverter (so I do not have to start the 2004 Honda Civic). How will this affect the charging system? Will both batteries be charged?
Answer: There are several things to consider in this setup. First is the types of batteries to use. Your typical car battery is intended for one main thing, starting the car. There are some other incidentals, but the main thing is providing power for starting.
To perform that duty it is doesn't need to be drawn down low and recharged frequently. But that's what the inverter will do. You will charge it (we'll get to that in a second) and then draw it down low using the inverter. The battery type you want for that is a deep cycle battery. The battery in most cars is not a deep cycle battery.
So you don't want the battery that powers the inverter to be the same type as your main car battery. Which may create an issue if you try to charge it with the one alternator. For one thing, the battery running the inverter will likely be a much larger capacity battery with a different battery chemistry. If it charges faster, trying to charge both at once may be more current than your alternator can handle. Especially if the inverter battery is very low, it will try to pull more current for charging. I don't think the different charging rates will cause other issues, but I would have to think about that one more. Mainly you would have to be sure that your alternator can source enough current to charge both when they are both low. Otherwise you will overheat and damage your alternator.
Some possible solutions:

Separate the two systems completely by installing a second alternator. There are many ham radio operators who run high power amplifiers from their cars which requires multiple alternators, so there are probably kits available to do this. Use the second alternator to do nothing but charge the inverter battery.
Insure your alternator is rated to source enough current to charge both batteries at once when they are both low. For this solution to prevent the inverter from drawing current from the car battery, install a large switch that removes the inverter battery from the car electrical system altogether and only powers the inverter. This way you can always start the car with the on board battery. I'm not sure what the current draw for starting will do to your deep cycle battery, so I would leave the inverter battery out of the line when starting the car. That mean having to throw the switch every time you start the car. Kind of painful.
Completely separate the inverter from the car electrical system and charge the batteries at home. This is the system I use for a system I needed to put together. I have two very large AGM (Absorbent Glass Mat) deep cycle batteries to drive an inverter in the back of an SUV. The batteries are large and heavy and not easily carried about. So pulling them out to charge them can be painful. But, I get 18 hours of high current operation out of the inverter.

These are just some possible solutions. Just make sure that the alternator is capable of what you finally chose to do. Also be sure that the battery chemistry you pick is capable of what your asking of it. Some batteries don't like very short, VERY high current draw, but will do steady draw till the battery is nearly flat very well. Also be aware of what you are switching into and out of your cars electrical system. You don't want to cut off power to the car with the engine running while switches are between the poles for example.
Comment: So is it normal to have to run the car for the inverter to work?
Comment: And please explain the technicalities of why the inverter works when the car is running (ie. inverter running off the charging system?)
Comment: You don't need to have the car running to run the inverter. In the case of the separate system, it won't even be related. If you chose to run the inverter off the car's system, you will need to be sure you're not running the battery so far down that you can't start it again. All of this depends on how you wire it. There is no one answer to this. What might help is a detailed description of what the application for all this is going to be. (How do you plan to use this).
Answer: Well, there's different ways you can do this.

You can have the 2nd battery in the trunk (or wherever) and have your
inverter directly connected to it. Make sure you have a kill switch so that your trunk battery only gets used when you want to use it. The 2nd battery will not be getting charged, since it isn't connected to the vehicle's electrical system. It would be up to you to charge it somehow.
You can have the 2nd battery connected to the vehicle's electrical system so it does get charged. You can still leave it in the trunk (many people relocated their 1 and only battery to the trunk to make room for other components). Your inverter will be powered by both batteries (make sure you leave yourself enough juice to start the car!) and both will get recharged when the vehicle starts.
You can have a more funky setup where only your 2nd battery will power your inverter when the car is off, but both will get recharged when the vehicle is on. The key would be to have your inverter connection to the main battery to only be active when the key is "on" or "acc" (like your radio and most of your accessories), but also have a direct connection to your 2nd battery. This will allow your inverter to run off your 2nd battery when the vehicle ignition is off, prevent your inverter from grabbing power from your main battery, but your 2nd battery would get charged when the vehicle is running.

Depending on which setup you pick, based on your preference and skill level and how much time you want to spend making this happen, #1 is super easy and quick, #2 is a bit more involved, #3 is slightly more involved still. You may need to learn about soldering and using diodes.
Answer: You can certainly use the alternator to charge 2 batteries if you want, but I'm not sure this is actually what you would need. You say you want it so you don't need to start the car to power an inverter, so I guess you have one of these 2 issues:

You don't have enough power to use your inverter for very long
You don't have power with the ignition off

For the first one, just use a higher capacity battery - this saves any sort of complicated wiring and finding a place to mount it etc.
For the second, use an always on connection to your battery (or at least not switched from the ignition)
I had similar requirements (driving a similar inverter and a large sound system for beach parties) and all I needed to do was get a heavy duty battery and a separate switched power line (and a large smoothing cap and some other accessories etc).
Comment: Not to worry, I won't take it personally :-)
Comment: Not sure how down vote happened. I think I "butt voted." It wasn't my intention- hadn't even read the thread yet. If you exit I can withdraw the vote I think.
Answer: Aside from using a deep cycle battery for the inverter, you will want to isolate it from the primary battery for starting the car.
You could use a diode, but there will be a voltage drop.  You could use a relay to connect that battery to the alternator, when the alternator is running, or a switch thrown by the operator when the alternator is running.
Probably the cleanest method is to use a relay/contactor which is located near the alternator, and have a fused run to battery #2. The relay can be controlled by an operator, and should be configured so that if the engine turns off, the relay drops out.


Application is crashing when working with custom model using tflite in flutter. How do i fix it?

Question: I have built a custom tflite model which got converted from Keras hdf5 model. But when using the converted model, while making prediction the application is crashing in android, but when I am using the mobile net tflite model which is downloaded from internet works fine with the application. What changes do I have to make? Whether the problem is in the model conversion or in the application?
I have tried using the inbuilt function by tflite package that supports mobile net and various other nets that are given by tflite, I changed to custom build model prediction function and kept the converted file model. In the first case, it worked, but in the second case, it did not.
Future prediction(File image) async{
  _recognitions= null;
  var recognitions = await Tflite.runModelOnImage(
  path: image.path,   // required
  imageMean: 0.0,   // defaults to 117.0
  imageStd: 255.0,  // defaults to 1.0
  numResults: 2,    // defaults to 5
  threshold: 0.2,   // defaults to 0.1
  asynch: true      // defaults to true
);
  // var recognitions = await Tflite.detectObjectOnImage(
  //   path: image.path,
  //   model: "SSDMobileNet",
  //   imageMean: 127.5,
  //   threshold: 0.4,
  //   numResultsPerClass: 2,
  //   asynch: true
  // );
  print(recognitions);
  setState(() {
    _recognitions=recognitions;
  });
}

I have added 2 models in assets:
  assets:
   - images/webdoctor.png
   - assets/detect.tflite
   - assets/labelmap.txt
   - assets/labels.txt
   - assets/modelPneumonia.tflite

Expected results would be the working of custom model without app crashing.
Answer: I ran into a similar problem and it was a memory leak that crashed the app. I solved it by doing the following:

Add the following to close any resource
@override
void dispose() {
  // you can add to close tflite if error is caused by tflite
  // tflite.close();
  controller?.dispose(); // this is to dispose camera controller if you are using live detection
  super.dispose();
}

Run the Command: flutter clean

Rebuild your project

P.S. It would be nice if more details on the error from the debug console was given.
Answer: Keeping extra lines on labels.txt or labelmap.txt would be an issue. Please make sure you don't keep new lines.


questions about construction of splitting fields of polynomial $\langle x^3-2\rangle$ over $\mathbb{Q}$

Question: I'm thinking about using the construction of splitting field by quotient out the irreducible polynomial every time to construct the splitting field of polynomial $\langle x^3-2\rangle$ over $\mathbb{Q}$, so we should quotient out by the irreducible polynomial $\langle x^3-2\rangle$ the first time, my question is how do we know it's isomorphic to $\mathbb{Q}(\sqrt[2]{3})$ but not $\mathbb{Q}$ adjoining other roots of the irreducible polynomial?
Answer: The polynomial $x^3-2$ has three distinct roots, one real and two complex. So $\mathbb{Q}(\sqrt[3]{2})$ cannot be the splitting field, because it's a subfield of the real numbers.
If $\omega$ is a complex non real number such that $\omega^3=1$, then you know that the roots of $x^3-2$ are
$$
\sqrt[3]{2},\quad \omega\sqrt[3]{2},\quad\omega^2\sqrt[3]{2}
$$
(because $\omega^2=\omega^{-1}=\bar{\omega}$ is the other complex cube root of $1$). Since
$$
\omega=\frac{\omega\sqrt[3]{2}}{\sqrt[3]{2}}
$$
belongs to the splitting field, you have that the splitting field contains
$$
\mathbb{Q}(\sqrt[3]{2},\omega)
$$
but, obviously, this field contains all roots of $x^3-2$ and so is the splitting field.
Comment: Thank you! I understand the part that the splitting field should be $\mathbb{Q}(\sqrt[3]{2},\omega)$, however, I'm just wondering what is Q\ isomorphic to? because it should be isomorphic to one of Q adjoining one of the three roots of the polynomial, but I don't know why is it isomorphic to Q adjoining $\sqrt{3}{2}$ rather than Q adjoining other two roots of the polynomial? Thanks so much!
Comment: @JoeyCheng If you add just one root (no matter which one), you get isomorphic fields, all isomorphic to $\mathbb{Q}[x]/\langle  x^3-2\rangle$


Live strings on Epiphone sg special 2

Question: Iv'e just purchased a Epiphone sg special 2 and a fender mustang 1 v2 amp.
The problem I've got is when I connected it all up I fretted a string it played a note as if the strings were live. When I let the string go it sounded again. Is it the guitar or amp or just amp settings.
Comment: This seems perfectly normal - when you fret a string you should be able to hear it play. Can you give more details.
Comment: sounds like what happens when the gain is up high, which would be an amp setting.
Comment: Thanks for the replies. I'm a complete novice only second time holding an electric guitar.I set all the amp dials at one then turned up the master till I got a response I then fretted a string and it sounded just like plucking a note.I then thought the previous owner might have dialled in an affect but I can't tell. A little knowledge is dangerous so what is none.
Comment: this is a feature of guitars to some extent. Some few guitarists leverage this to an extreme, such as Stanley Jordan. The following is a link to Stanley Jordan playing in a Trio Live in Paris. It may look like a piano thing, until about 2:20 mins (Feelings of Inadequacy Warning(tm): https://www.youtube.com/watch?v=p9Ae3R6QP6c
Answer: With an electric guiatr hooked up to an amp with medium to high gain, fretting a string (otherwise known as hammering-on) will make the note sound, almost exactly as if you had picked or plucked that string.
The same happens when you remove your finger (pulling off)
This is generally considered a very good thing in playing electric guitar, as it allows smooth legato runs, faster notes and runs and even allows you to play a melody line using hammer ons and pull offs while picking a bass line, for example.
If you don't like it, you need to back off the gain, and perhaps learn to damp the unneeded strings.
Answer: If you press a string down gently, more than likely, unless the amp and guitar are extremely loud, it won't happen. Likewise, taking that finger off, gently, will stop the sound of the open string. Unless the fingers are sticky!
It's hammer-on for the first effect, and if you do want the string to sound again as you pull your fretting finger slightly to one side, it's pull-off. Both very good techniques that guitarists use all of the time.
Comment: Thanks again for the info. I reset the amp to factory settings and it seems to have done the trick.

Live strings on Epiphone sg special 2


Symmetric group irreps in tensor products of exterior products of the standard representation

Question: Let $\mathbb{C}^n = V + \mathbb{C}$ be the defining representation of the symmetric group.  Is there a nice formula for how $\Lambda^i V \otimes \Lambda^j V$ splits into irreps?
Answer: Congratulations, you have asked one of the few questions of this type for which there is a positive answer. Such a formula is the main result (Theorem 2.1) of Remmel's paper "A formula for the Kronecker products of Schur functions of hook shapes".
A few points of vocabulary to get you oriented: The irreducible representations of $S_n$ are indexed by the partitions of $n$. The partition $\bigwedge^k V$ corresponds to the partition $(n-k, 1,1,\ldots, 1)$ where there are $k$ $1$'s. These partitions are called "hooks". (Note the degenerate cases: $k=0$ is $(n)$ and gives the trivial representation; $k=n-1$ is $(1,1,\ldots,1)$ and gives the sign representation.) The tensor product of $S_n$ representations corresponds to the combinatorial operation known as Kronecker product. So the title of Remmel's paper tells you that it is answering your question, and googling on "Kronecker hook" will turn up more references.
Remmel defines a double hook to be a partition of the form $(q,p, 2, \ldots, 2, 1,\ldots, 1)$ where there are $k$ occurrences of $2$ and $\ell$ occurrences of $1$. His result is that the only irreps that appear in $\bigwedge^i V \otimes \bigwedge^j V$ are hooks and double hooks, that the multiplicities with which they appear are $\leq 2$, and he gives an exact formula for which ones appear with which multiplicities.
Comment: +1 for the first sentence. Alas.
Comment: Is there something similar for symmetric powers ?
Comment: David, Thanks for your answer.
A typo
[The partition $\bigwedge^k V$ corresponds to the partition]-->
[The representation $\bigwedge^k V$ corresponds to the partition]


Spin tool in Blender 2.92.0 rotates only around z-axis by default

Question: The documentation says that the spin tool will extrude faces along an arc rotating around the axis of the viewport. No matter which axis my viewport is oriented to, and no matter where my 3D-cursor is, my spin tool makes an arc around the z-axis. In order to spin around the x- or y-axes, I have to open the Spin menu and type in a 1 for the axis I want and type in a 0 for the z-axis.
Answer: Click outside to use view axis.

Spinning around camera view, undo, then TOP ortho.
There may be some magic to using the gizmo that appears if you click a plus, revealing the default Z axis path, but it is a slippery beast and TBH I have no idea how to control it. (apart from moving the pivot point)  Perhaps someone will add a better answer re this..
So I resort to align the view to axis I wish to spin around, then click outside the gizmo and spin around similarly to rotation.
Comment: am going to feel so embarrassed if someone posts how to use the gizmo and it is easy, I usually end up spinning on at least 2 other axes than the one  I want by the time I get there.  I rarely use the UI,.
Comment: Yeah the usability is lacking a bit - I always use the pop-up menu to control it :).


"Whosoever" in John 3:16

Question: It is correct to suggest that "whosoever" can be translated "the believing ones" or "the ones believing" and still maintain the the seeming Greek construction of πᾶς ὁ πιστεύων as tending towards a generalization, that is, as in "anyone who believes," instead of it being interpreted as referring to a specific class or group of persons at the exclusion of others?  Thank you.
Comment: See related: [What does the word "world" mean in John 3:16, in the light of John 17:9?](https://hermeneutics.stackexchange.com/q/7374/)
Answer: Does πᾶς ὁ πιστεύων refer to a specific class of people?
Not in the context, which provides no class but simply 'anyone who believes.' Rather, it is in the universality of the avaialability of His grace, that this doctrine finds its great power; in the fact that salvation is open to all men, for whom Christ died—everyone—if they would but accept it.1 Jn 2:2; 2 Pet 2:1
In fact, it's clear that a general 'anyone who believes' is the only one consonant with the immediate context:

John 3:1-5 (DRB) (emphasis and italics mine)
And there was a man of the Pharisees, named Nicodemus, a ruler of the Jews. 2 This man came to Jesus by night, and said to him: Rabbi, we know that thou art come a teacher from God; for no man can do these signs which thou dost, unless God be with him. 3 Jesus answered, and said to him: Amen, amen I say to thee, unless a man be born again [same word for 'from above'], he cannot see the kingdom of God. 4 Nicodemus saith to him: How can a man be born when he is old? can he enter a second time into his mother's womb, and be born again? 5 Jesus answered: Amen, amen I say to thee, unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God.

So this is speaking in general terms, since "a man" or "any" (τις—v. 5) never refers to a specific class of people without qualification such as here.
It is in this context that Jesus distinguishes between the hypothetical believing man, who accepts the word and keeps it, Mt 13:8-9 (also general) and he who does not believe. Anyone (τις—v. 5). Mark 16:16 is the same teaching, except in the singular instead of plural. But doesn't grammatically or contextually change any meaning. It is in this universal spirit that Jesus says other things generally, such as 'he that endures to the end,' (Mt 24:13) which become meaningless as mere descriptions of smoe select few, and not warnings. And which would also contradict the explicit meaning given (Lk 21:19; Mt 10:22).
In short, the elect are only those known to God and perhaps someone inspired by Him directly with some revelation. Only God knowns who eventually endures to the end. From only God knows who truly believes and who will be saved. Only in this sense could we take warning passages as descriptive on God's part.
For us they remain incentives and warnings and commands.
Comment: Spooky mysterious downvoters please give the reasons you are downvoting. Thanks.
Answer:
ινα πας ο πιστευων

πιστευων is the participle and is preceded by the definite article. Thus the collocation should be rendered 'the believing', that is, those persons who have the characteristic of believing. It is not one act of some kind, it is a continuous matter; a characteristic of them.
Young's Literal has :

everyone who is believeing

and the EGNT (Englishman's Greek New Testament, interlinear) has :

everyone who believes

Both Young and the EGNT render the rest of the sentence as 'may not perish'.
The statement :

'God so loved the world that everyone the believing may not perish'

contains only one class of persons - the believing.
And those believing form a world that shall not perish.
Comment: About this, Wallace says: 'The idea seems to be both gnomic and continual: "everyone who continually believes." This is not due to the present tense only, but to the use of the present participle of πιστεύω , especially in soteriological contexts in the NT.' See [*The Participle*](https://bible.org/article/participle) by Daniel B. Wallace.
Comment: @PaulVargas Excellent. Thank you. I have just ordered the book from Amazon.
Comment: That's great. I bet you will have [lots of fun](http://www.beingtaught.org/ggbb/).
Answer: No, it would not be proper to interpret whosoever as meaning "the believing ones", if for no other reason than the word whosoever doesn't actually appear in the Greek text:

πᾶς ὁ πιστεύων εἰς αὐτὸν

The phrase sounds clumsy in English, but it literally reads "the everyone believing in Him", perhaps better rendered as:

everyone believing in Him

The verse does not state whoever or whosoever (ὅς), but rather everyone (πᾶς).  Also πιστεύων is the participle "believing" and not some other form of the verb believe (πιστεύω), but for stylistic reasons the phrase is usually translated:

everyone that believes in Him

or

everyone who believes in Him

The presence of a participle here could be understood mean that the "believing" is an on-going activity, and not just some one-time event (e.g. some single affirmation of belief in the past).
All of the available Greek manuscripts show the phrase as indicated above.
Answer: Translating πᾶς ὁ πιστεύων as "the believing ones" leaves out the πᾶς.  You could translate the phrase "all who believe" or "everyone who believes."  Everyone and whoever is better because the particle is singular.  To translate πᾶς and leave the participle singular you need a word like every in there, i.e. "every believing one," but if you use the English particle, the English translation seems to come out awkward.
Answer: To understand the term whosoever believes we need to understand who the true believer is.
The true believer is one who seeks the honour that comes from God only, He is thirsty for God and His righteousness. Many say they believe. But not everyone that says Lord, shall enter into my kingdom but they that do the will of my father in heaven.
John 5:44

44 How can ye believe, which receive honour one of another, and seek
not the honour that cometh from God only?

Whosoever believes: Jesus reminds us that there were many widows in the days of Elijah but he was sent to non of them but to the widow of Zeraptha. Not everyone that calls himself a believer is a believer.
Luke 4:25,26, 27

25 But I tell you of a truth, many widows were in Israel in the days
of Elias, when the heaven was shut up three years and six months, when
great famine was throughout all the land;
26 But unto none of them was Elias sent, save unto Sarepta, a city of
Sidon, unto a woman that was a widow.
27 And many lepers were in Israel in the time of Eliseus the prophet;
and none of them was cleansed, saving Naaman the Syrian.

Jesus knows his own from the beginning, for many are called but few a called, the believer is called to walk through the narrow way.
Whosoever believes will walk with him all the way.
John 6:53,54,56-58,60-66

53 Then Jesus said unto them, Verily, verily, I say unto you, Except
ye eat the flesh of the Son of man, and drink his blood, ye have no
life in you.
54 Whoso eateth my flesh, and drinketh my blood, hath eternal life;
and I will raise him up at the last day.
56 He that eateth my flesh, and drinketh my blood, dwelleth in me, and
I in him.
57 As the living Father hath sent me, and I live by the Father: so he
that eateth me, even he shall live by me.
58 This is that bread which came down from heaven: not as your fathers
did eat manna, and are dead: he that eateth of this bread shall live
for ever.
60 Many therefore of his disciples, when they had heard this, said,
This is an hard saying; who can hear it?
61 When Jesus knew in himself that his disciples murmured at it, he
said unto them, Doth this offend you?
62 What and if ye shall see the Son of man ascend up where he was
before?
63 It is the spirit that quickeneth; the flesh profiteth nothing: the
words that I speak unto you, they are spirit, and they are life.
64 But there are some of you that believe not. For Jesus knew from the
beginning who they were that believed not, and who should betray him.
65 And he said, Therefore said I unto you, that no man can come unto
me, except it were given unto him of my Father.
66 From that time many of his disciples went back, and walked no more
with him.

To properly understand, what it means whosoever believes we must also look at it from the context of the rest of the scripture.
Luke 13:23,24

23 Then said one unto him, Lord, are there few that be saved? And he
said unto them,
24 Strive to enter in at the strait gate: for many, I say unto you,
will seek to enter in, and shall not be able.

You see it is at a cost:
Matthew 7:13,14

13 Enter ye in at the strait gate: for wide is the gate, and broad is
the way, that leadeth to destruction, and many there be which go in
thereat:
14 Because strait is the gate, and narrow is the way, which leadeth
unto life, and few there be that find it.

Surely whosoever believes will not walk in the way that leads to destruction. From the scriptures we learn first the believers are few, because it costs them walking the narrow way, the way of holiness.
Matthew 16:24,25

<code>24 Then said Jesus unto his disciples, If any man will come after me, let him deny himself, and take up his cross, and follow me.

25 For whosoever will save his life shall lose it: and **whosoever** will lose his life for my sake shall find it.
</code>

Whosoever believes, must be willing to lose his life for Christ's sake. Faith is a day today affair. That's why we must believe all the way:
Jude 1:5
5

I will therefore put you in remembrance, though ye once knew this,
how that the Lord, having saved the people out of the land of Egypt,
afterward destroyed them that believed not.

It is all at a cost. It calls for counting the cost.
Luke 14:27,28

27 And whosoever doth not bear his cross, and come after me, cannot be
my disciple.
28 For which of you, intending to build a tower, sitteth not down
first, and counteth the cost, whether he have sufficient to finish it?

It is a call to walk with him in the way of holiness, a call to to whomsoever to walk in holiness
Isaiah 35:8-10

8 And an highway shall be there, and a way, and it shall be called The
way of holiness; the unclean shall not pass over it; but it shall be
for those: the wayfaring men, though fools, shall not err therein.
9 No lion shall be there, nor any ravenous beast shall go up thereon,
it shall not be found there; but the redeemed shall walk there:
10 And the ransomed of the LORD shall return, and come to Zion with
songs and everlasting joy upon their heads: they shall obtain joy and
gladness, and sorrow and sighing shall flee away.

Galatians 5:24

24 And they that are Christ's have crucified the flesh with the
affections and lusts.

It is not just a wishy washy affair. It calls for a death to self:
Galatians 2:20

20 I am crucified with Christ: nevertheless I live; yet not I, but
Christ liveth in me: and the life which I now live in the flesh I live
by the faith of the Son of God, who loved me, and gave himself for me.
Comment: "To understand the term whosoever believes ..."  The term "whosoever believes" is not actually found in the literal Greek text.
Comment: This is a helpful answer, however it appears you have answered this question by appealing to other biblical texts, i.e. interpret the passage through other passages. This is helpful, however I believe we do need to start with grammatical/translational issues, we need to make sure we understand the greek correctly before we move on to understanding this verse in the context of other verses.

"Whosoever" in John 3:16


Linking a library with a project relative path in Visual studio 2008

Question: Linking a library with a project relative path in Visual studio 2008
Answer: It will by default set it to a relative path, if it's within your project directory. I've seen cases where that does break though (either older versions, or possibly when you move it around) so you should just be able to edit the .*proj file and manually change the path.
This question raises a flag for me though, since it seems like possibly you're linking to a non-standard .dll that is outside of your project, and thus not in source control. You should generally be able to check out a fresh copy of a project and compile it.. and if you're linking to random DLL files in specific locations that are not included, it's going to cause issues in the future..
Comment: I want to do this so I can be able to move the project around without resetting all the paths.
Answer: use a relative path from your vcproj (or maybe sln) file.  Alternatively, put this path into the library search path.  Alternatively again, make it explicitly relative to one of the project macros (e.g. $(ProjectDir)).  The list of these macros can be seen when you pop open the configuration item using the little dot-dot-dot icon on the right side of the field (then click "macros").


Are these diagrams the same?

Question: When computing the propagator of the $Z$ boson at one-loop level in the Standard Model, should we consider both of these two diagrams (where $\varphi^\pm$ are the charged Goldstone bosons) or are they the same diagram and should only be considered once?
Answer: Think about how Feynman diagrams originate from the perturbative expansion. These two diagrams will come from different terms in the expansion, so they are not the same.

Are these diagrams the same?