Actually, i have 540x46 matrix, (540 observations and 46 features) and after using PCA by considering 95% variance, it is reduced to 540x12 matrix.  So, is it possible to know which 12 features from 46 are they? and order of these 12 features according to dominance level?  I hope now question is clear and please let me know if you need any other information.
I'm new to feature selection and I was wondering how you would use PCA to perform feature selection. Does PCA compute a relative score for each input variable that you can use to filter out noninformative input variables? Basically, I want to be able to order the original features in the data by variance or amount of information contained.
I was writing a program in C++ to find all solutions of ab = c, where a, b and c together use all the digits 0-9 exactly once. The program looped over values of a and b, and it ran a digit-counting routine each time on a, b and ab to check if the digits condition was satisfied.  However, spurious solutions can be generated when ab overflows the integer limit. I ended up checking for this using code like:  unsigned long b, c, c_test; ... c_test=c*b;         // Possible overflow if (c_test/b != c) {/* There has been an overflow*/} else c=c_test;      // No overflow   Is there a better way of testing for overflow? I know that some chips have an internal flag that is set when overflow occurs, but I've never seen it accessed through C or C++.    Beware that signed int overflow is undefined behaviour in C and C++, and thus you have to detect it without actually causing it. For signed int overflow before addition, see . Is there a way to see the pokestops and gyms on a map? I'm on vacation on a pretty rural area and there is only 3 pokestops and a gym around me. I wonder how many pokestops and gyms are near my house in another city.   Is there a way to see pokestops and gyms in other places in a map (preferably online)?    There seems so be loads of websites linked. While posting your own website is allowed (as long as it answers the question properly) please keep in mind that stating your affiliation is required (Add something like "Disclaimer: I own this website" to the end of your answer) in order to avoid being spam flagged. Most of the time, it should be really easy to determine who is my ally and who is not. The people who try to kill me are most likely my foes, whereas the people who entered the dungeon with me are probably my allies.   But sometimes it’s not that simple. What if one of my party members got replaced by an evil doppelganger, who plans to kill me in the near future? What if one of my allies infiltrated the court of the evil king and I accidentally have to fight her, while she is (unbeknownst to me) under the effect of a  spell? What if a character fell in love with the BBEG and just wants to save him from himself, while the BBEG hates the character and actively tries to murder him?  Most spells and abilities that affect others specify the targets as “creatures” or “willing creatures”. Some explicitly affect allies only. That’s why I want to know, how to determine who’s allied with whom. Do I have to think that someone is my ally for someone to count as my ally? Does someone else have to believe to be my ally in order to count? Do both of us have to agree on being allies? Is there an objective observer who determines who’s allied? Can Person A be the ally of Person B, while Person B is not the ally of Person A?  There are many examples for spells/abilities that care about allies, among others:   the Exalted Champion feature from the  (SCAG, p. 132-133), that grants allies within 30 feet advantage on Wisdom saving throws. the Inspiring Surge feature from the  (SCAG, p. 128), that allows one or two allies within 60 feet to make a melee weapon attack as a reaction.   With features like this, you could accidentally affect someone who’s not actually your ally. You could fail to affect someone who is actually your ally, but you don’t know it (yet). Or you could affect someone who doesn’t want to be affected (because they don’t want to be allied with you). This all depends on the interpretation of the word “ally”. I’m not sure if "ally" is a defined game term (but I don’t think so), or if I have to rely on the dictionary definition. That’s why I want to ask:  How do I determine who’s allied with whom? I have been experiencing an issue that once I have a material created and looking the way I want it, I cannot seem to export it correctly with the textures mixed.  I don't know the correct words to use, but in blender I have the material created using the nodes editor, and I have placed two textures inside of there (one for the rock texture and one for moss, my object is a rock). When I export this model and import to Unity (the game engine I am using), I find a materials folder but the material inside of it does not have the textures assigned, it's just a plain white material?  How can I export my material from blender in a way that it will allow me to import it WITH TEXTURES into Unity? What settings should I be using to shoot "Supermoon"? How to avoid bad box with long words with no hyphenation? Your communities list is not visible in mobile web on site where you don’t have an account If you don’t have an account for some site, you can still see a list of your communities via top bar menu of this site, e.g. on 3D Printing:        But this works only for full web, in mobile web «sign up or log in» is shown:        When you have an account then the list of your communities is shown even for mobile web: EXTRA PROBLEM I have NEI on minecraft with some other mods and NEI is supposed to have a saves thing on the left, and items on the right. The only thing on the left is the options. I want to see the saves and time changing options too.  Cheat Mode When I click on a item to get it it keeps showing me the recipe. Though in the options menu from NEI it is on cheatmode. I saw another post saying I need to change something to this lockmode=-1 or cheatmode=2 but it is already that way. That didn't work how do i get it to give me the items and also recipe when I press R. I'm studying for an abstract algebra exam and one of the review questions was this:     Let $X$ be a set, and $\mathcal P(X)$ be the power set of $X$. Consider the operations $\Delta$ = symmetric difference (a.k.a. "XOR"), and $\bigcap$ = intersection.   a) Does $\Delta$ and $\bigcap$ make $P(X)$ into a ring?   b) If so, is it a ring with unity?   c) Is the ring commutative?   d) Is it a field?   For parts a) and b), I think it does form a ring with unity, but I'm not quite sure how to get started on proving it.   For part c), it is a commutative ring since $\mathcal P(X)$ is closed under symmetric difference and intersection, right?  Not even sure how to get started on d).  I'd really like to understand this question fully, so any kind of input would be tremendously helpful. Thank you! How to use early stopping properly for training deep neural network? This is a  about DNS server administration.   I have one hundred or so domains. All of these domains need to be configured identically, but it seems like a huge waste of time to have to configure a new zone and/or zonefile for every one of these domains. There has to be a better way to automate this!  I think I'm on to something...if I create a zone called ., or use some other feature in my DNS software to always return a specific IP when an A record is requested, this seems to get me pretty close to my desired end result. My server is responding authoritatively to the requests and it's so much easier to manage!  This was working great until nameserver validation software started checking these domains. I figured out that I can make most of the errors go away by adding NS records, but my software won't let me put more than one SOA record in the same zone file.  How do I work around this multiple SOA record problem? Is it possible to remove "Show Desktop" from the Alt+Tab application switcher? if I write,  #!/bin/bash echo "foo"   or  #!/bin/sh echo "foo"   both yields same. I have seen some scripts starting with #!/bin/sh or #!/bin/bash. Is there any difference between them? Example of a recursive set $S$ and a total recursive function $f$ such that $f(S)$ is not recursive? Browsing wikipedia, I stumbled on the following: "The image of a computable set under a total computable bijection is computable." Given the form of the theorem, there must be some example of a example of a recursive set $S$ and a total recursive function $f$ such that $f(S)$ is not recursive (otherwise the statement would have presumably been stronger). But I'm having difficulty dreaming up a case where this happens. Prove that if $A$ is an infinite set then $A \times 2$ is equipotent to $A$ I want to prove that if $A$ in an infinite set, then the cartesian product of $A$ with 2 (the set whose only elements are 0 and 1) is equipotent to $A$.  I'm allowed to use Zorn's Lemma, but I can't use anything about cardinal numbers or cardinal arithmetic (since we haven't sotten to that topic in the course).  I read a proof of the fact that if $a$ is an infinite cardinal number, then $a+a=a$, which is something similar to what I want to prove.   Any suggestions will be appreciated :) How to find the running network services and the port and user I want to find a list of all network services running on my system, including details of the port and services and the users. I know that I need to use netstat, ps and fuser. but I don't know how to write the command. Do I need to write a shell script to find all of them? or I can use in a line of commands? Thanks for your help. I have an excel spreadsheet with header and survey drill data. Header data contains hole ID, and location coordinates, and the survey data contains related downhole survey with Distance, Azimuth and Dip values.   Since I know the hole location and surface elevation, I would like to be able to convert the survey table to XYZ coordinates as well.  Does anyone has a function / procedure / example?  (VB &amp; ArcObjects)  Header Data:    Survey Data: Arrays in Java and how they are stored in memory int fn();  void whatever() {     (void) fn(); }   Is there any reason for casting an unused return value to void, or am I right in thinking it's a complete waste of time?  Follow up:   Well that seems pretty comprehensive.  I suppose it's better than commenting an unused return value since self documenting code is better than comments. Personally, I'll turn these warnings off since it's unnecessary noise.    I'll eat my words if a bug escapes because of it... I want to do:  cat update_via_sed.sh | sed 's/old_name/new_name/' &gt; new_update_via_sed.sh   in my program.  But I want to use variables, e.g.  old_run='old_name_952' new_run='old_name_953'   I have tried using them but the substitution doesn't happen (no error). I have tried:  cat update_via_sed.sh | sed 's/old_run/new_run/' cat update_via_sed.sh | sed 's/$old_run/$new_run/' cat update_via_sed.sh | sed 's/${old_run}/${new_run}/'