for dir in equil[0123] could iterate over folders of equil0, equil1,equil2 and equil3. But if I have folders with name number more than 10, e.g. equil23, how to properly refer to them? How the separator is recognised in equil[0123]?
What is the difference between a[bc]d and a{b,c}d? Why do people use a{b,c}d when there is already a[bc]d?
Why should boostrap sample size equal the original sample size? When searching the internet on the sample size of for boostrap samples I generally find that the size should equal the original sample size. However, I can't find any explanation on why this should be the case.   In what way is it bad to use a smaller sample size? Is it always better to use a larger sample size?   Some of the sites which report this: How do you properly use namespaces in C++? How to compute the marginal likelihood given two multivariate Normal distribution? Given that $a$~$\mathcal{N}(\mu, \Sigma)$ and $\mu$~$\mathcal{N}(0, \sigma^2 I)$, Is $p(a|\Sigma, \sigma)=\int p(a|\mu, \Sigma)p(\mu|\sigma)d\mu$ again a Normal distribution? And how to estimate the mean and variance respectively? Thanks a lot! I am extremely poor in solving a problem quickly, which leaves me doing badly in olympiads and other contests. But, if I just don’t give up on a problem, no matter how much time it takes, I usually end up solving it. To have a future in mathematics or physics, is it necessary for me to excel at contests, because these days children excelling at contests have an advantage over those who don’t (not complete advantage, but advantage nonetheless)? Simple newbie help page about avoiding "Thanks" How can I quickly create a large file on a Linux () system?   will do the job, but reading from /dev/zero and writing to the drive can take a long time when you need a file several hundreds of GBs in size for testing... If you need to do that repeatedly, the time really adds up.  I don't care about the contents of the file, I just want it to be created quickly. How can this be done?  Using a sparse file won't work for this. I need the file to be allocated disk space. Allow users to leave an anonymous comment when voting I don't know if people don't explain why they up or down vote because they don't care or because they don't want the person to know they voted on an answer (or question)... But, it might be nice to be able to leave a comment anonymously as to why it was voted.  It could give us more insight as to people's thoughts on posts.    Really, I think this would come into play a lot more dealing with down votes more than up votes, but I could see it being beneficial in both situations.   See also Fast, accurate 2d collision I'm working on a 2d topdown shooter, and now need to go beyond my basic rectangle bounding box collision system.  I have large levels with many different sprites, all of which are different shapes and sizes. The textures for the sprites are all square png files with transparent backgrounds, so I also need a way to only have a collision when the player walks into the coloured part of the texture, and not the transparent background.  I plan to handle collision as follows:   Check if any sprites are in range of the player Do a rect bounding box collision test Do an accurate collision (Where I need help)   I don't mind advanced techniques, as I want to get this right with all my requirements in mind, but I'm not sure how to approach this. What techniques or even libraries to try. I know that I will probably need to create and store some kind of shape that accurately represents each sprite minus the transparent background.  I've read that per pixel is slow, so given my large levels and number of objects I  don't think that would be suitable. I've also looked at Box2d, but haven't been able to find much documentation, or any examples of how to get it up and running with SFML. Possible Duplicate:          The  describes the expansion of the $n$th power of the sum $(a+b)$:  $$(a+b)^n = \sum_{k = 0}^n {n\choose k}a^kb^{n-k}$$  In calculus, there is a generalization of the product rule called , which describes the expansion of the $n$th derivative of the product of two functions $f$ and $g$:  $$(fg)^{(n)} = \sum_{k = 0}^n {n\choose k}f^{(k)}g^{(n-k)}$$  It's not difficult to prove using the product rule and induction, what I'm really trying understand here is why the formula is true. Is there a way to prove it using the binomial formula? How are these two formulas related? Is there a combinatorial proof for Leibniz's rule like there is for the ?   I understand this question is a bit vague, but I hope you'll agree that these two formulas look so similar it just feels like there should be some relation between the two. Of course this is not necessarily true, but I'm hoping it's not just a crazy coincidence. Can't access global variable inside function Why separate Stack Exchange accounts? I understand the reason why Stack Exchange has different sites to separate  from  or . I understand too why the reputation is associated on each site.   Why do I have to create a new  for each web site? I know that when I create a new account, it is automatically associated to my other accounts. But, is there a reason why, when I originally create a user on the first site, I can't go on another site with this user? Solve for $A,B$: $\mathrm{LCM}(A,B)=168$, $\mathrm{HCF(A,B)}=12$ Keras CNN with low/constant accuracies Train loss and accuracy In theory, is it possible that the loss on the train set will increase together with the train set accuracy? (in the normal case the train set loss should go down) And vice versa, can the train loss decrease along with the accuracy?   Note: This is obviously different than the classic underfit / overfit cases which are easier to grasp. Show that $PF.PG=b^2$ in a hyperbola If the normal at P to the hyperbola $\frac {x^2}{a^2}-\frac {y^2}{b^2}=1$ meets the transverse axis in G and the conjugate axis in G' and CF be the perpendicular to the normal from the center C then show that $$PF.PG=b^2\space and \space PF.PG'=a^2.$$ We know that the equation of the normal at parametric point $P\equiv(a\sec\theta,b\tan\theta)$ is given by  $$a\,x\cos\theta+b\,y\cot\theta=a^2+b^2$$   Equation of the transverse axis is $y=0$ and that of the conjugate axis is $x=0$.   Hence   $$G\equiv(\frac {a^2+b^2}{a}\sec\theta,0), \, G'\equiv(0,\frac {a^2+b^2}{b}\tan\theta)$$  C is the origin and CF is perpendicular to the normal. Hence   $$ CF\equiv b\,x\sec\theta-a\,y\tan\theta=0\implies y=\frac {b\,x\sec\theta}{a \tan\theta}$$   Substituting this in the equation of the normal we get   $$a\,x\cos\theta+b \,\cot\theta\,\frac {b\,x\sec\theta}{a\,\tan\theta}=a^2+b^2\ $$   implies  $$ (a^2 \cos\theta \sin^2\theta+ b^2\cos\theta)x=(a^2+b^2)\sin^2\theta$$  After finding the coordinates of F, the calculation becomes very complicated. So is there an easier way to approach the problem? I would love to see a pure geometric solution to this problem. Is there a way to mix LIKE operator with IN ? Something Like  SELECT Id FROM Account WHERE Name LIKE IN:nameList   Where nameList is list of String? Is this is possible ? (I can make a dynamic query by doing OR with all the elements, but was looking for a more elegant way to do this) Why doesn't Normal[] work on GeometricTransformation? Tips to extend battery life for laptops and notebooks This question is present as a matter of historical interest.  While you are encouraged to help maintain its answers, please understand that "big list" questions are not generally allowed on Ask Ubuntu and will be closed per the .   It is possible to greatly extend the usage time of a laptop or netbook running on battery by disabling various services and installing various packages.   What tricks or tips do people have for getting an extra hour or two out of their batteries? Windows 7: Disable Lock Workstation After 10 Minutes Using Group Policy On my Windows 7 PC the system becomes locked after 10 minutes of inactivity. Usually I would find this setting next to the screen-saver configuration. The setting is grayed out, however.  I think this is because of corporate group policy. As I am an administrator on this computer I should be able to reconfigure the group policy setting using gpedit.msc.  What is the group policy setting that I need to change to prevent automatic locking of my workstation?  Edit: I don't have configured a screen-saver. I also want to continue to be able to lock the workstation manually. load() method deprecated?