Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-15 Thread sympy
Comment #27 on issue 2624 by asmeu...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 I guess it's because of the gcd behavior on rationals: In [64]: gcd(1, S.Half) Out[64]: 1/2 You have to use Mul(evaluate=False). See issue 1497

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-10 Thread sympy
Comment #25 on issue 2624 by ness...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 Somehow this seems to have been lost: Thanks for the tip. Factor_terms has the unfortunate effect of turning things like a/2 + 1 into (a+2)/2 - first

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-05 Thread sympy
Comment #22 on issue 2624 by smi...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 factor_terms was written for such purposes as this; to give a non-destructive simplification of exressions. In fact, it works in this case

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-05 Thread sympy
Comment #23 on issue 2624 by alex.ebe...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 [...] From a user's perspective: factorized is better than expanded. If the function is cheap and no one finds a case in which such call would lead

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-04 Thread sympy
Comment #20 on issue 2624 by alex.ebe...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 I think this example here gives a point for adding a call to expand_mul(). However, as I am not familiar with the implications of such a call, I

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-03 Thread sympy
Updates: Status: Fixed Comment #15 on issue 2624 by smi...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 perhaps a new issue for the poor simplification mentioned in http://code.google.com/p/sympy/issues/detail?id=2624#c3

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-03 Thread sympy
Comment #16 on issue 2624 by alex.ebe...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 It's actually almost there - performing the integral in question and then using simplify evaluates correctly. Thus, simplify(integrate(exp(-x**2

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-03 Thread sympy
Comment #17 on issue 2624 by ness...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 The integration code does not simplify results it produces, so this behaviour is expected. -- You received this message because you are subscribed

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-03 Thread sympy
Comment #18 on issue 2624 by alex.ebe...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 If this is desired behavior there might be no point in opening a new issue for the poor simplification. -- You received this message because you

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2012-02-03 Thread sympy
Comment #19 on issue 2624 by ness...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 There is room for discussion, obviously, but I think at some stage aaron and me decided that automatically attempting to call a generic

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-18 Thread sympy
Comment #14 on issue 2624 by ness...@googlemail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 Already there. (last line of test_meijerint in integrals/tests/test_meijerint.py) -- You received this message because you are subscribed

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-17 Thread sympy
Updates: Labels: NeedsReview Comment #12 on issue 2624 by ness...@googlemail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 as reported before, this works in gsoc-3 which is now up for review: https://github.com/sympy/sympy/pull/543

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-17 Thread sympy
Comment #13 on issue 2624 by asmeurer: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 By the way, also add a test for the integral from that paper. -- You received this message because you are subscribed to the Google Groups sympy-issues group

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-06 Thread sympy
Comment #10 on issue 2624 by ness...@googlemail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 The ideal solution would be to figure out ways to make it simpler in the algorithm itself. I agree, but I don't see how to. integrate(exp(-(x-1

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-06 Thread sympy
Comment #11 on issue 2624 by ness...@googlemail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 I should mention that, of course, we can do all the steps of the paper by hand: In [6]: mellin_transform((2-x)**alpha*Heaviside(2-x), x, s) Out

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-05 Thread sympy
Comment #4 on issue 2624 by ness...@googlemail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 As I already told Matthew, integrals code does not do any simplification. Perhaps this should be changed (maybe calling cancel if an integral

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-05 Thread sympy
Comment #5 on issue 2624 by asmeurer: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 I'm not sure actually. Calling simplify() or even cancel() can make integrate() slow. On the other hand, it seems like most of the time there is a very simple

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-05 Thread sympy
Comment #8 on issue 2624 by matt...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 I can help review it. Yes, it's EuroSciPy. -- You received this message because you are subscribed to the Google Groups sympy-issues group. To post

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-05 Thread sympy
Comment #9 on issue 2624 by asmeurer: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 By the way, that would indeed be very cool if we could do the integral from that paper. The author wants to know how Mathematica does the integral

Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-04 Thread sympy
Status: New Owner: Labels: Type-Defect Priority-Medium New issue 2624 by alex.ebe...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 Integration of a basic Gaussian works: In [9]: integrate(exp(-x**2), (x,-oo,+oo)) Out[9

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-04 Thread sympy
Updates: Status: Started Owner: ness...@googlemail.com Labels: Integration Comment #1 on issue 2624 by matt...@gmail.com: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 This works in one of our development branches (https

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-04 Thread sympy
Comment #2 on issue 2624 by asmeurer: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 Yes, Tom is working with Matthew to make sure that all the common integrals from statistics work. This will likely be in the next release, unless someone wants

Re: Issue 2624 in sympy: Sympy 0.7.1 can't integrate Gaussians

2011-08-04 Thread sympy
Comment #3 on issue 2624 by asmeurer: Sympy 0.7.1 can't integrate Gaussians http://code.google.com/p/sympy/issues/detail?id=2624 And another issue of poor simplification: In [2]: integrate(exp(-x**2 + 2*x - 1), (x, -oo, oo)) Out[2]: ⎽⎽⎽ ⎽⎽⎽ ╲╱ π ⋅(-erf(1) + 1) ╲╱ π ⋅(erf