It is easy, but important. Otherwise, we're liable to forget about the bug.
Aaron Meurer On Mar 6, 2013, at 12:51 AM, G B <[email protected]> wrote: Thank for the confirmation, Aaron. I've got a deadline I'm struggling to meet, but I've got a list of issues and pull requests that I'll file when I get over the hump. It's probably trivial to do, but I'll have to figure it out the first time. Cheers-- Greg On Tuesday, March 5, 2013 4:07:24 PM UTC-8, Aaron Meurer wrote: > > Yes, this looks like a bug with the meijerg integration algorithm. > Please open an issue for it. > > For integrate(Heaviside(x-S(1)),(x,-1,2)), simplify() reduces this to > 1. So the "bug" here is that the appropriate simplification routine > should be called by integrate(). Open an issue for that one too. > > Aaron Meurer > > On Tue, Mar 5, 2013 at 11:11 AM, G B <[email protected] <javascript:>> > wrote: > > Just following up with more information-- I get the feeling this is > > different than Issue 1696. I get this behavior, all of which I find > > unexpected: > > > > In [1]: from sympy import * > > > > In [2]: from sympy.abc import x > > > > ## I would expect this to return S(1) without needing to evalf: > > In [3]: integrate(Heaviside(x),(x,-1,1)) > > Out[3]: Integral(Heaviside(x), (x, -1, 1)) > > > > In [4]: integrate(Heaviside(x),(x,-1,1)).n() > > Out[4]: 1.00000000000000 > > > > ## I would expect this to return Rational(1,2), strangely it doesn't > even > > return an > > ## unevaluated integral, it seems certain the answer here is precisely > zero. > > In [5]: integrate(Heaviside(x-Rational(1,2)),(x,-1,1)) > > Out[5]: 0 > > > > ## I would expect this to return S(1), what I get is far more > complicated: > > In [6]: integrate(Heaviside(x-S(1)),(x,-1,2)) > > Out[6]: -meijerg(((2, 1), ()), ((), (1, 0)), 1) + meijerg(((2, 1), ()), > ((), > > (1, 0)), 2) > > > > ## ...but evaluates correctly > > In [7]: integrate(Heaviside(x-S(1)),(x,-1,2)).n() > > Out[7]: 1.00000000000000 > > > > > > I get correct results spot evaluating Heaviside(x-Rational(1,2)) at > various > > points. Is the problem in integrate? > > > > > > On Tuesday, March 5, 2013 12:43:11 AM UTC-8, G B wrote: > >> > >> Maybe this is a symptom of: > >> http://code.google.com/p/sympy/issues/detail?id=1696 > >> > >> but this command: > >> integrate(Heaviside(x-0.2)-Heaviside(x-0.5),(x,0.,1.)) > >> > >> returns zero for me. > > > > -- > > You received this message because you are subscribed to the Google > Groups > > "sympy" group. > > To unsubscribe from this group and stop receiving emails from it, send > an > > email to [email protected] <javascript:>. > > To post to this group, send email to [email protected]<javascript:>. > > > Visit this group at http://groups.google.com/group/sympy?hl=en. > > For more options, visit https://groups.google.com/groups/opt_out. > > > > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy?hl=en. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
