On Sun, Jan 17, 2021 at 6:50 AM S.Y. Lee <[email protected]> wrote: > > I have also seen that meijerg integration can give imprecise result for > convergence for some cases > https://github.com/sympy/sympy/issues/16242. > I'm not sure if this problem can be solved algorithmically, but if it can't I > think that we have other technical reason to have table lookups for > integrations.
The convergence conditions come from the general G-function convergence conditions. See https://docs.sympy.org/latest/modules/integrals/g-functions.html#the-g-function-integration-theorems. I don't know if they can be tightened. It might be possible to do so for certain special cases, but one would need to do a deep investigation of the theory. Perhaps it is possible, for instance, that in some cases a more specific type of special function than the G-function can be used that has tighter convergence conditions. Convergence conditions for table lookup integrals should be possible. The tricky part is finding a sufficiently general form of the integral to match against, for which you can compute a general tight convergence condition. Also, two asides: - The convergence conditions should also be simplified better. In the issue you have abs(arg(w) + pi/2) <= pi/2 which is equivalent to im(w) < 0. SymPy needs to be able to simplify conditions like these. - I don't know how well the manualintegrate module will scale to lots of table lookups. We might run into a wall, in which case, we may need to look into using RUBI again. Aaron Meurer > > On Saturday, January 16, 2021 at 1:45:37 PM UTC+9 [email protected] wrote: >> >> Yes, I've already started that, I'll keep you posted. >> >> On Sat, Jan 16, 2021 at 3:28 AM Aaron Meurer <[email protected]> wrote: >>> >>> The best place to start is to familiarize yourself with SymPy and the >>> codebase. The best way to do this is to start to make pull requests >>> fixing simple things. >>> >>> Aaron Meurer >>> >>> On Fri, Jan 15, 2021 at 2:05 PM cheshta babbar <[email protected]> wrote: >>> > >>> > Hi, >>> > >>> > I really like the idea and am up for taking it as a gsoc project. Could >>> > you help me with that? And tell me where to begin with. >>> > >>> > On Sat, 16 Jan, 2021, 01:59 [email protected], >>> > <[email protected]> wrote: >>> >> >>> >> For sure really helpful ! (in fact mandatory to switch from Matlab to >>> >> Python in my teaching department ...) >>> >> >>> >> Le jeudi 26 mars 2020 à 22:38:50 UTC+1, ondrej a écrit : >>> >>> >>> >>> Hi, >>> >>> >>> >>> Here is a great idea for a GSoC project: >>> >>> >>> >>> https://github.com/sympy/sympy/issues/2803#issuecomment-604697523 >>> >>> >>> >>> Would any student be interested? I know at least one user who couldn't >>> >>> use SymPy because of that. So fixing it would be very useful to a lot >>> >>> of people. The scope of the GSoC project could be to get SymPy working >>> >>> with Fourier transforms of many such functions including Piecewise and >>> >>> adding a nice page to SymPy's documentation with examples. >>> >>> >>> >>> I'll be happy to mentor such a project. >>> >>> >>> >>> Ondrej >>> >> >>> >> -- >>> >> 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 view this discussion on the web visit >>> >> https://groups.google.com/d/msgid/sympy/901658c5-1a5a-4c27-a3e7-140e93d383adn%40googlegroups.com. >>> > >>> > -- >>> > 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 view this discussion on the web visit >>> > https://groups.google.com/d/msgid/sympy/CAL63R55%2BdO5d3XTxGrvouxTGRFXNOR%3D1w4e3zJVDBJeXnnNbdQ%40mail.gmail.com. >>> >>> -- >>> 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 view this discussion on the web visit >>> https://groups.google.com/d/msgid/sympy/CAKgW%3D6JHsFRFP2JOWJ9jvLYiWga9hAuUJBQoUexRsbdvojJoVA%40mail.gmail.com. > > -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/58fc4e52-ce78-446a-827e-0ce113440f15n%40googlegroups.com. -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6K-NPob7penJfaJ%3D5dzRb3%3DLi_B7ndn-GiyHNnVe9HfeA%40mail.gmail.com.
