`fourier(sym(2), x, w)` gives `0` instead of dirac

gnu-octave / symbolic

A Symbolic Package for Octave using SymPy

https://octave.sourceforge.io/symbolic/

GNU General Public License v3.0

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`fourier(sym(2), x, w)` gives `0` instead of dirac #251

Open cbm755 opened 9 years ago

maprieto commented 9 years ago

This is issue is confirmed in Sympy. Also other Fourier series are not computed correctly:

import sympy as sp
from sympy.abc import x, w
sp.fourier_transform(2, x, w)
sp.fourier_transform(sp.cos(x), x, w)
sp.fourier_transform(sp.sin(x), x, w)

So, it could be labelled as upstream (see https://github.com/sympy/sympy/issues/2803)

cbm755 commented 9 years ago

Possibly related: sympy does something stupid where it assumes the first choice of every piecewise result is the answer (!) This is one reason so many transforms give 0. I've been meaning to look into fixing that.

Thanks for the link.

cbm755 commented 8 years ago

@maprieto has added a work around for us, but it still needs to be fixed in upstream sympy