the normalization is not a problem. Dear Suominen, than you for the try, but this was not the point.

Sympy uses the unitary, ordinary-frequency inverse Fourier transform and there should be not 1/2pi. The problem is much deeper; that final result (without the normalization) is different from the theoretical result when the assumption Re[lambda]>0 or Re[lambda]<0 and t>0 or t<0 are used. Hope for help. On Tuesday, April 10, 2018 at 1:44:29 PM UTC+2, Kalevi Suominen wrote: > > There are two common definitions of inverse Fourier transform depending on > how the frequency variable is interpreted. (See > https://en.wikipedia.org/wiki/Fourier_transform#Other_conventions) The > stackexchange post is using the angular frequency ω that differs by the > factor 2π from frequency variable assumed by SymPy. The transforms are also > differently normalized. That may explain the differing results. > > Kalevi Suominen > > On Tuesday, April 10, 2018 at 9:16:57 AM UTC+3, Janko Slavič wrote: >> >> I am trying to replicate this: >> >> https://math.stackexchange.com/questions/2280196/inverse-fourier-transform-of-a-partial-fraction-decomposition >> with sympy. >> >> With Mathematica I get just the same behavior as the above theory >> suggest. >> >> With sympy I it looks wrong. At t<0, I get the result close to the >> correct one for t>0. (I was not able to include all the assumptions in >> sympy). >> >> Here is the sympy code: >> >> import sympy as sym >> sym.init_printing() >> ω = sym.symbols('omega', real=True, positive=True) >> R, λ = sym.symbols('R, lambda', complex=True) >> t = sym.symbols('t', real=True, positive=True) >> α = R/(sym.I*ω-λ)+sym.conjugate(R)/(sym.I*ω-sym.conjugate(λ)) >> α >> sym.inverse_fourier_transform(α, ω, -t) >> >> >> and the Mathematica: >> >> a = InverseFourierTransform[ R/(I omega - lambda) + Conjugate[R]/(I >> omega - Conjugate[lambda]), omega, t, >> FourierParameters -> {1, -1}] >> Simplify[a, {Re[lambda] < 0, t > 0}] >> >> Is the sympy result really wrong? >> > -- 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 sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/ac10a06e-7070-427c-861f-f4590f3c4613%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.