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gnudatalanguage / gdl

GDL - GNU Data Language
GNU General Public License v2.0
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All cases of FFT are now supported by fftw.cpp #1897

Closed GillesDuvert closed 2 weeks ago

GillesDuvert commented 3 weeks ago

All cases of FFT are now supported by fftw.cpp GDL FFTW now ONLY when FFTW library is present. (old slow GSL code removed)

GillesDuvert commented 3 weeks ago

hm thanks to test...

GillesDuvert commented 3 weeks ago

OK. But now we have a problem: According to FFT documentation: "If the CENTER keyword is also set, then only the dimension given by the DIMENSION keyword is shifted to the center. The other dimensions remain unshifted."

This is NOT WHAT IDL DOES. (but GDL does, now) Proof: plot,ABS(FFT(FINDGEN(100,10),dim=1,/cen)) if the 2nd dimension is not shifted (as per the documentation) then the centered peaks should be in linear increasing order. This is true for GDL, but in IDL the peaks have been clearly shifted on the x-axis.

Bug report to IDL? Or reproduce this "feature" in GDL?

GillesDuvert commented 2 weeks ago

see #1898 . Our functionality did not change. good.