ippsFFTInitAlloc_C_32f : for initalising the twidle factors and FFT specification.
(ippsFFTInitAlloc_C_32f(&twiddles.spec, order, IPP_FFT_DIV_INV_BY_N, ippAlgHintAccurate);)
ippsFFTFwd_CToC_32f : computing the FFT.
I am attaching the Input and output of FFT function result for 32 bit and 64 bit version.
Is there any way to look at the twiddle factor genrated by ippsFFTInitAlloc_C_32f
Is the difference in FFT output for 64 and 32 bit is a known thing or there something wrong.Kindly let me know the potentail things to look-in.
I looked the RealOut results you received.
Here two first numbers from RealOut files
32 bit 64 bit
As you can see the difference in the results to be within the accuracy of floating-point ( which isFLT_EPSILON - see float.h )which you use.