Chris@366: #!/usr/bin/env python
Chris@366: 
Chris@366: # use FFTPACK as a baseline
Chris@366: import FFT
Chris@366: from Numeric import *
Chris@366: import math
Chris@366: import random
Chris@366: import sys
Chris@366: import struct
Chris@366: import fft
Chris@366: 
Chris@366: pi=math.pi
Chris@366: e=math.e
Chris@366: j=complex(0,1)
Chris@366: lims=(-32768,32767)
Chris@366: 
Chris@366: def randbuf(n,cpx=1):
Chris@366:     res = array( [ random.uniform( lims[0],lims[1] ) for i in range(n) ] )
Chris@366:     if cpx:
Chris@366:         res = res + j*randbuf(n,0)
Chris@366:     return res
Chris@366: 
Chris@366: def main():
Chris@366:     from getopt import getopt
Chris@366:     import popen2
Chris@366:     opts,args = getopt( sys.argv[1:],'u:n:Rt:' )
Chris@366:     opts=dict(opts)
Chris@366:     exitcode=0
Chris@366: 
Chris@366:     util = opts.get('-u','./kf_float')
Chris@366: 
Chris@366:     try:
Chris@366:         dims = [ int(d) for d in opts['-n'].split(',')]
Chris@366:         cpx = opts.get('-R') is None
Chris@366:         fmt=opts.get('-t','f')
Chris@366:     except KeyError:
Chris@366:         sys.stderr.write("""
Chris@366:         usage: compfft.py 
Chris@366:         -n d1[,d2,d3...]  : FFT dimension(s)
Chris@366:         -u utilname : see sample_code/fftutil.c, default = ./kf_float
Chris@366:         -R : real-optimized version\n""")
Chris@366:         sys.exit(1)
Chris@366: 
Chris@366:     x = fft.make_random( dims )
Chris@366: 
Chris@366:     cmd = '%s -n %s ' % ( util, ','.join([ str(d) for d in dims]) )
Chris@366:     if cpx:
Chris@366:         xout = FFT.fftnd(x)
Chris@366:         xout = reshape(xout,(size(xout),))
Chris@366:     else:
Chris@366:         cmd += '-R '
Chris@366:         xout = FFT.real_fft(x)
Chris@366: 
Chris@366:     proc = popen2.Popen3( cmd , bufsize=len(x) )
Chris@366: 
Chris@366:     proc.tochild.write( dopack( x , fmt ,cpx ) )
Chris@366:     proc.tochild.close()
Chris@366:     xoutcomp = dounpack( proc.fromchild.read( ) , fmt ,1 )
Chris@366:     #xoutcomp = reshape( xoutcomp , dims )
Chris@366: 
Chris@366:     sig = xout * conjugate(xout)
Chris@366:     sigpow = sum( sig )
Chris@366: 
Chris@366:     diff = xout-xoutcomp
Chris@366:     noisepow = sum( diff * conjugate(diff) )
Chris@366: 
Chris@366:     snr = 10 * math.log10(abs( sigpow / noisepow ) )
Chris@366:     if snr<100:
Chris@366:         print xout
Chris@366:         print xoutcomp
Chris@366:         exitcode=1
Chris@366:     print 'NFFT=%s,SNR = %f dB' % (str(dims),snr)
Chris@366:     sys.exit(exitcode)
Chris@366: 
Chris@366: def dopack(x,fmt,cpx):
Chris@366:     x = reshape( x, ( size(x),) )
Chris@366:     if cpx:
Chris@366:         s = ''.join( [ struct.pack('ff',c.real,c.imag) for c in x ] )
Chris@366:     else:
Chris@366:         s = ''.join( [ struct.pack('f',c) for c in x ] )
Chris@366:     return s 
Chris@366: 
Chris@366: def dounpack(x,fmt,cpx):
Chris@366:     uf = fmt * ( len(x) / 4 )
Chris@366:     s = struct.unpack(uf,x)
Chris@366:     if cpx:
Chris@366:         return array(s[::2]) + array( s[1::2] )*j
Chris@366:     else:    
Chris@366:         return array(s )
Chris@366: 
Chris@366: if __name__ == "__main__":
Chris@366:     main()