diff ext/kissfft/test/fastfir.py @ 409:1f1999b0f577

Bring in kissfft into this repo (formerly a subrepo, but the remote is not responding)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ext/kissfft/test/fastfir.py	Tue Jul 21 07:34:15 2015 +0100
@@ -0,0 +1,102 @@
+#!/usr/bin/env python
+
+from Numeric import *
+from FFT import *
+
+def make_random(len):
+    import random
+    res=[]
+    for i in range(int(len)):
+        r=random.uniform(-1,1)
+        i=random.uniform(-1,1)
+        res.append( complex(r,i) )
+    return res
+
+def slowfilter(sig,h):
+    translen = len(h)-1
+    return convolve(sig,h)[translen:-translen]
+
+def nextpow2(x):
+    return 2 ** math.ceil(math.log(x)/math.log(2))
+
+def fastfilter(sig,h,nfft=None):
+    if nfft is None:
+        nfft = int( nextpow2( 2*len(h) ) )
+    H = fft( h , nfft )
+    scraplen = len(h)-1
+    keeplen = nfft-scraplen
+    res=[]
+    isdone = 0
+    lastidx = nfft
+    idx0 = 0
+    while not isdone:
+        idx1 = idx0 + nfft
+        if idx1 >= len(sig):
+            idx1 = len(sig)
+            lastidx = idx1-idx0
+            if lastidx <= scraplen:
+                break
+            isdone = 1
+        Fss = fft(sig[idx0:idx1],nfft)
+        fm = Fss * H
+        m = inverse_fft(fm)
+        res.append( m[scraplen:lastidx] )
+        idx0 += keeplen
+    return concatenate( res )
+
+def main():
+    import sys
+    from getopt import getopt
+    opts,args = getopt(sys.argv[1:],'rn:l:')
+    opts=dict(opts)
+
+    siglen = int(opts.get('-l',1e4 ) )
+    hlen =50 
+ 
+    nfft = int(opts.get('-n',128) )
+    usereal = opts.has_key('-r')
+
+    print 'nfft=%d'%nfft
+    # make a signal
+    sig = make_random( siglen )
+    # make an impulse response
+    h = make_random( hlen )
+    #h=[1]*2+[0]*3
+    if usereal:
+        sig=[c.real for c in sig]
+        h=[c.real for c in h]
+
+    # perform MAC filtering
+    yslow = slowfilter(sig,h)
+    #print '<YSLOW>',yslow,'</YSLOW>'
+    #yfast = fastfilter(sig,h,nfft)
+    yfast = utilfastfilter(sig,h,nfft,usereal)
+    #print yfast
+    print 'len(yslow)=%d'%len(yslow)
+    print 'len(yfast)=%d'%len(yfast)
+    diff = yslow-yfast
+    snr = 10*log10( abs( vdot(yslow,yslow) / vdot(diff,diff) ) )
+    print 'snr=%s' % snr
+    if snr < 10.0:
+        print 'h=',h
+        print 'sig=',sig[:5],'...'
+        print 'yslow=',yslow[:5],'...'
+        print 'yfast=',yfast[:5],'...'
+
+def utilfastfilter(sig,h,nfft,usereal):
+    import compfft
+    import os
+    open( 'sig.dat','w').write( compfft.dopack(sig,'f',not usereal) )
+    open( 'h.dat','w').write( compfft.dopack(h,'f',not usereal) )
+    if usereal: 
+        util = './fastconvr' 
+    else:
+        util = './fastconv'
+    cmd = 'time %s -n %d -i sig.dat -h h.dat -o out.dat' % (util, nfft)
+    print cmd
+    ec  = os.system(cmd)
+    print 'exited->',ec
+    return compfft.dounpack(open('out.dat').read(),'f',not usereal)
+
+if __name__ == "__main__":
+    main()