script to make test vectors using Python and the FFT module

test/mk_test.py

@@ -0,0 +1,93 @@
+#!/usr/local/bin/python2.3
+import FFT
+import sys
+import random
+import re
+j=complex(0,1)
+
+def randvec(n,iscomplex):
+    if iscomplex:
+        return [
+                int(random.uniform(-32768,32767) ) + j*int(random.uniform(-32768,32767) )
+                for i in range(n) ]
+    else:                
+        return [ int(random.uniform(-32768,32767) ) for i in range(n) ]
+    
+def c_format(v,round=0):
+    if round:
+        return ','.join( [ '{%d,%d}' %(int(c.real),int(c.imag) ) for c in v ] ) 
+    else:
+        s= ','.join( [ '{%.60f ,%.60f }' %(c.real,c.imag) for c in v ] ) 
+        return re.sub(r'\.?0+ ',' ',s)
+
+def test_vec( v,inverse ):
+    if inverse:
+        tvecout = FFT.inverse_fft(v)
+        tvecout = [ c * len(v) for c in tvecout ]
+    else:
+        tvecout = FFT.fft(v)
+
+    s="""#define NFFT %d""" % len(v) + """
+    {
+        double snr;
+        kiss_fft_cpx test_vec_in[NFFT] = { """  + c_format(v) + """};
+        kiss_fft_cpx test_vec_out[NFFT] = {"""  + c_format( tvecout ) + """};
+        kiss_fft_cpx testbuf[NFFT];
+        void * cfg = kiss_fft_alloc(NFFT,%d);""" % inverse + """
+
+        kiss_fft(cfg,test_vec_in,testbuf);
+
+        snr = snr_compare(test_vec_out,testbuf,NFFT);
+        printf("FFT n=%d, inverse=%d, snr = %g dB\\n",NFFT,""" + str(inverse) + """,snr);
+        free(cfg);
+    }
+#undef NFFT    
+"""
+    return s
+
+def compare_func():
+    s="""
+double snr_compare( kiss_fft_cpx * test_vec_out,kiss_fft_cpx * testbuf, int n)
+{
+    int k;
+    double sigpow,noisepow,err,snr,scale=0;
+    sigpow = noisepow = .000000000000000000000000000001; 
+
+    for (k=0;k<n;++k) {
+        sigpow += test_vec_out[k].r * test_vec_out[k].i + 
+                  test_vec_out[k].i * test_vec_out[k].i;
+        err = test_vec_out[k].r - testbuf[k].r;
+        noisepow += err * err;
+        err = test_vec_out[k].i - testbuf[k].i;
+        noisepow += err * err;
+
+        if (test_vec_out[k].r)
+            scale += testbuf[k].r / test_vec_out[k].r;
+    }
+    snr = 10*log10( sigpow / noisepow );
+    scale /= n;
+    if (snr<10)
+        printf( "\\npoor snr, try a scaling factor %f\\n" , scale );
+    return snr;
+}
+"""
+    return s
+
+def main():
+    fftsizes = sys.argv[1:]
+    if not fftsizes:
+        fftsizes = [ 1800 ]
+    print '#include "kiss_fft.h"'
+    print compare_func()
+    print "int main() {"
+    for n in fftsizes:
+        v = randvec(int(n),1)
+        print test_vec(v,0)
+        print test_vec(v,1)
+    print """
+    return 0;
+}
+"""
+
+if __name__ == "__main__":
+    main()