closer

fft.py

@@ -23,12 +23,15 @@ def fft(f):
         Fm.extend( Fp )
 
     Fout = [ 0 ] * n
-    for k in range(n):
-        km = (k%m)
-        val = Fm[ km ]
+    for u in range(m):
+        scratch = Fm[u::m] # u to end in strides of m
+        for q1 in range(p):
+            k = q1*m + u  # indices to Fout above that became scratch
+            val = Fm[ u ]
             for q in range(1,p):
                 t = e ** ( j*2*pi*k*q/n )
-            val += Fm[ q*m + km ] * t
+                #Fout[ k ] += scratch[q] * t
+                val += Fm[ q*m + u ] * t
             Fout[ k ] = val
 
     return Fout