[MN-dev] [mndiff]: r183 - trunk/noe/galois.c

[michael]

Author: michael
Date: Tue Jun 29 22:15:33 2010
New Revision: 183

Log:
Improve speed of prodPoly()

Modified:
   trunk/noe/galois.c

Modified: trunk/noe/galois.c
==============================================================================
--- trunk/noe/galois.c	Thu Jun 24 15:01:06 2010	(r182)
+++ trunk/noe/galois.c	Tue Jun 29 22:15:33 2010	(r183)
@@ -98,7 +98,7 @@ void EXT(prodPoly)(GFF4Element *dst, GFF
             dst[i]= reduce(acc);
         }
     }else{
-        const int logSize= noe_log2(NOE_MIN(order, 1<<(SHIFT-1)))+1;
+        const int logSize= noe_log2(NOE_MIN(order-1, 1<<(SHIFT-1)))+1;
         const int size= 1<<logSize;
         GFF4Element temp[2][size]; //FIXME is this fast?
         const GFF4Element scale= inv(size);
@@ -117,6 +117,11 @@ void EXT(prodPoly)(GFF4Element *dst, GFF
         }
 
         EXT(igfft)(temp[0], temp[0], logSize);
+        if(size == order){
+            temp[0][order]= diff(temp[0][0], prod(src1[0], src2[0]));
+            temp[0][    0]= diff(temp[0][0], temp[0][order]);
+        }
+
         memcpy(dst, temp[0], sizeof(GFF4Element)*(order+1));
     }
 }