Changeset 02af91 in git for factory/ffops.cc

Timestamp:

Jun 18, 1996, 8:57:00 AM (27 years ago)

Author:

Rüdiger Stobbe <stobbe@…>

Branches:

(u'spielwiese', 'a719bcf0b8dbc648b128303a49777a094b57592c')

Children:

cfa45ec3cccf336939c446d85de2dca6283593b1

Parents:

35930b6cf4435468b76d893cb0f2be0e692720cf

Message:

"Now the functionality to handle prime numbers that are bigger than 2^15.
This results in various changes and some new functions.
"


git-svn-id: file:///usr/local/Singular/svn/trunk@21 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• factory/ffops.cc (modified) (2 diffs)

factory/ffops.cc

@@ -1 +1 @@
 // emacs edit mode for this file is -*- C++ -*-
-// $Id: ffops.cc,v 1.0 1996-05-17 10:59:46 stobbe Exp $
+// $Id: ffops.cc,v 1.1 1996-06-18 06:57:00 stobbe Exp $
 
 /*
 $Log: not supported by cvs2svn $
+Revision 1.0  1996/05/17 10:59:46  stobbe
+Initial revision
+
 */
 
@@ -12 +15 @@
 int ff_prime = 31991;
 int ff_halfprime = 31991 / 2;
+bool ff_big = false;
 short * ff_invtab = new short [31991];
 
 void ff_setprime ( const int p )
 {
-  ff_prime = p;
-  ff_halfprime = ff_prime / 2;
-  for ( int i = 0; i < ff_prime; i++ ) ff_invtab[i] = 0;
+    ff_prime = p;
+    ff_halfprime = ff_prime / 2;
+    if ( ! ff_big )
+        for ( int i = 0; i < ff_prime; i++ ) ff_invtab[i] = 0;
 }
 
 int ff_newinv ( const int a )
 {
-  int u, r0 = a, r1 = ff_prime, q0 = 1, q1 = 0;
-  while ( ( r0 > 0 ) && ( r1 > 0 ) ) {
-    u = r0 / r1;
-    r0 = r0 % r1;
-    q0 = u*q1 + q0;
-    if ( r0 > 0 ) {
-      u = r1 / r0;
-      r1 = r1 % r0;
-      q1 = u*q0 + q1;
+    int u, r0 = a, r1 = ff_prime, q0 = 1, q1 = 0;
+    while ( ( r0 > 0 ) && ( r1 > 0 ) ) {
+        u = r0 / r1;
+        r0 = r0 % r1;
+        q0 = u*q1 + q0;
+        if ( r0 > 0 ) {
+            u = r1 / r0;
+            r1 = r1 % r0;
+            q1 = u*q0 + q1;
+        }
     }
-  }
-  if ( r0 == 0 )
-    return (ff_invtab[a] = -q1);
-  else
-    return (ff_invtab[a] = q0);
+    if ( r0 == 0 )
+        return (ff_invtab[a] = -q1);
+    else
+        return (ff_invtab[a] = q0);
 }
+
+int ff_biginv ( const int a )
+{
+    int u, r0 = a, r1 = ff_prime, q0 = 1, q1 = 0;
+    while ( ( r0 > 0 ) && ( r1 > 0 ) ) {
+        u = r0 / r1;
+        r0 = r0 % r1;
+        q0 = u*q1 + q0;
+        if ( r0 > 0 ) {
+            u = r1 / r0;
+            r1 = r1 % r0;
+            q1 = u*q0 + q1;
+        }
+    }
+    if ( r0 == 0 )
+        return -q1;
+    else
+        return q0;
+}