Changeset 206e158 in git for kernel/rmodulo2m.cc

Timestamp:

May 11, 2007, 12:48:05 PM (17 years ago)

Author:

Oliver Wienand <wienand@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

d15996cd44ce997d3360fac629f4062adb1c4836

Parents:

3fd4df896525da08d34f33e88e6239994fa4d0e6

Message:

structs.h, numbers.*, rmodulo*:
new method nComp
nIntDiv(0, a) = module / a in rmodulo

ringgb.*:
adapted for more generic rings

ring.h:
rField_is_Domain new

k*:
adapted for gbs over Z/m


git-svn-id: file:///usr/local/Singular/svn/trunk@10034 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• kernel/rmodulo2m.cc (modified) (4 diffs)

kernel/rmodulo2m.cc

@@ -2 +2 @@
 *  Computer Algebra System SINGULAR     *
 ****************************************/
-/* $Id: rmodulo2m.cc,v 1.8 2007-05-10 08:12:43 wienand Exp $ */
+/* $Id: rmodulo2m.cc,v 1.9 2007-05-11 10:48:05 wienand Exp $ */
 /*
 * ABSTRACT: numbers modulo 2^m
@@ -70 +70 @@
     res++;
   }
-  if ((NATNUMBER) b % 2 == 0)
-  {
-    return (number) ((1L << res));// * (NATNUMBER) a);  // (2**res)*a    a ist Einheit
-  }
-  else
-  {
+//  if ((NATNUMBER) b % 2 == 0)
+//  {
+//    return (number) ((1L << res));// * (NATNUMBER) a);  // (2**res)*a    a ist Einheit
+//  }
+//  else
+//  {
     return (number) ((1L << res));// * (NATNUMBER) b);  // (2**res)*b    b ist Einheit
-  }
+//  }
 }
 
@@ -163 +163 @@
 }
   return ((NATNUMBER) b % 2 == 1);
+}
+
+int nr2mComp(number as, number bs)
+{
+  NATNUMBER a = (NATNUMBER) as;
+  NATNUMBER b = (NATNUMBER) bs;
+  assume(a != 0 && b != 0);
+  while (a % 2 == 0 && b % 2 == 0)
+  {
+    a = a / 2;
+    b = b / 2;
+  }
+  if (a % 2 == 0)
+  {
+    return -1;
+  }
+  else
+  {
+    if (b % 2 == 1)
+    {
+      return 0;
+    }
+    else
+    {
+      return 1;
+    }
+  }
 }
 
@@ -271 +298 @@
   if ((NATNUMBER)a==0)
   {
-    return (number) 0;
-  }
-  else
-  {
+    if ((NATNUMBER)b==0)
+      return (number) 1;
+    return (number) (nr2mModul / (NATNUMBER) b);
+  }
+  else
+  {
+    if ((NATNUMBER)b==0)
+      return (number) 0;
     return (number) ((NATNUMBER) a / (NATNUMBER) b);
   }