Changeset 15a879 in git for factory/facFqFactorize.cc

Timestamp:

Aug 27, 2012, 2:53:30 PM (11 years ago)

Author:

Martin Lee <martinlee84@…>

Branches:

(u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', 'a800fe4b3e9d37a38c5a10cc0ae9dfa0c15a4ee6')

Children:

ee4a7ded18ac9e58470a1628b76664aa441d3556

Parents:

e3cb321a536f5d1fea376ee2b01122921297faa8

git-author:

Martin Lee <martinlee84@web.de>2012-08-27 14:53:30+02:00

git-committer:

Martin Lee <martinlee84@web.de>2012-09-05 15:00:01+02:00

Message:

chg: pass to larger extension if over a small finite field

File:

• factory/facFqFactorize.cc (modified) (3 diffs)

factory/facFqFactorize.cc

@@ -705 +705 @@
 }
 
+#define CHAR_THRESHOLD 8
 CFList
 evalPoints (const CanonicalForm& F, CFList & eval, const Variable& alpha,
@@ -715 +716 @@
   GFRandom genGF;
   int p= getCharacteristic ();
+  if (p < CHAR_THRESHOLD && !GF && alpha.level() == 1) 
+  {
+    fail= true;
+    return CFList();
+  }
   double bound;
   if (alpha != x)
@@ -3280 +3286 @@
     bool extension= true;
     int p= getCharacteristic();
-    if (p*p < (1<<16)) // pass to GF if possible
+    if (p < 7)
+    {
+      if (p == 2)
+        setCharacteristic (getCharacteristic(), 6, 'Z');
+      else if (p == 3)
+        setCharacteristic (getCharacteristic(), 4, 'Z');
+      else if (p == 5)
+        setCharacteristic (getCharacteristic(), 3, 'Z');
+      ExtensionInfo info= ExtensionInfo (extension);
+      A= A.mapinto();
+      factors= multiFactorize (A, info);
+
+      CanonicalForm mipo= gf_mipo;
+      setCharacteristic (getCharacteristic());
+      Variable vBuf= rootOf (mipo.mapinto());
+      for (CFListIterator j= factors; j.hasItem(); j++)
+        j.getItem()= GF2FalphaRep (j.getItem(), vBuf);
+    }
+    else if (p >= 7 && p*p < (1<<16)) // pass to GF if possible
     {
       setCharacteristic (getCharacteristic(), 2, 'Z');