Changeset 803956 in git for factory/facFqSquarefree.cc

Timestamp:

Apr 7, 2013, 2:20:04 AM (10 years ago)

Author:

Martin Lee <martinlee84@…>

Branches:

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

Children:

919cae9250ad682976bdd4a2ecfe501d48b672dd

Parents:

52cccfd3872fe7f123040534ad2fdbde32e83b75

git-author:

Martin Lee <martinlee84@web.de>2013-04-07 02:20:04+02:00

git-committer:

Martin Lee <martinlee84@web.de>2013-04-08 14:42:32+02:00

Message:

fix: wrong computation of pth root due to int overflow

File:

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

factory/facFqSquarefree.cc

@@ -24 +24 @@
 #include "facFqSquarefree.h"
 
+#ifdef HAVE_NTL
+#include "NTLconvert.h"
+#endif
+
 static inline
 CanonicalForm
@@ -43 +47 @@
   }
 }
+
+#ifdef HAVE_NTL
+CanonicalForm
+pthRoot (const CanonicalForm & F, const ZZ& q, const Variable& alpha)
+{
+  CanonicalForm A= F;
+  int p= getCharacteristic ();
+  if (A.inCoeffDomain())
+  {
+    zz_p::init (p);
+    zz_pX NTLMipo= convertFacCF2NTLzzpX (getMipo (alpha));
+    zz_pE::init (NTLMipo);
+    zz_pX NTLA= convertFacCF2NTLzzpX (A);
+    zz_pE NTLA2= to_zz_pE (NTLA);
+    power (NTLA2, NTLA2, q/p);
+    A= convertNTLzzpE2CF (NTLA2, alpha);
+    return A;
+  }
+  else
+  {
+    CanonicalForm buf= 0;
+    for (CFIterator i= A; i.hasTerms(); i++)
+      buf= buf + power(A.mvar(), i.exp()/p)*pthRoot (i.coeff(), q, alpha);
+    return buf;
+  }
+}
+#endif
 
 CanonicalForm
@@ -157 +188 @@
     return CFFList (CFFactor (F/Lc(F), 1));
 
-  CanonicalForm buffer= pthRoot (A, ipower (p, k));
+  CanonicalForm buffer;
+#ifdef HAVE_NTL
+  if (alpha.level() == 1)
+#endif
+    buffer= pthRoot (A, ipower (p, k));
+#ifdef HAVE_NTL
+  else
+  {
+    ZZ q;
+    power (q, p, k);
+    buffer= pthRoot (A, q, alpha);
+  }
+#endif
 
   tmp1= squarefreeFactorization (buffer, alpha);