[SCM] an open source computer algebra system branch, cleanedupstream, updated. 6125e540ca6d66c307958938a9d53b245507c323

[Bernhard R. Link]

The following commit has been merged in the cleanedupstream branch:
commit b39974a35e993c82df3b74afc01fb3f2fe8ddd2e
Author: Martin Lee <martinlee84 at web.de>
Date:   Mon Jan 9 13:59:20 2012 +0100

    chg: added functions to compute better lifting precisions
         based on the shape of the Newton polygon

diff --git a/factory/facFqBivar.cc b/factory/facFqBivar.cc
index 47d62c5..5eb5539 100644
--- a/factory/facFqBivar.cc
+++ b/factory/facFqBivar.cc
@@ -777,6 +777,61 @@ extEarlyFactorDetection (CanonicalForm& F, CFList& factors,
   return result;
 }
 
+int*
+getCombinations (int * rightSide, int sizeOfRightSide, int& sizeOfOutput,
+                 int degreeLC)
+{
+  Variable x= Variable (1);
+  int p= getCharacteristic();
+  int d= getGFDegree();
+  char cGFName= gf_name;
+  setCharacteristic(0);
+  CanonicalForm buf= 1;
+  for (int i= 0; i < sizeOfRightSide; i++)
+    buf *= (power (x, rightSide [i]) + 1);
+
+  int j= 0;
+  for (CFIterator i= buf; i.hasTerms(); i++, j++)
+  {
+    if (i.exp() < degreeLC)
+    {
+      j++;
+      break;
+    }
+  }
+
+  ASSERT ( j > 1, "j > 1 expected" );
+
+  int* result = new int  [j - 1];
+  sizeOfOutput= j - 1;
+
+  int i= 0;
+  for (CFIterator m = buf; i < j - 1; i++, m++)
+    result [i]= m.exp();
+
+  if (d > 1)
+    setCharacteristic (p, d, cGFName);
+  else
+    setCharacteristic (p);
+  return result;
+}
+
+int *
+getLiftPrecisions (const CanonicalForm& F, int& sizeOfOutput, int degreeLC)
+{
+  int sizeOfNewtonPoly;
+  int ** newtonPolyg= newtonPolygon (F, sizeOfNewtonPoly);
+  int sizeOfRightSide;
+  int * rightSide= getRightSide(newtonPolyg, sizeOfNewtonPoly, sizeOfRightSide);
+  int * result= getCombinations(rightSide, sizeOfRightSide, sizeOfOutput,
+                                degreeLC);
+  delete [] rightSide;
+  for (int i= 0; i < sizeOfNewtonPoly; i++)
+    delete [] newtonPolyg[i];
+  delete [] newtonPolyg;
+  return result;
+}
+
 CFList
 henselLiftAndEarly (CanonicalForm& A, bool& earlySuccess, CFList&
                     earlyFactors, DegreePattern& degs, int& liftBound,
diff --git a/factory/facFqBivar.h b/factory/facFqBivar.h
index 7933a6b..4a7f63b 100644
--- a/factory/facFqBivar.h
+++ b/factory/facFqBivar.h
@@ -661,6 +661,18 @@ Variable chooseExtension (
                       int k                   ///< [in] some int
                          );
 
+/// compute lifting precisions from the shape of the Newton polygon of F
+///
+/// @return @a getLiftPrecisions returns lifting precisions computed from the
+/// shape of the Newton polygon of F
+int *
+getLiftPrecisions (const CanonicalForm& F, ///< [in] a bivariate poly
+                   int& sizeOfOutput,      ///< [in,out] size of the output
+                   int degreeLC            ///< [in] degree of the leading coeff
+                                           ///< [in] of F wrt. Variable (1)
+                  );
+
+
 /// detects factors of @a F at stage @a deg of Hensel lifting.
 /// No combinations of more than one factor are tested. Lift bound and possible
 /// degree pattern are updated.

-- 
an open source computer algebra system