Changeset 55608a7 in git

Timestamp:

May 19, 2011, 3:44:04 PM (12 years ago)

Author:

Martin Lee <martinlee84@…>

Branches:

(u'spielwiese', '0d6b7fcd9813a1ca1ed4220cfa2b104b97a0a003')

Children:

20721265ad8d95578883f26318500530eacc7f96

Parents:

b4f7ebdb67074ac439d1df267fda83171f69d3b8

Message:

added new functionality to map between extension


git-svn-id: file:///usr/local/Singular/svn/trunk@14232 2c84dea3-7e68-4137-9b89-c4e89433aadc

Location:

factory

Files:

• cf_map_ext.cc (modified) (5 diffs)
• cf_map_ext.h (modified) (3 diffs)

factory/cf_map_ext.cc

@@ -38 +38 @@
 
 /// helper function
-static inline
 int findItem (const CFList& list, const CanonicalForm& item)
 {
@@ -51 +50 @@
 
 /// helper function
-static inline
 CanonicalForm getItem (const CFList& list, const int& pos)
 {
@@ -115 +113 @@
     if (pos == 0)
     {
-      alpha_power= buf*power (alpha, counter);
+      alpha_power= power (alpha, counter);
       dest.append (alpha_power);
     }
@@ -138 +136 @@
 CanonicalForm GF2FalphaHelper (const CanonicalForm& F, const Variable& alpha)
 {
+  if (F.isZero())
+    return 0;
   int exp;
   CanonicalForm result= 0;
@@ -385 +385 @@
 
 CanonicalForm
+map (const CanonicalForm& primElem, const Variable& alpha,
+     const CanonicalForm& F, const Variable& beta)
+{
+  CanonicalForm G= F;
+  int order= 0;
+  while (!G.isOne())
+  {
+    G /= primElem;
+    order++;
+  }
+  int p= getCharacteristic ();
+  zz_p::init (p);
+  zz_pX NTL_mipo= convertFacCF2NTLzzpX (getMipo (beta)); 
+  zz_pE::init (NTL_mipo);
+  zz_pEX NTL_alpha_mipo= convertFacCF2NTLzz_pEX (getMipo(alpha), NTL_mipo);
+  zz_pE NTLBeta= to_zz_pE (convertFacCF2NTLzzpX (beta));
+  vec_zz_pE roots= FindRoots (NTL_alpha_mipo);
+  long ind;
+  for (long i= 0; i < roots.length(); i++)
+  {
+    if (power (roots [i], order)== NTLBeta)
+    {
+      ind= i;
+      break;
+    }
+  }
+  return (convertNTLzzpE2CF (roots[ind], beta));
+}
+
+CanonicalForm
 findMinPoly (const CanonicalForm& F, const Variable& alpha)
 {

factory/cf_map_ext.h

@@ -20 +20 @@
 
 #include <config.h>
+
+int findItem (const CFList& list, const CanonicalForm& item);
+
+CanonicalForm getItem (const CFList& list, const int& pos);
 
 CanonicalForm GFMapUp (const CanonicalForm & F, int k);
@@ -46 +50 @@
 CanonicalForm Falpha2GFRep (const CanonicalForm& F);
 
-#ifdef HAVE_NTL
+/// map from \f$ F_p(\alpha) \f$ to \f$ F_p(\beta) \f$ such that 
+/// \f$ F\in\F_p(\alpha) \f$ is mapped onto \f$ \beta \f$
+///
+/// @return @a map returns the image of @a primElem such that the above 
+/// described properties hold
+CanonicalForm
+map (const CanonicalForm& primElem,///< [in] primitive element of 
+                                   ///< \f$ F_p (\alpha) \f$
+     const Variable& alpha,        ///< [in] algebraic variable
+     const CanonicalForm& F,       ///< [in] an element of \f$ F_p (\alpha) \f$,
+                                   ///< whose minimal polynomial defines a field
+                                   ///< extension of \f$ F_p \f$ of degree
+                                   ///< \f$ \[F_p (\alpha):F_p\] \f$
+     const Variable& beta          ///< [in] algebraic variable, root of \a F's
+                                   ///< minimal polynomial
+    );
+
 /// compute minimal polynomial of \f$ F\in\F_p(\alpha)\backslash\F_p \f$ via NTL
 ///
@@ -55 +75 @@
              const Variable& alpha   ///< [in] algebraic variable
             );
+
 #endif
-#endif