Changeset 1577ebd in git for libpolys/polys

Timestamp:

Sep 27, 2011, 12:54:50 PM (13 years ago)

Author:

Hans Schoenemann <hannes@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

7f10dcde67f050fefbfeef12ce8d0108889fb6cc

Parents:

31c731745883c6d2ee7aba0e448c9320087d095a

git-author:

Hans Schoenemann <hannes@mathematik.uni-kl.de>2011-09-27 12:54:50+02:00

git-committer:

Mohamed Barakat <mohamed.barakat@rwth-aachen.de>2011-11-09 16:13:37+01:00

Message:

implented: ntGcd, ntLcm

File:

• libpolys/polys/ext_fields/transext.cc (modified) (2 diffs)

libpolys/polys/ext_fields/transext.cc

@@ -876 +876 @@
 {
   ntTest(a); ntTest(b);
-  /* TO BE IMPLEMENTED!
-     for the time, we simply return NULL, representing the number zero */
-  Print("// TO BE IMPLEMENTED: transext.cc:ntLcm\n");
+  fraction fb = (fraction)b;
+  if ((b==NULL)||(DEN(fb)==NULL)) return ntCopy(a,cf);
+#ifdef HAVE_FACTORY  
+  fraction fa = (fraction)a;
+  /* singclap_gcd destroys its arguments; we hence need copies: */
+  poly pa = p_Copy(NUM(fa), ntRing);
+  poly pb = p_Copy(DEN(fb), ntRing);
+  
+  /* Note that, over Q, singclap_gcd will remove the denominators in all
+     rational coefficients of pa and pb, before starting to compute
+     the gcd. Thus, we do not need to ensure that the coefficients of
+     pa and pb live in Z; they may well be elements of Q\Z. */
+  poly pGcd = singclap_gcd(pa, pb, cf->extRing);
+  if (p_IsConstant(pGcd, ntRing) &&
+      n_IsOne(p_GetCoeff(pGcd, ntRing), ntCoeffs))
+  { /* gcd = 1; return pa*pb*/
+    p_Delete(&pGcd,ntRing);
+    fraction result = (fraction)omAlloc0Bin(fractionObjectBin);
+    NUM(result) = pp_Mult_qq(NUM(fa),DEN(fb),ntRing);
+    return (number)result;
+  }
+  else
+  { /* return pa*pb/gcd */
+    p_Delete(&pGcd,ntRing);
+    poly newNum = singclap_pdivide(NUM(fa), pGcd, ntRing);
+    fraction result = (fraction)omAlloc0Bin(fractionObjectBin);
+    NUM(result) = p_Mult_q(p_Copy(DEN(fb),ntRing),newNum,ntRing);
+    return (number)result;
+  }
+#else
+  Print("// factory needed: transext.cc:ntLcm\n");
   return NULL;
+#endif /* HAVE_FACTORY */
+  return NULL;
 }
 
@@ -885 +915 @@
 {
   ntTest(a); ntTest(b);
-  /* TO BE IMPLEMENTED!
-     for the time, we simply return NULL, representing the number zero */
-  Print("// TO BE IMPLEMENTED: transext.cc:ntGcd\n");
+  if (a==NULL) return ntCopy(b,cf);
+  if (b==NULL) return ntCopy(a,cf);
+#ifdef HAVE_FACTORY  
+  fraction fa = (fraction)a;
+  fraction fb = (fraction)b;
+  /* singclap_gcd destroys its arguments; we hence need copies: */
+  poly pa = p_Copy(NUM(fa), ntRing);
+  poly pb = p_Copy(NUM(fb), ntRing);
+  
+  /* Note that, over Q, singclap_gcd will remove the denominators in all
+     rational coefficients of pa and pb, before starting to compute
+     the gcd. Thus, we do not need to ensure that the coefficients of
+     pa and pb live in Z; they may well be elements of Q\Z. */
+  poly pGcd = singclap_gcd(pa, pb, cf->extRing);
+  fraction result = (fraction)omAlloc0Bin(fractionObjectBin);
+  NUM(result) = pGcd;
+  return (number)result;
+#else
+  Print("// factory needed: transext.cc:ntGcd\n");
   return NULL;
+#endif /* HAVE_FACTORY */
 }