Changeset 4f9652 in git

Timestamp:

Aug 2, 2012, 3:33:00 PM (12 years ago)

Author:

Hans Schoenemann <hannes@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

d7ad81d4a58a77b7c782dc91c68ba5aa2a7f148c

Parents:

188de86ff46e2712a74ba7395b129a90c6d0b3f5

git-author:

Hans Schoenemann <hannes@mathematik.uni-kl.de>2012-08-02 15:33:00+02:00

git-committer:

Hans Schoenemann <hannes@mathematik.uni-kl.de>2012-08-02 16:10:41+02:00

Message:

add: nlClearContent

File:

• libpolys/coeffs/longrat.cc (modified) (2 diffs)

libpolys/coeffs/longrat.cc

@@ -2637 +2637 @@
 }
 
-static void nlClearContent(ICoeffsEnumerator& /*numberCollectionEnumerator*/, number& c, const coeffs cf)
+static void nlClearContent(ICoeffsEnumerator& numberCollectionEnumerator, number& c, const coeffs cf)
 {
   assume(cf != NULL);
@@ -2643 +2643 @@
   // all coeffs are given by integers!!!
 
-  c = n_Init(1, cf);
-  assume(FALSE); // TODO: NOT YET IMPLEMENTED!!!
-
-//   numberCollectionEnumerator.Reset();
-// 
-//   c = numberCollectionEnumerator.Current();
-// 
-//   n_Normalize(c, r);
-// 
-//   if (!n_IsOne(c, r))
-//   {    
-//     numberCollectionEnumerator.Current() = n_Init(1, r); // ???
-// 
-//     number inv = n_Invers(c, r);
-// 
-//     while( numberCollectionEnumerator.MoveNext() )
-//     {
-//       number &n = numberCollectionEnumerator.Current();
-//       n_Normalize(n, r); // ?
-//       n_InpMult(n, inv, r);
-//     }
-// 
-//     n_Delete(&inv, r);
-//   }
+  // part 1, find a small candidate for gcd
+  number cand1,cand;
+  int s1,s;
+  s=2147483647; // max. int
+  numberCollectionEnumerator.Reset();
+  do
+  {
+    cand1= numberCollectionEnumerator.Current();
+    if (SR_HDL(cand1)&SR_INT) { cand=cand1;break;}
+    s1=mpz_size1(cand1->z);
+    if (s>s1)
+    {
+      cand=cand1;
+      s=s1;
+    }
+  } while (numberCollectionEnumerator.MoveNext() ); 
+ 
+  // part 2: compute gcd(cand,all coeffs)
+  numberCollectionEnumerator.Reset();
+  do
+  {
+    nlNormalize(numberCollectionEnumerator.Current(),cf);
+    cand1= nlGcd(cand,numberCollectionEnumerator.Current(),cf);
+    nlDelete(&cand,cf);
+    cand=cand1;
+    if(nlIsOne(cand,cf)) { c=cand; return; }
+  } while (numberCollectionEnumerator.MoveNext() ); 
+ 
+  // part3: all coeffs = all coeffs / cand
+  c=cand;
+  numberCollectionEnumerator.Reset();
+  do
+  {
+    number t=nlIntDiv(numberCollectionEnumerator.Current(),cand,cf);
+    nlDelete(&numberCollectionEnumerator.Current(),cf);
+    numberCollectionEnumerator.Current()=t;
+  } while (numberCollectionEnumerator.MoveNext() ); 
+ 
 }