Changeset 36914e in git

Timestamp:

Mar 7, 2014, 2:11:05 PM (10 years ago)

Author:

Martin Lee <martinlee84@…>

Branches:

(u'spielwiese', '8e0ad00ce244dfd0756200662572aef8402f13d5')

Children:

48686414f84cb721633f002b70fc8550f00a41d5

Parents:

40227ae7c2daf35e8c370108cbc9726d208d6ba8

git-author:

Martin Lee <martinlee84@web.de>2014-03-07 14:11:05+01:00

git-committer:

Hans Schoenemann <hannes@mathematik.uni-kl.de>2014-03-17 18:31:54+01:00

Message:

chg: added QuasiInverse over alg. function field

File:

• factory/libfac/charset/alg_factor.cc (modified) (1 diff)

factory/libfac/charset/alg_factor.cc

@@ -464 +464 @@
       r= swapvar (r, x, X);
     }
+}
+
+CanonicalForm
+QuasiInverse (const CanonicalForm& f, const CanonicalForm& g,
+      CanonicalForm& numt, const Variable& x)
+{
+  CanonicalForm pi, pi1, q, t0, t1, Hi, bi, pi2;
+  bool isRat= isOn (SW_RATIONAL);
+  CanonicalForm m,tmp;
+  if (isRat)
+    Off (SW_RATIONAL);
+  pi= f/content (f,x);
+  pi1= g/content (g,x);
+
+  t0= 0;
+  t1= 1;
+  bi= 1;
+
+  On (SW_RATIONAL);
+
+  int delta= degree (f, x) - degree (g, x);
+  Hi= power (LC (pi1, x), delta);
+  if ( (delta+1) % 2 )
+      bi = 1;
+  else
+      bi = -1;
+
+  while (degree (pi1,x) > 0)
+  {
+    On (SW_RATIONAL);
+    psqr( pi, pi1, q, pi2, m, x);
+    pi2 /= bi;
+
+    tmp= t1;
+    t1= t0*m - t1*q;
+    t0= tmp;
+    t1 /= bi;
+    pi = pi1; pi1 = pi2;
+    if ( degree ( pi1, x ) > 0 )
+    {
+      delta = degree( pi, x ) - degree( pi1, x );
+      if ( (delta+1) % 2 )
+        bi = LC( pi, x ) * power( Hi, delta );
+      else
+        bi = -LC( pi, x ) * power( Hi, delta );
+      Hi = power( LC( pi1, x ), delta ) / power( Hi, delta-1 );
+    }
+  }
+  t1 /= gcd (pi1, t1);
+  if (!isRat)
+    Off (SW_RATIONAL);
+  numt= t1;
+  return pi;
 }