Changeset 3216ec in git for libpolys/coeffs/longrat.cc

Timestamp:

Aug 15, 2012, 1:44:30 PM (10 years ago)

Author:

Hans Schoenemann <hannes@…>

Branches:

(u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', 'ad2543eab51733612ba7d118afc77edca719600e')

Children:

d8b0997ff6f148513d95e2f2a5a075c7386c7168

Parents:

a8ead8e63f3539f8915726efa18791dcc052733a

Message:

add: extgcd for bigint

File:

• libpolys/coeffs/longrat.cc (modified) (3 diffs)

libpolys/coeffs/longrat.cc

@@ -2605 +2605 @@
 }
 
+number nlExtGcd(number a, number b, number *s, number *t, const coeffs)
+{
+  mpz_t aa,bb;
+  *s=ALLOC_RNUMBER();
+  mpz_init((*s)->z); (*s)->s=3;
+  (*t)=ALLOC_RNUMBER();
+  mpz_init((*t)->z); (*t)->s=3;
+  number g=ALLOC_RNUMBER();
+  mpz_init(g->z); g->s=3;
+  if (SR_HDL(a) & SR_INT)
+  {
+    mpz_init_set_si(aa,SR_TO_INT(a));
+  }
+  else
+  {
+    mpz_init_set(aa,a->z);
+  }
+  if (SR_HDL(b) & SR_INT)
+  {
+    mpz_init_set_si(bb,SR_TO_INT(b));
+  }
+  else
+  {
+    mpz_init_set(bb,b->z);
+  }
+  mpz_gcdext(g->z,(*s)->z,(*t)->z,aa,bb);
+  mpz_clear(aa);
+  mpz_clear(bb);
+  (*s)=nlShort3((*s));
+  (*t)=nlShort3((*t));
+  g=nlShort3(g);
+  return g;
+}
+
 void    nlCoeffWrite  (const coeffs, BOOLEAN /*details*/)
 {
@@ -2816 +2850 @@
   //r->cfIsUnit = NULL; // only for ring stuff
   //r->cfGetUnit = NULL; // only for ring stuff
-  //r->cfExtGcd = NULL; // only for ring stuff
   //r->cfDivBy = NULL; // only for ring stuff
   #endif
@@ -2837 +2870 @@
   r->cfGetNumerator = nlGetNumerator;
   r->cfGcd  = nlGcd;
+  r->cfExtGcd = nlExtGcd; // only for ring stuff and Z
   r->cfLcm  = nlLcm;
   r->cfDelete= nlDelete;