Changeset 8cfc91 in git

Timestamp:

Apr 9, 2019, 3:34:09 PM (4 years ago)

Author:

Hans Schoenemann <hannes@…>

Branches:

(u'spielwiese', '8d54773d6c9e2f1d2593a28bc68b7eeab54ed529')

Children:

fcf6c47c06265d4de6796b8f705ab3c850722903

Parents:

71d8cc963194f7a7d75dd63c8856982987161c3c

Message:

fix: better limit for overflow test in subst

Files:

• Singular/iparith.cc (modified) (2 diffs)
• libpolys/polys/monomials/p_polys.cc (modified) (1 diff)
• libpolys/polys/monomials/p_polys.h (modified) (1 diff)

Singular/iparith.cc

@@ -6550 +6550 @@
   if (ringvar>0)
   {
-    if ((monomexpr!=NULL) && (p!=NULL) && (pTotaldegree(p)!=0) &&
-    ((unsigned long)pTotaldegree(monomexpr) > (currRing->bitmask / (unsigned long)pTotaldegree(p)/2)))
-    {
-      Warn("possible OVERFLOW in subst, max exponent is %ld, substituting deg %d by deg %d",currRing->bitmask/2, pTotaldegree(monomexpr), pTotaldegree(p));
+    int mm=p_MaxExpPerVar(p,ringvar,currRing);
+    if ((monomexpr!=NULL) && (p!=NULL) && (mm!=0) &&
+    ((unsigned long)pTotaldegree(monomexpr) > (currRing->bitmask / (unsigned long)mm/2)))
+    {
+      Warn("possible OVERFLOW in subst, max exponent is %ld, substituting deg %d by deg %d",currRing->bitmask/2, pTotaldegree(monomexpr), mm);
       //return TRUE;
     }
@@ -6583 +6584 @@
       {
         poly p=id->m[i];
-        if ((p!=NULL) && (pTotaldegree(p)!=0) &&
-        ((unsigned long)deg_monexp > (currRing->bitmask / (unsigned long)pTotaldegree(p)/2)))
+        int mm=p_MaxExpPerVar(p,ringvar,currRing);
+        if ((p!=NULL) && (mm!=0) &&
+        ((unsigned long)deg_monexp > (currRing->bitmask / (unsigned long)mm/2)))
         {
           overflow=TRUE;

libpolys/polys/monomials/p_polys.cc

@@ -4895 +4895 @@
 }
 
+int p_MaxExpPerVar(poly p, int i, const ring r)
+{
+  int m=0;
+  while(p!=NULL)
+  {
+    int mm=p_GetExp(p,i,r);
+    if (mm>m) m=mm;
+    pIter(p);
+  }
+  return m;
+}
+

libpolys/polys/monomials/p_polys.h

@@ -2085 +2085 @@
 /// divide polynomial by monomial
 poly p_Div_mm(poly p, const poly m, const ring r);
+
+
+/// max exponent of variable x_i in p
+int p_MaxExpPerVar(poly p, int i, const ring r);
 #endif // P_POLYS_H