Changeset 19ee5eb in git

Timestamp:

Feb 1, 2021, 1:32:52 PM (2 years ago)

Author:

Hans Schoenemann <hannes@…>

Branches:

(u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', 'cdfcdb8287f66bc6070028082cbbc6eff10e609b')

Children:

4218c13e2434358d0a056b78d0a40377a11bcdb1

Parents:

f60ab1f6c47a09dc3472f9d3cabd270622c46327

Message:

fix: division by 0: return 0, not NULL

Location:

libpolys/coeffs

Files:

• flintcf_Qrat.cc (modified) (2 diffs)
• gnumpc.cc (modified) (2 diffs)
• gnumpfl.cc (modified) (2 diffs)
• modulop.cc (modified) (1 diff)
• rintegers2.cc (modified) (2 diffs)
• rintegers3.cc (modified) (3 diffs)
• rmodulo2m.cc (modified) (1 diff)
• rmodulon.cc (modified) (3 diffs)

libpolys/coeffs/flintcf_Qrat.cc

@@ -446 +446 @@
   const fmpq_rat_ptr y = (fmpq_rat_ptr) b;
   const fmpq_ctx_ptr ctx = (fmpq_ctx_ptr) ((data_ptr)c->data)->ctx;
-  if (fmpq_mpoly_is_zero(y->num, ctx))
-  {
-    WerrorS(nDivBy0);
-    return NULL;
-  }
   fmpq_rat_ptr res = (fmpq_rat_ptr) omAlloc(sizeof(fmpq_rat_struct));
   fmpq_rat_init(res, c);
+  if (fmpq_mpoly_is_zero(y->num, ctx))
+  {
+    WerrorS(nDivBy0);
+    return (number)res;
+  }
   if (fmpq_mpoly_equal(x->den, y->num, ctx)) /* denominators equal */
   {
@@ -531 +531 @@
 static number ExactDiv(number a, number b, const coeffs c)
 {
-  fmpq_rat_ptr res = (fmpq_rat_ptr) omAlloc(sizeof(fmpq_rat_struct));
   const fmpq_rat_ptr x = (fmpq_rat_ptr) a;
   const fmpq_rat_ptr y = (fmpq_rat_ptr) b;
   const fmpq_ctx_ptr ctx = (fmpq_ctx_ptr) ((data_ptr)c->data)->ctx;
+  fmpq_rat_ptr res = (fmpq_rat_ptr) omAlloc(sizeof(fmpq_rat_struct));
+  fmpq_rat_init(res, c);
   if (fmpq_mpoly_is_zero(y->num, ctx))
   {
      WerrorS(nDivBy0);
-     return NULL;
-  }
-  fmpq_rat_init(res, c);
+     return (number)res;
+  }
   fmpq_mpoly_div(res->num, x->num, y->num, ctx);
   assume(fmpq_mpoly_is_one(x->den, ctx));

libpolys/coeffs/gnumpc.cc

@@ -142 +142 @@
   {
     WerrorS(nDivBy0);
+    r = new gmp_complex( 0 );
   }
   else
@@ -194 +195 @@
     // a/0 = error
     WerrorS(nDivBy0);
-    return NULL;
+    return (number)new gmp_complex( 0 );
   }
   gmp_complex* res = new gmp_complex( (*(gmp_complex*)a) / (*(gmp_complex*)b) );

libpolys/coeffs/gnumpfl.cc

@@ -139 +139 @@
   {
     WerrorS(nDivBy0);
+    f= new gmp_float( 0 );
   }
   else
@@ -186 +187 @@
 {
   assume( getCoeffType(r) == n_long_R );
-
+  
+  gmp_float* f;
   if ( ((gmp_float*)b)->isZero() )
   {
     // a/0 = error
     WerrorS(nDivBy0);
-    return NULL;
-  }
-  gmp_float* f= new gmp_float( (*(gmp_float*)a) / (*(gmp_float*)b) );
+    f= new gmp_float( 0 );
+  }
+  else
+  {
+    f= new gmp_float( (*(gmp_float*)a) / (*(gmp_float*)b) );
+  }
   return (number)f;
 }

libpolys/coeffs/modulop.cc

@@ -234 +234 @@
   else
   {
-    if ((z==0)&&(n==0)) WerrorS(nDivBy0);
+    if ((z==0)&&(n==0))
+    {
+      WerrorS(nDivBy0);
+      *a=(number)0L;
+    }
     else
     {

libpolys/coeffs/rintegers2.cc

@@ -227 +227 @@
 }
 
-static number nrzDiv (number a,number b, const coeffs)
-{
-  mpz_ptr erg = (mpz_ptr) omAllocBin(gmp_nrz_bin);
-  mpz_init(erg);
-  mpz_ptr r = (mpz_ptr) omAllocBin(gmp_nrz_bin);
-  mpz_init(r);
-  mpz_tdiv_qr(erg, r, (mpz_ptr) a, (mpz_ptr) b);
-  //if (!nrzIsZero((number) r, R))
-  //{
-  //  WerrorS("Division by non divisible element.");
-  //  WerrorS("Result is without remainder.");
-  //}
-  mpz_clear(r);
-  omFreeBin(r, gmp_nrz_bin);
-  return (number) erg;
-}
-
-static number nrzExactDiv (number a,number b, const coeffs)
-{
-  mpz_ptr erg = (mpz_ptr) omAllocBin(gmp_nrz_bin);
-  mpz_init(erg);
-  mpz_tdiv_q(erg, (mpz_ptr) a, (mpz_ptr) b);
+static number nrzDiv (number a,number b, const coeffs r)
+{
+  mpz_ptr erg = (mpz_ptr) omAllocBin(gmp_nrz_bin);
+  mpz_init(erg);
+  if (nrzIsZero(b,r))
+  {
+    WerrorS(nDivBy0);
+  }
+  else
+  {
+    mpz_ptr r = (mpz_ptr) omAllocBin(gmp_nrz_bin);
+    mpz_init(r);
+    mpz_tdiv_qr(erg, r, (mpz_ptr) a, (mpz_ptr) b);
+    mpz_clear(r);
+    omFreeBin(r, gmp_nrz_bin);
+  }
+  return (number) erg;
+}
+
+static number nrzExactDiv (number a,number b, const coeffs r)
+{
+  mpz_ptr erg = (mpz_ptr) omAllocBin(gmp_nrz_bin);
+  mpz_init(erg);
+  if (nrzIsZero(b,r))
+  {
+    WerrorS(nDivBy0);
+  }
+  else
+  {
+    mpz_tdiv_q(erg, (mpz_ptr) a, (mpz_ptr) b);
+  }
   return (number) erg;
 }
@@ -331 +340 @@
   {
     WerrorS("Non invertible element.");
-    return (number)NULL;
+    return nrzInit(0,r);
   }
   return nrzCopy(c,r);

libpolys/coeffs/rintegers3.cc

@@ -744 +744 @@
 {
   assume(SR_TO_INT(b));
-  if (n_Z_IS_SMALL(a) && n_Z_IS_SMALL(b))
+  if (nrzIsZero(b))
+  {
+    WerrorS(nDivBy0);
+    return INT_TO_SR(0);
+  }
+  else if (n_Z_IS_SMALL(a) && n_Z_IS_SMALL(b))
   {
     //if (SR_TO_INT(a) % SR_TO_INT(b))
@@ -810 +815 @@
   assume(SR_TO_INT(b));
   mpz_t aa, bb;
-  if (n_Z_IS_SMALL(a))
+  if (nrzIsZero(b))
+  {
+    WerrorS(nDivBy0);
+    return INT_TO_SR(0);
+  }
+  else if (n_Z_IS_SMALL(a))
     mpz_init_set_si(aa, SR_TO_INT(a));
   else
@@ -857 +867 @@
   {
     WerrorS("Non invertible element.");
-    return (number)NULL;
+    return nrzInit(0,r);
   }
   return c; // has to be 1 or -1....

libpolys/coeffs/rmodulo2m.cc

@@ -412 +412 @@
       }
     }
-    if ((unsigned long)b % 2 == 0)
+    if ((long)b==0L)
+    {
+      WerrorS(nDivBy0);
+      return (number)0L;
+    }
+    else if ((unsigned long)b % 2 == 0)
     {
       WerrorS("Division not possible, even by cancelling zero divisors.");

libpolys/coeffs/rmodulon.cc

@@ -248 +248 @@
   mpz_ptr erg = (mpz_ptr)omAllocBin(gmp_nrz_bin);
   mpz_init(erg);
-  mpz_invert(erg, (mpz_ptr)c, r->modNumber);
+  if (nrnIsZero(c,r))
+  {
+    WerrorS(nDivBy0);
+  }
+  else
+  {
+    mpz_invert(erg, (mpz_ptr)c, r->modNumber);
+  }
   return (number) erg;
 }
@@ -547 +554 @@
 static number nrnDiv(number a, number b, const coeffs r)
 {
-  if (r->is_field)
+  if (nrnIsZero(b,r))
+  {
+    WerrorS(nDivBy0);
+    return nrnInit(0,r);
+  }
+  else if (r->is_field)
   {
     number inv=nrnInvers(b,r);
@@ -613 +625 @@
   omFreeBin(g, gmp_nrz_bin);
   return (number)rr;
-}
-
-static number nrnIntDiv(number a, number b, const coeffs r)
-{
-  mpz_ptr erg = (mpz_ptr)omAllocBin(gmp_nrz_bin);
-  mpz_init(erg);
-  mpz_tdiv_q(erg, (mpz_ptr)a, (mpz_ptr)b);
-  return (number)erg;
 }