Merge pull request #326 from mohabsafey/bug-fix-lifting-gb

Bug fix in lifting gb (case of empty elim basis) + warning msg fixed

Author: ederc

Makefile.am

@@ -26,6 +26,7 @@ checkdiff               = test/diff/diff_bug-2nd-prime-bad.sh \
 			  test/diff/diff_eco6-qq.sh \
 			  test/diff/diff_elim-31.sh \
 			  test/diff/diff_elim-qq.sh \
+			  test/diff/diff_empty-elim-qq.sh \
 			  test/diff/diff_f4sat-31.sh \
 			  test/diff/diff_f4sat-byone-31.sh \
 			  test/diff/diff_f4sat-field-char.sh \

configure.ac

@@ -158,6 +158,10 @@ AC_CONFIG_LINKS([
  output_files/elim-qq.g2.e1.res:output_files/elim-qq.g2.e1.res
  output_files/elim-qq.g2.e2.res:output_files/elim-qq.g2.e2.res
  test/diff/diff_elim-qq.sh:test/diff/diff_elim-qq.sh
+ input_files/empty-elim-qq.ms:input_files/empty-elim-qq.ms
+ output_files/empty-elim-qq.g2.e1.res:output_files/empty-elim-qq.g2.e1.res
+ output_files/empty-elim-qq.g2.e2.res:output_files/empty-elim-qq.g2.e2.res
+ test/diff/diff_empty-elim-qq.sh:test/diff/diff_empty-elim-qq.sh
  input_files/f4sat-31.ms:input_files/f4sat-31.ms
  output_files/f4sat-31.res:output_files/f4sat-31.res
  test/diff/diff_f4sat-31.sh:test/diff/diff_f4sat-31.sh

input_files/empty-elim-qq.ms

@@ -0,0 +1,5 @@
+x, y, z
+0
+x^2-2, 
+y^2-3
+

output_files/empty-elim-qq.g2.e1.res

@@ -0,0 +1,8 @@
+#Reduced Groebner basis data
+#---
+#field characteristic: 0
+#variable order:       y, z
+#monomial order:       graded reverse lexicographical
+#length of basis:      1 element
+#---
+[y^2-3]:

output_files/empty-elim-qq.g2.e2.res

@@ -0,0 +1,8 @@
+#Reduced Groebner basis data
+#---
+#field characteristic: 0
+#variable order:       z
+#monomial order:       graded reverse lexicographical
+#length of basis:      0 elements sorted by increasing leading monomials
+#---
+[0]:

src/msolve/lifting-gb.c

@@ -1099,14 +1099,12 @@ static inline int verif_lifted_basis(gb_modpoly_t modgbs, data_lift_t dl,
           if(dl->check2[k] == NBCHECK){
             dl->S = k+1;
             dl->lstart = dl->S;
-            if(modgbs->modpolys[k] != NULL){
-              for(uint32_t j = 0; j < modgbs->modpolys[k]->len; j++){
-                free(modgbs->modpolys[k]->cf_32[j]);
-                mpz_clear(modgbs->modpolys[k]->cf_zz[j]);
-              }
-              free(modgbs->modpolys[k]->cf_32);
-              free(modgbs->modpolys[k]->cf_zz);
+            for(uint32_t j = 0; j < modgbs->modpolys[k]->len; j++){
+              free(modgbs->modpolys[k]->cf_32[j]);
+              mpz_clear(modgbs->modpolys[k]->cf_zz[j]);
             }
+            free(modgbs->modpolys[k]->cf_32);
+            free(modgbs->modpolys[k]->cf_zz);
           }
         }
       }
@@ -1352,7 +1350,7 @@ gb_modpoly_t *core_groebner_qq(
                                                  0,
                                                  maxbitsize,
                                                  &success);
-    if(is_empty == 1 || print_gb == 1){
+    if(is_empty == 1 || print_gb == 1 || (*modgbsp)->ld == 0){
       if(dlinit){
         data_lift_clear(dlift);
       }

test/diff/diff_empty-elim-qq.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+file=empty-elim-qq
+
+source test/diff/diff_source.sh
+
+source test/diff/diff_source-gb-elim-red.sh
+
+normal_exit