From 49b7480ebc6b89c61ea6555f8f339873abbac069 Mon Sep 17 00:00:00 2001
From: Oleksandr Motsak <motsak@mathematik.uni-kl.de>
Date: Wed, 27 May 2015 21:23:30 +0200
Subject: [PATCH] Bug fixed in idMinors (wrong ring at idDelete) + code cleanup

---
 kernel/ideals.cc | 70 +++++++++++++++++++++++++++++-------------------
 1 file changed, 43 insertions(+), 27 deletions(-)

diff --git a/kernel/ideals.cc b/kernel/ideals.cc
index e38f07b264..f2f82fca6e 100644
--- a/kernel/ideals.cc
+++ b/kernel/ideals.cc
@@ -1780,52 +1780,68 @@ ideal idMinors(matrix a, int ar, ideal R)
   return (result);
 }
 #else
-/*2
-* compute all ar-minors of the matrix a
-* the caller of mpRecMin
-* the elements of the result are not in R (if R!=NULL)
-*/
+
+
+/// compute all ar-minors of the matrix a
+/// the caller of mpRecMin
+/// the elements of the result are not in R (if R!=NULL)
 ideal idMinors(matrix a, int ar, ideal R)
 {
-  int elems=0;
-  int r=a->nrows,c=a->ncols;
-  int i;
-  matrix b;
-  ideal result,h;
-  ring origR=currRing;
-  ring tmpR;
-  long bound;
+ 
+  const ring origR=currRing;
+  id_Test((ideal)a, origR);
 
+  const int r = a->nrows;
+  const int c = a->ncols;
+  
   if((ar<=0) || (ar>r) || (ar>c))
   {
     Werror("%d-th minor, matrix is %dx%d",ar,r,c);
     return NULL;
   }
-  h = id_Matrix2Module(mp_Copy(a,origR),origR);
-  bound = sm_ExpBound(h,c,r,ar,origR);
-  idDelete(&h);
-  tmpR=sm_RingChange(origR,bound);
-  b = mpNew(r,c);
-  for (i=r*c-1;i>=0;i--)
-  {
-    if (a->m[i])
+  
+  ideal h = id_Matrix2Module(mp_Copy(a,origR),origR);  
+  long bound = sm_ExpBound(h,c,r,ar,origR);
+  id_Delete(&h, origR);
+  
+  ring tmpR = sm_RingChange(origR,bound);
+  
+  matrix b = mpNew(r,c);
+  
+  for (int i=r*c-1;i>=0;i--)
+    if (a->m[i] != NULL)
       b->m[i] = prCopyR(a->m[i],origR,tmpR);
-  }
+  
+  id_Test( (ideal)b, tmpR);
+  
   if (R!=NULL)
   {
-    R = idrCopyR(R,origR,tmpR);
+    R = idrCopyR(R,origR,tmpR); // TODO: overwrites R? memory leak?
     //if (ar>1) // otherwise done in mpMinorToResult
     //{
     //  matrix bb=(matrix)kNF(R,currRing->qideal,(ideal)b);
     //  bb->rank=b->rank; bb->nrows=b->nrows; bb->ncols=b->ncols;
     //  idDelete((ideal*)&b); b=bb;
     //}
+    id_Test( R, tmpR);
   }
-  result=idInit(32,1);
-  if(ar>1) mp_RecMin(ar-1,result,elems,b,r,c,NULL,R,tmpR);
-  else mp_MinorToResult(result,elems,b,r,c,R,tmpR);
-  idDelete((ideal *)&b);
+  
+  
+  ideal result = idInit(32,1);
+
+  int elems = 0;
+  
+  if(ar>1)
+    mp_RecMin(ar-1,result,elems,b,r,c,NULL,R,tmpR);
+  else
+    mp_MinorToResult(result,elems,b,r,c,R,tmpR);
+  
+  id_Test( (ideal)b, tmpR);
+  
+  id_Delete((ideal *)&b, tmpR);
+  
   if (R!=NULL) idDelete(&R);
+  
   idSkipZeroes(result);
   rChangeCurrRing(origR);
   result = idrMoveR(result,tmpR,origR);