added an assert

diff --git a/lib/sparse/SparseMatrix.c b/lib/sparse/SparseMatrix.c
index 2973d8642773db360a7834356650d8bb82865bab..42e8d34439f9ef686353ae909dcbb6ee4191840a 100644 (file)
--- a/lib/sparse/SparseMatrix.c
+++ b/lib/sparse/SparseMatrix.c
@@ -1610,6 +1610,7 @@ SparseMatrix SparseMatrix_sum_repeat_entries(SparseMatrix A, int what_to_sum){
 SparseMatrix SparseMatrix_coordinate_form_add_entries(SparseMatrix A, int nentries, int *irn, int *jcn, void *val){
   int nz, type = A->type, nzmax, i;
   
+  assert(A);
   assert(A->format == FORMAT_COORD);
   if (nentries <= 0) return A;
   nz = A->nz;