fix/add implicit padding with zeros

Author: j-danner

m4ri/solve.c

@@ -36,14 +36,6 @@ int mzd_solve_left(mzd_t *A, mzd_t *B, int const cutoff, int const inconsistency
     m4ri_die("mzd_solve_left: B nrows (%d) must be equal to max of A nrows (%d) and A ncols (%d).\n", B->nrows,
              A->nrows, A->ncols);
 
-  if (inconsistency_check && B->nrows > A->nrows) {
-    mzd_t const *Bpad = mzd_init_window_const(B, A->nrows+1, 0, B->nrows, B->ncols);
-    if(!mzd_is_zero(Bpad))
-      m4ri_die("mzd_solve_left: if B nrows (%d) is bigger than A nrows (%d) the additional rows must be zero.\n", B->nrows,
-               A->nrows, A->ncols);
-    mzd_free_window((mzd_t *) Bpad);
-  }
-
   return _mzd_solve_left(A, B, cutoff, inconsistency_check);
 }
 
@@ -128,6 +120,12 @@ int _mzd_pluq_solve_left(mzd_t const *A, rci_t rank, mzp_t const *P, mzp_t const
 }
 
 int _mzd_solve_left(mzd_t *A, mzd_t *B, int const cutoff, int const inconsistency_check) {
+  if (inconsistency_check && B->nrows > A->nrows) {
+    mzd_t const *Bpad = mzd_init_window_const(B, A->nrows+1, 0, B->nrows, B->ncols);
+    if(!mzd_is_zero(Bpad)) return -1;
+    mzd_free_window((mzd_t *) Bpad);
+  }
+
   /**
    *  B is modified in place
    *  (Bi's in the comments are just modified versions of B)

m4ri/solve.h

@@ -36,6 +36,8 @@
  * \brief Solves A X = B with A and B matrices.
  *
  * The solution X is stored inplace on B.
+ * If A->nrows < A->ncols, the matrix A is implicitly padded with zeros to
+ * match B->nrows.
  *
  * \param A Input matrix (overwritten).
  * \param B Input matrix, being overwritten by the solution matrix X