ell_grid_solve: do not read from outside of allocated boundary values

1 files changed, 1 insertions, 1 deletions

diff --git a/ell_grid_solve.c b/ell_grid_solve.c
index 9d50c82..1952f95 100644
--- a/ell_grid_solve.c
+++ b/ell_grid_solve.c
@@ -420,7 +420,7 @@ static int solve_exact(EGSContext *ctx)
                             continue;
 
                         for (ptrdiff_t bnd_layer = 1; bnd_layer < ctx->fd_stencil; bnd_layer++)
-                            for (ptrdiff_t bnd_idx = -(ptrdiff_t)ctx->fd_stencil; bnd_idx < (ptrdiff_t)(bnd_len[0] + ctx->fd_stencil); bnd_idx++) {
+                            for (ptrdiff_t bnd_idx = -((ptrdiff_t)ctx->fd_stencil - 1); bnd_idx < (ptrdiff_t)(bnd_len[0] + ctx->fd_stencil - 1); bnd_idx++) {
                                 e->rhs[mat_row_idx] -= bnd->val[bnd_layer * bnd->val_stride + bnd_idx] * dst[dir * bnd_layer * bnd_stride[1] + bnd_idx * bnd_stride[0]];
                                 dst[dir * bnd_layer * bnd_stride[1] + bnd_idx * bnd_stride[0]] = 0.0;
                             }