egs: optimize applying reflection boundaries

1 files changed, 8 insertions, 3 deletions

diff --git a/ell_grid_solve.c b/ell_grid_solve.c
index 6c8a863..9aee0e8 100644
--- a/ell_grid_solve.c
+++ b/ell_grid_solve.c
@@ -147,11 +147,16 @@ static void boundaries_apply_reflect(double *dst, const ptrdiff_t dst_stride[2],
                                      const double *src, ptrdiff_t src_stride,
                                      size_t boundary_size)
 {
-    for (size_t i = 0; i < boundary_size; i++) {
+    if (dst_stride[0] == 1) {
         for (int j = 1; j <= FD_STENCIL_MAX; j++)
-            dst[dst_stride[1] * j] = dst[-dst_stride[1] * j];
+            memcpy(dst + j * dst_stride[1], dst - j * dst_stride[1], sizeof(*dst) * boundary_size);
+    } else {
+        for (size_t i = 0; i < boundary_size; i++) {
+            for (int j = 1; j <= FD_STENCIL_MAX; j++)
+                dst[dst_stride[1] * j] = dst[-dst_stride[1] * j];
 
-        dst += dst_stride[0];
+            dst += dst_stride[0];
+        }
     }
 }