1 files changed, 1 insertions, 1 deletions
diff --git a/transfer.c b/transfer.c
index 6c8f614..046d96d 100644
--- a/transfer.c
+++ b/transfer.c
@@ -98,7 +98,7 @@ static int transfer_factors_lagrange(GridTransferContext *ctx, unsigned int dim)
         return -ENOMEM;
 
     for (ptrdiff_t idx_dst = 0; idx_dst < ctx->dst.size[dim]; idx_dst++) {
-        const ptrdiff_t idx_src = scale * idx_dst - (priv->stencil / 2 - 1);
+        const ptrdiff_t idx_src = (ptrdiff_t)(scale * idx_dst) - (priv->stencil / 2 - 1);
         const double coord_dst  = idx_dst * step_dst;
 
         double *fact = priv->fact[dim] + priv->stencil * idx_dst;