diff --git a/src/operator/correlation1D.cu b/src/operator/correlation1D.cu
index cc6ee8aac89b..6eab51854bb3 100644
--- a/src/operator/correlation1D.cu
+++ b/src/operator/correlation1D.cu
@@ -290,7 +290,7 @@ void Forward_gpu(
      
     int x_shift = - neighborhood_grid_radius_;
     if(single_side == -1) { // to the left
-      x_shift = -neighborhood_grid_width_;
+      x_shift = -neighborhood_grid_radius_;
     } else if(single_side == 1) { // to the right
       x_shift = 0;
     }
@@ -338,7 +338,7 @@ void Backward_gpu(
     
     int x_shift = - neighborhood_grid_radius_;
     if (single_side == -1) { // to the left
-      x_shift = -neighborhood_grid_width_;
+      x_shift = -neighborhood_grid_radius_;
     } else if(single_side == 1) { // to the right
       x_shift = 0;
     }