         {
             int nonzero_idx = threadIdx.x + (ITEM * BLOCK_THREADS);
 
+            ColumnIndicesIteratorT ci = wd_column_indices + tile_start_coord.y + nonzero_idx;
+            ValueIteratorT a = wd_values + tile_start_coord.y + nonzero_idx;
+
             if (nonzero_idx < tile_num_nonzeros)
             {
 

            row_indices[ITEM] = thread_current_coord.x;
        }

        // Block-wide reduce-value-by-segment
        KeyValuePairT       tile_carry;
        ReduceBySegmentOpT  scan_op;

            // Smem needed for block exchange
            typename BlockExchangeT::TempStorage exchange;

            // Smem needed for block-wide reduction
            typename BlockReduceT::TempStorage reduce;

