def _grid_cells_to_center(self, grid_cells):
        """
        Get center location of each gird cell
        Args:
            grid_cells: grid cells of a feature map
        Returns:
            center points
        """
        cells_cx = (grid_cells[:, 2] + grid_cells[:, 0]) / 2
        cells_cy = (grid_cells[:, 3] + grid_cells[:, 1]) / 2
        return paddle.stack([cells_cx, cells_cy], axis=-1)

        Get center location of each gird cell
        Args:
            grid_cells: grid cells of a feature map
        Returns:
            center points
        
ppdet/modeling/heads/gfl_head.py