def get_single_level_center_point(self, featmap_size, stride,
                                      cell_offset=0):
        """
        Generate pixel centers of a single stage feature map.
        Args:
            featmap_size: height and width of the feature map
            stride: down sample stride of the feature map
        Returns:
            y and x of the center points
        """
        h, w = featmap_size
        x_range = (paddle.arange(w, dtype='float32') + cell_offset) * stride
        y_range = (paddle.arange(h, dtype='float32') + cell_offset) * stride
        y, x = paddle.meshgrid(y_range, x_range)
        y = y.flatten()
        x = x.flatten()
        return y, x

        Generate pixel centers of a single stage feature map.
        Args:
            featmap_size: height and width of the feature map
            stride: down sample stride of the feature map
        Returns:
            y and x of the center points
        
ppdet/modeling/heads/gfl_head.py