code: def gram_matrix(v):
      assert isinstance(v, tf.Tensor)
      v.get_shape().assert_has_rank(4)
      dim = v.get_shape().as_list()
      v = tf.reshape(v, [-1, dim[1] * dim[2], dim[3]])
      return tf.matmul(v, v, transpose_a=True)
  
imports: import argparse
  import numpy
  import os
  import cv2
  import six
  import tensorflow
  from tensorpack import *
  from tensorpack.tfutils.scope_utils import auto_reuse_variable_scope
  from tensorpack.tfutils.summary import add_moving_summary
  from tensorpack.utils import logger
  from tensorpack.utils.gpu import get_num_gpu
  from data_sampler import CenterSquareResize, ImageDataFromZIPFile, ImageDecode, RejectTooSmallImages
  from GAN import GANModelDesc, SeparateGANTrainer
label_desc: Use image node_id 2 for calling a global function with example usage: gram_matrix(v) and returns: tf