in tfops.py [0:0]
def upsample2d_nearest_neighbour(x):
shape = x.get_shape()
n_batch = int(shape[0])
height = int(shape[1])
width = int(shape[2])
n_channels = int(shape[3])
x = tf.reshape(x, (n_batch, height, 1, width, 1, n_channels))
x = tf.concat(2, [x, x])
x = tf.concat(4, [x, x])
x = tf.reshape(x, (n_batch, height*2, width*2, n_channels))
return x