tf.compat.v1.pad

Pads a tensor.

tf.compat.v1.pad(
    tensor, paddings, mode='CONSTANT', name=None, constant_values=0
)

This operation pads a tensor according to the paddings you specify. paddings is an integer tensor with shape [n, 2], where n is the rank of tensor. For each dimension D of input, paddings[D, 0] indicates how many values to add before the contents of tensor in that dimension, and paddings[D, 1] indicates how many values to add after the contents of tensor in that dimension. If mode is "REFLECT" then both paddings[D, 0] and paddings[D, 1] must be no greater than tensor.dim_size(D) - 1. If mode is "SYMMETRIC" then both paddings[D, 0] and paddings[D, 1] must be no greater than tensor.dim_size(D).

The padded size of each dimension D of the output is:

paddings[D, 0] + tensor.dim_size(D) + paddings[D, 1]

For example:

t = tf.constant([[1, 2, 3], [4, 5, 6]])
paddings = tf.constant([[1, 1,], [2, 2]])
# 'constant_values' is 0.
# rank of 't' is 2.
tf.pad(t, paddings, "CONSTANT")  # [[0, 0, 0, 0, 0, 0, 0],
                                 #  [0, 0, 1, 2, 3, 0, 0],
                                 #  [0, 0, 4, 5, 6, 0, 0],
                                 #  [0, 0, 0, 0, 0, 0, 0]]

tf.pad(t, paddings, "REFLECT")  # [[6, 5, 4, 5, 6, 5, 4],
                                #  [3, 2, 1, 2, 3, 2, 1],
                                #  [6, 5, 4, 5, 6, 5, 4],
                                #  [3, 2, 1, 2, 3, 2, 1]]

tf.pad(t, paddings, "SYMMETRIC")  # [[2, 1, 1, 2, 3, 3, 2],
                                  #  [2, 1, 1, 2, 3, 3, 2],
                                  #  [5, 4, 4, 5, 6, 6, 5],
                                  #  [5, 4, 4, 5, 6, 6, 5]]

Args
tensor	A Tensor.
paddings	A Tensor of type int32.
mode	One of "CONSTANT", "REFLECT", or "SYMMETRIC" (case-insensitive)
name	A name for the operation (optional).
constant_values	In "CONSTANT" mode, the scalar pad value to use. Must be same type as tensor.

Returns
A Tensor. Has the same type as tensor.

Raises
ValueError	When mode is not one of "CONSTANT", "REFLECT", or "SYMMETRIC".