Adds sparse `updates`

to an existing tensor according to `indices`

.

tf.tensor_scatter_nd_add( tensor, indices, updates, name=None )

This operation creates a new tensor by adding sparse `updates`

to the passed in `tensor`

. This operation is very similar to `tf.scatter_nd_add`

, except that the updates are added onto an existing tensor (as opposed to a variable). If the memory for the existing tensor cannot be re-used, a copy is made and updated.

`indices`

is an integer tensor containing indices into a new tensor of shape `tensor.shape`

. The last dimension of `indices`

can be at most the rank of `tensor.shape`

:

indices.shape[-1] <= tensor.shape.rank

The last dimension of `indices`

corresponds to indices into elements (if `indices.shape[-1] = tensor.shape.rank`

) or slices (if `indices.shape[-1] < tensor.shape.rank`

) along dimension `indices.shape[-1]`

of `tensor.shape`

. `updates`

is a tensor with shape

indices.shape[:-1] + tensor.shape[indices.shape[-1]:]

The simplest form of tensor_scatter_add is to add individual elements to a tensor by index. For example, say we want to add 4 elements in a rank-1 tensor with 8 elements.

In Python, this scatter add operation would look like this:

indices = tf.constant([[4], [3], [1], [7]]) updates = tf.constant([9, 10, 11, 12]) tensor = tf.ones([8], dtype=tf.int32) updated = tf.tensor_scatter_nd_add(tensor, indices, updates) print(updated)

The resulting tensor would look like this:

[1, 12, 1, 11, 10, 1, 1, 13]

We can also, insert entire slices of a higher rank tensor all at once. For example, if we wanted to insert two slices in the first dimension of a rank-3 tensor with two matrices of new values.

In Python, this scatter add operation would look like this:

indices = tf.constant([[0], [2]]) updates = tf.constant([[[5, 5, 5, 5], [6, 6, 6, 6], [7, 7, 7, 7], [8, 8, 8, 8]], [[5, 5, 5, 5], [6, 6, 6, 6], [7, 7, 7, 7], [8, 8, 8, 8]]]) tensor = tf.ones([4, 4, 4],dtype=tf.int32) updated = tf.tensor_scatter_nd_add(tensor, indices, updates) print(updated)

The resulting tensor would look like this:

[[[6, 6, 6, 6], [7, 7, 7, 7], [8, 8, 8, 8], [9, 9, 9, 9]], [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]], [[6, 6, 6, 6], [7, 7, 7, 7], [8, 8, 8, 8], [9, 9, 9, 9]], [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]]

Note that on CPU, if an out of bound index is found, an error is returned. On GPU, if an out of bound index is found, the index is ignored.

Args | |
---|---|

`tensor` | A `Tensor` . Tensor to copy/update. |

`indices` | A `Tensor` . Must be one of the following types: `int32` , `int64` . Index tensor. |

`updates` | A `Tensor` . Must have the same type as `tensor` . Updates to scatter into output. |

`name` | A name for the operation (optional). |

Returns | |
---|---|

A `Tensor` . Has the same type as `tensor` . |

© 2020 The TensorFlow Authors. All rights reserved.

Licensed under the Creative Commons Attribution License 3.0.

Code samples licensed under the Apache 2.0 License.

https://www.tensorflow.org/versions/r2.4/api_docs/python/tf/tensor_scatter_nd_add