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Computes the sum along sparse segments of a tensor.

tf.sparse.segment_sum( data, indices, segment_ids, name=None, num_segments=None )

Read the section on segmentation for an explanation of segments.

Like `tf.math.segment_sum`

, but `segment_ids`

can have rank less than `data`

's first dimension, selecting a subset of dimension 0, specified by `indices`

. `segment_ids`

is allowed to have missing ids, in which case the output will be zeros at those indices. In those cases `num_segments`

is used to determine the size of the output.

c = tf.constant([[1,2,3,4], [-1,-2,-3,-4], [5,6,7,8]]) # Select two rows, one segment. tf.sparse.segment_sum(c, tf.constant([0, 1]), tf.constant([0, 0])) # => [[0 0 0 0]] # Select two rows, two segment. tf.sparse.segment_sum(c, tf.constant([0, 1]), tf.constant([0, 1])) # => [[ 1 2 3 4] # [-1 -2 -3 -4]] # With missing segment ids. tf.sparse.segment_sum(c, tf.constant([0, 1]), tf.constant([0, 2]), num_segments=4) # => [[ 1 2 3 4] # [ 0 0 0 0] # [-1 -2 -3 -4] # [ 0 0 0 0]] # Select all rows, two segments. tf.sparse.segment_sum(c, tf.constant([0, 1, 2]), tf.constant([0, 0, 1])) # => [[0 0 0 0] # [5 6 7 8]] # Which is equivalent to: tf.math.segment_sum(c, tf.constant([0, 0, 1]))

Args | |
---|---|

`data` | A `Tensor` with data that will be assembled in the output. |

`indices` | A 1-D `Tensor` with indices into `data` . Has same rank as `segment_ids` . |

`segment_ids` | A 1-D `Tensor` with indices into the output `Tensor` . Values should be sorted and can be repeated. |

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

`num_segments` | An optional int32 scalar. Indicates the size of the output `Tensor` . |

Returns | |
---|---|

A `tensor` of the shape as data, except for dimension 0 which has size `k` , the number of segments specified via `num_segments` or inferred for the last element in `segments_ids` . |

© 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/r1.15/api_docs/python/tf/sparse/segment_sum