# tensorflow:: ops:: UnsortedSegmentSum

 #include <math_ops.h> 

Computes the sum along segments of a tensor.

## Summary

Read the section on segmentation for an explanation of segments.

Computes a tensor such that $$output[i] = {j...} data[j...]$$ where the sum is over tuples  j...  such that  segment_ids[j...] == i  . Unlike  SegmentSum  ,  segment_ids  need not be sorted and need not cover all values in the full range of valid values.

If the sum is empty for a given segment ID  i  ,  output[i] = 0  . If the given segment ID  i  is negative, the value is dropped and will not be added to the sum of the segment.

 num_segments  should equal the number of distinct segment IDs.

c = tf.constant([[1,2,3,4], [5,6,7,8], [4,3,2,1]])
tf.math.unsorted_segment_sum(c, tf.constant([0, 1, 0]), num_segments=2)
# ==> [[ 5, 5, 5, 5],
#       [5, 6, 7, 8]]


Args:

• scope: A Scope object
• segment_ids: A tensor whose shape is a prefix of  data.shape  .

Returns:

•  Output  : Has same shape as data, except for the first  segment_ids.rank  dimensions, which are replaced with a single dimension which has size  num_segments  .

### Constructors and Destructors

 UnsortedSegmentSum (const :: tensorflow::Scope & scope, :: tensorflow::Input data, :: tensorflow::Input segment_ids, :: tensorflow::Input num_segments) 

### Public attributes

 operation 
 Operation 
 output 
 :: tensorflow::Output 

### Public functions

 node () const 
 ::tensorflow::Node * 
 operator::tensorflow::Input () const 
 
 operator::tensorflow::Output () const 
 

## Public attributes

### operation

Operation operation

### output

::tensorflow::Output output

## Public functions

### UnsortedSegmentSum

 UnsortedSegmentSum(
const ::tensorflow::Scope & scope,
::tensorflow::Input data,
::tensorflow::Input segment_ids,
::tensorflow::Input num_segments
)

### node

::tensorflow::Node * node() const

### operator::tensorflow::Input

 operator::tensorflow::Input() const

### operator::tensorflow::Output

 operator::tensorflow::Output() const
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