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| [![](https://www.tensorflow.org/images/GitHub-Mark-32px.png) View source on GitHub](https://github.com/tensorflow/tensorflow/blob/v2.13.1/tensorflow/python/ops/sparse_ops.py#L1470-L1546) |

Computes [`tf.sparse.add`](https://www.tensorflow.org/versions/r2.13/api_docs/python/tf/sparse/add) of elements across dimensions of a SparseTensor.

    tf.sparse.reduce_sum(
        sp_input, axis=None, keepdims=None, output_is_sparse=False, name=None
    )

This is the reduction operation for the elementwise [`tf.sparse.add`](https://www.tensorflow.org/versions/r2.13/api_docs/python/tf/sparse/add) op.

This Op takes a SparseTensor and is the sparse counterpart to
[`tf.reduce_sum()`](https://www.tensorflow.org/versions/r2.13/api_docs/python/tf/math/reduce_sum). In particular, this Op also returns a dense `Tensor`
if `output_is_sparse` is `False`, or a `SparseTensor` if `output_is_sparse`
is `True`.

> [!NOTE]
> **Note:** if `output_is_sparse` is True, a gradient is not defined for this function, so it can't be used in training models that need gradient descent.

Reduces `sp_input` along the dimensions given in `axis`. Unless `keepdims` is
true, the rank of the tensor is reduced by 1 for each entry in `axis`. If
`keepdims` is true, the reduced dimensions are retained with length 1.

If `axis` has no entries, all dimensions are reduced, and a tensor
with a single element is returned. Additionally, the axes can be negative,
similar to the indexing rules in Python.

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| ## For example ||
|---|---|
| <br /> # 'x' represents \[\[1, ?, 1\] # \[?, 1, ?\]\] # where ? is implicitly-zero. x = tf.sparse.SparseTensor([[0, 0], [0, 2], [1, 1]], [1, 1, 1], [2, 3]) tf.sparse.reduce_sum(x) <tf.Tensor: shape=(), dtype=int32, numpy=3> tf.sparse.reduce_sum(x, 0) <tf.Tensor: shape=(3,), dtype=int32, numpy=array([1, 1, 1], dtype=int32)> tf.sparse.reduce_sum(x, 1)  # Can also use -1 as the axis <tf.Tensor: shape=(2,), dtype=int32, numpy=array([2, 1], dtype=int32)> tf.sparse.reduce_sum(x, 1, keepdims=True) <tf.Tensor: shape=(2, 1), dtype=int32, numpy= array([[2], [1]], dtype=int32)> tf.sparse.reduce_sum(x, [0, 1]) <tf.Tensor: shape=(), dtype=int32, numpy=3> <br /> ||

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| ## Args ||
|---|---|
| `sp_input` | The SparseTensor to reduce. Should have numeric type. |
| `axis` | The dimensions to reduce; list or scalar. If `None` (the default), reduces all dimensions. |
| `keepdims` | If true, retain reduced dimensions with length 1. |
| `output_is_sparse` | If true, returns a `SparseTensor` instead of a dense `Tensor` (the default). |
| `name` | A name for the operation (optional). |

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| ## Returns ||
|---|---|
| The reduced Tensor or the reduced SparseTensor if `output_is_sparse` is True. ||

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