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|---|
| [![](https://www.tensorflow.org/images/GitHub-Mark-32px.png) View source on GitHub](https://github.com/tensorflow/tensorflow/blob/v2.21.0/tensorflow/python/ops/math_ops.py#L2631-L2691) |

Computes the variance of elements across dimensions of a tensor.

    tf.math.reduce_variance(
        input_tensor, axis=None, keepdims=False, name=None
    )

Reduces `input_tensor` along the dimensions given in `axis`.
Unless `keepdims` is true, the rank of the tensor is reduced by 1 for each
of the entries in `axis`, which must be unique. If `keepdims` is true, the
reduced dimensions are retained with length 1.

If `axis` is None, all dimensions are reduced, and a
tensor with a single element is returned.

#### For example:

    x = tf.constant([[1., 2.], [3., 4.]])
    tf.math.reduce_variance(x)
    <tf.Tensor: shape=(), dtype=float32, numpy=1.25>
    tf.math.reduce_variance(x, 0)
    <tf.Tensor: shape=(2,), dtype=float32, numpy=array([1., 1.], ...)>
    tf.math.reduce_variance(x, 1)
    <tf.Tensor: shape=(2,), dtype=float32, numpy=array([0.25, 0.25], ...)>

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| ## Args ||
|---|---|
| `input_tensor` | The tensor to reduce. Should have real or complex type. |
| `axis` | The dimensions to reduce. If `None` (the default), reduces all dimensions. Must be in the range `[-rank(input_tensor), rank(input_tensor))`. |
| `keepdims` | If true, retains reduced dimensions with length 1. |
| `name` | A name scope for the associated operations (optional). |

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| ## Returns ||
|---|---|
| The reduced tensor, of the same dtype as the input_tensor. Note, for `complex64` or `complex128` input, the returned `Tensor` will be of type `float32` or `float64`, respectively. ||

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## numpy compatibility

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Equivalent to np.var

Please note `np.var` has a `dtype` parameter that could be used to specify the
output type. By default this is `dtype=float64`. On the other hand,
[`tf.math.reduce_variance`](https://www.tensorflow.org/api_docs/python/tf/math/reduce_variance) has aggressive type inference from `input_tensor`.

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