# tf.math.sign

Returns an element-wise indication of the sign of a number.

### Used in the notebooks

Used in the tutorials

`y = sign(x) = -1 if x < 0; 0 if x == 0; 1 if x > 0`.

For complex numbers, `y = sign(x) = x / |x| if x != 0, otherwise y = 0`.

#### Example usage:

````# real number`
`tf.math.sign([0., 2., -3.])`
`<tf.Tensor: shape=(3,), dtype=float32,`
`numpy=array([ 0.,  1., -1.], dtype=float32)>`
```
````# complex number`
`tf.math.sign([1 + 1j, 0 + 0j])`
`<tf.Tensor: shape=(2,), dtype=complex128,`
`numpy=array([0.70710678+0.70710678j, 0.        +0.j        ])>`
```

`x` A Tensor. Must be one of the following types: bfloat16, half, float32, float64, int32, int64, complex64, complex128.
`name` A name for the operation (optional).

A Tensor. Has the same type as x.

If x is a SparseTensor, returns SparseTensor(x.indices, tf.math.sign(x.values, ...), x.dense_shape).

If `x` is a `SparseTensor`, returns `SparseTensor(x.indices, tf.math.sign(x.values, ...), x.dense_shape)`

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