<br />

|---|
| [![](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#L4203-L4245) |

Computes log sigmoid of `x` element-wise.

#### View aliases


**Compat aliases for migration**

See
[Migration guide](https://www.tensorflow.org/guide/migrate) for
more details.

[`tf.compat.v1.log_sigmoid`](https://www.tensorflow.org/api_docs/python/tf/math/log_sigmoid)

<br />

    tf.math.log_sigmoid(
        x, name=None
    )

Specifically, `y = log(1 / (1 + exp(-x)))`. For numerical stability,
we use `y = -tf.nn.softplus(-x)`.

<br />

<br />

<br />

| ## Args ||
|---|---|
| `x` | A Tensor with type `float32` or `float64`. |
| `name` | A name for the operation (optional). |

<br />

<br />

<br />

<br />

| ## Returns ||
|---|---|
| A Tensor with the same type as `x`. ||

<br />

#### Usage Example:

If a positive number is large, then its log_sigmoid will approach to 0 since
the formula will be `y = log( <large_num> / (1 + <large_num>) )` which
approximates to `log (1)` which is 0.

    x = tf.constant([0.0, 1.0, 50.0, 100.0])
    tf.math.log_sigmoid(x)
    <tf.Tensor: shape=(4,), dtype=float32, numpy=
    array([-6.9314718e-01, -3.1326169e-01, -1.9287499e-22, -0.0000000e+00],
          dtype=float32)>

If a negative number is large, its log_sigmoid will approach to the number
itself since the formula will be `y = log( 1 / (1 + <large_num>) )` which is
`log (1) - log ( (1 + <large_num>) )` which approximates to `- <large_num>`
that is the number itself.

    x = tf.constant([-100.0, -50.0, -1.0, 0.0])
    tf.math.log_sigmoid(x)
    <tf.Tensor: shape=(4,), dtype=float32, numpy=
    array([-100.       ,  -50.       ,   -1.3132616,   -0.6931472],
          dtype=float32)>