# megengine.functional.log¶

log(x)[源代码]

Element-wise $$\operatorname{log}(x)$$ function.

Calculates an approximation to the natural (base $$e$$) logarithm for each element $$x_i$$ of the input tensor $$x$$.

This function has domain [+0, +infinity] and codomain [-infinity, +infinity].

x – input tensor. Should have a floating-point data type.

a tensor containing the evaluated natural logarithm result for each element in $$x$$. The returned tensor must have a floating-point data type determined by 类型提升规则.

Special cases

For floating-point operands,

• If $$x_i$$ is NaN, the result is NaN.

• If $$x_i$$ is less than 0, the result is NaN.

• If $$x_i$$ is either +0 or -0, the result is -infinity.

• If $$x_i$$ is 1, the result is +0.

• If $$x_i$$ is +infinity, the result is +infinity.

>>> F.log([1, F.exp(1)])
Tensor([0. 1.], device=xpux:0)