mars.tensor.log10

mars.tensor.log10(x, out=None, where=None, **kwargs)[source]

Return the base 10 logarithm of the input tensor, element-wise.

x : array_like
Input values.
out : Tensor, None, or tuple of tensor and None, optional
A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshly-allocated tensor is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.
where : array_like, optional
Values of True indicate to calculate the ufunc at that position, values of False indicate to leave the value in the output alone.

**kwargs

y : Tensor
The logarithm to the base 10 of x, element-wise. NaNs are returned where x is negative.

Logarithm is a multivalued function: for each x there is an infinite number of z such that 10**z = x. The convention is to return the z whose imaginary part lies in [-pi, pi].

For real-valued input data types, log10 always returns real output. For each value that cannot be expressed as a real number or infinity, it yields nan and sets the invalid floating point error flag.

For complex-valued input, log10 is a complex analytical function that has a branch cut [-inf, 0] and is continuous from above on it. log10 handles the floating-point negative zero as an infinitesimal negative number, conforming to the C99 standard.

[1]M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp. 67. http://www.math.sfu.ca/~cbm/aands/
[2]Wikipedia, “Logarithm”. http://en.wikipedia.org/wiki/Logarithm
>>> import mars.tensor as mt
>>> mt.log10([1e-15, -3.]).execute()
array([-15.,  NaN])