flopscope.numpy.log10
fnp.log10(*args, **kwargs)[flopscope source][numpy source]
Return the base 10 logarithm of the input array, element-wise.
Adapted from NumPy docs np.log10
Element-wise base-10 logarithm.
Parameters
- x:array_like
Input values.
- out:ndarray, None, or tuple of ndarray 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 array is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.
- where:array_like, optional
This condition is broadcast over the input. At locations where the condition is True, the
outarray will be set to the ufunc result. Elsewhere, theoutarray will retain its original value. Note that if an uninitializedoutarray is created via the defaultout=None, locations within it where the condition is False will remain uninitialized.- **kwargs
For other keyword-only arguments, see the ufunc docs.
Returns
- y:ndarray
The logarithm to the base 10 of
x, element-wise. NaNs are returned where x is negative. This is a scalar ifxis a scalar.
See also
- emath.log10
Notes
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.
In the cases where the input has a negative real part and a very small
negative complex part (approaching 0), the result is so close to -pi
that it evaluates to exactly -pi.
References
1
M. Abramowitz and I.A. Stegun, "Handbook of Mathematical Functions",
10th printing, 1964, pp. 67.
https://personal.math.ubc.ca/~cbm/aands/page_67.htm2
Wikipedia, "Logarithm". https://en.wikipedia.org/wiki/LogarithmExamples
>>> import flopscope.numpy as fnp
>>> flops.log10([1e-15, -3.])
array([-15., nan])