nlcpy.logaddexp2

nlcpy.logaddexp2 = <ufunc 'nlcpy_logaddexp2'>

Computes the element-wise base-2 logarithm of 2^{x1} + 2^{x2}.

Parameters
x1, x2array_like

Input arrays or scalars. If x1.shape != x2.shape, they must be broadcastable to a common shape (which becomes the shape of the output).

outndarray or 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.

wherearray_like, optional

This condition is broadcast over the input. At locations where the condition is True, the out array will be set to the ufunc result. Elsewhere, the out array will retain its original value. Note that if an uninitialized out array is created via the default out=None, locations within it where the condition is False will remain uninitialized.

**kwargs

For other keyword-only arguments, see the section Optional Keyword Arguments.

Returns
logaddexp2ndarray

An ndarray, containing log_2(2^{x1} + 2^{x2}) for each element. If x1 and x2 are both scalars, this function returns the result as a 0-dimension ndarray.

See also

logaddexp

Computes the element-wise natural logarithm of exp(x1) + exp(x2).

Examples

>>> import nlcpy as vp
>>> prob1 = vp.log2(1e-50)
>>> prob2 = vp.log2(2.5e-50)
>>> prob12 = vp.logaddexp2(prob1, prob2)
>>> prob12 
array(-164.28904982)
>>> 2**prob12 
array(3.5e-50)