mxnet.np.log1p¶
-
log1p
(x, out=None, **kwargs)¶ Return the natural logarithm of one plus the input array, element-wise. Calculates
log(1 + x)
.- Parameters
x (ndarray or scalar) – Input array.
out (ndarray or None) – A location into which the result is stored. If provided, it must have a shape that the inputs fill into. If not provided or None, a freshly-allocated array is returned. The dtype of the output and input must be the same.
- Returns
y – Natural logarithm of 1 + x, element-wise. This is a scalar if x is a scalar.
- Return type
ndarray or scalar
Notes
For real-valued input, log1p is accurate also for x so small that 1 + x == 1 in floating-point accuracy. Logarithm is a multivalued function: for each x there is an infinite number of z such that exp(z) = 1 + x. The convention is to return the z whose imaginary part lies in [-pi, pi]. For real-valued input data types, log1p 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. cannot support complex-valued input.Examples
>>> np.log1p(1e-99) 1e-99 >>> a = np.array([3, 4, 5]) >>> np.log1p(a) array([1.3862944, 1.609438 , 1.7917595])