scipy.special.betaln#
- scipy.special.betaln(a, b, out=None) = <ufunc 'betaln'>#
Natural logarithm of absolute value of beta function.
Computes
ln(abs(beta(a, b)))
.- Parameters:
- a, barray_like
Positive, real-valued parameters
- outndarray, optional
Optional output array for function values
- Returns:
- scalar or ndarray
Value of the betaln function
See also
Examples
>>> import numpy as np >>> from scipy.special import betaln, beta
Verify that, for moderate values of
a
andb
,betaln(a, b)
is the same aslog(beta(a, b))
:>>> betaln(3, 4) -4.0943445622221
>>> np.log(beta(3, 4)) -4.0943445622221
In the following
beta(a, b)
underflows to 0, so we can’t compute the logarithm of the actual value.>>> a = 400 >>> b = 900 >>> beta(a, b) 0.0
We can compute the logarithm of
beta(a, b)
by usingbetaln
:>>> betaln(a, b) -804.3069951764146