libdevice User's Guide :: CUDA Toolkit Documentation

3.201. __nv_lgamma

Prototype:

double @__nv_lgamma(double %x)

Description:

Calculate the natural logarithm of the absolute value of the gamma function of the input argument x, namely the value of $\log_{e} (\int_{0}^{\infty} e^{- t} t^{x - 1} d t)$

Returns:

__nv_lgamma(1) returns +0.
__nv_lgamma(2) returns +0.
__nv_lgamma(x) returns $\pm \infty$ if the correctly calculated value is outside the double floating point range.
__nv_lgamma(x) returns $+ \infty$ if x $\leq$ 0.
__nv_lgamma( $- \infty$ ) returns $- \infty$ .
__nv_lgamma( $+ \infty$ ) returns $+ \infty$ .

Note:

For accuracy information see the CUDA C++ Programming Guide, Mathematical Functions Appendix, Double-Precision Floating-Point Functions section.

Library Availability:

Compute 2.0: Yes

Compute 3.0: Yes

Compute 3.5: Yes