3.316. __nv_tgamma

double @__nv_tgamma(double %x)

Calculate the gamma function of the input argument.

Calculate the gamma function of the input argument x, namely the value of \(\int_{0}^{\infty} e^{-t}t^{x-1}dt\).

Note

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

Returns

• __nv_tgamma( \(\pm 0\) ) returns \(\pm \infty\).

• __nv_tgamma(2) returns +0.

• __nv_tgamma(x) returns \(\pm \infty\) if the correctly calculated value is outside the double floating point range.

• __nv_tgamma(x) returns NaN if x < 0.

• __nv_tgamma( \(-\infty\) ) returns NaN.

• __nv_tgamma( \(+\infty\) ) returns \(+\infty\).