LGamma

LGamma(X)

Returns the Log Gamma function of «X». Without numeric overflow, this function is exactly equivalent to Ln(GammaFn(X)). Because the gamma function grows so rapidly, it is often much more convenient to use LGamma() to avoid numeric overflow.

LogBetaFn(x)

To compute Ln(BetaFn(a,b)), you should instead use

LGamma(a) + LGamma(b) - LGamma(a+b)

which is less susceptible to numeric underflow for really large values of a and b.

See Also

• GammaFn
• Factorial
• Ln -- natural log
• BetaFn