Gamma Function Division
Date: 12/20/2005 at 08:53:05 From: Vinicius Subject: Gamma Function Division Is there any formula for Gamma(n)/Gamma(m) for n and m integer values >= 1 and m < n? Gamma(n) can be too big, and I need a result with an |absolute error| <= 1. Stirling's Approximation doesn't apply. I already have the Gamma(n) formula. But I need some formula to get Gamma(n)/Gamma(m) directly without two integrals. I suppose I could write a computer program to do the calculation with exact value.
Date: 12/20/2005 at 10:03:32 From: Doctor George Subject: Re: Gamma Function Division Hi Vinicius, Thanks for writing to Doctor Math. You should consider using logarithms and computing ln(gamma(n)/gamma(m)) = ln(gamma(n)) - ln(gamma(m)) The logarithm of the gamma function is sometimes called the log-gamma function and it has been studied extensively. See this link: Log Gamma Function http://mathworld.wolfram.com/LogGammaFunction.html Here is one place where you can find code for the log-gamma function: http://www.moshier.net/#Cephes Does that make sense? Write again if you need more help. - Doctor George, The Math Forum http://mathforum.org/dr.math/
Date: 12/21/2005 at 11:16:43 From: Vinicius Subject: Thank you (Gamma Function Division) That makes great sense. Thanks!
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