From 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 Mon Sep 17 00:00:00 2001 From: Joe Hunkeler Date: Tue, 11 Aug 2015 16:51:37 -0400 Subject: Repatch (from linux) of OSX IRAF --- math/bevington/factor.f | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 math/bevington/factor.f (limited to 'math/bevington/factor.f') diff --git a/math/bevington/factor.f b/math/bevington/factor.f new file mode 100644 index 00000000..23b23307 --- /dev/null +++ b/math/bevington/factor.f @@ -0,0 +1,39 @@ +c function factor.f +c +c source +c Bevington, page 32. +c +c purpose +c calculates factorial function for integers +c +c usage +c result = factor (n) +c +c description of parameters +c n - integer argument +c +c subroutines and function subprograms required +c none +c + function factor (n) + double precision fi,sum +11 factor=1. + if (n-1) 40,40,13 +13 if (n-10) 21,21,31 +c +c n less than 11 +c +21 do 23 i=2,n + fi=i +23 factor=factor*fi + goto 40 +c +c n greater than 10 +c +31 sum=0. + do 34 i=11,n + fi=i +34 sum=sum+dlog(fi) +35 factor=3628800.*dexp(sum) +40 return + end -- cgit