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/agauss.f | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 math/bevington/agauss.f (limited to 'math/bevington/agauss.f') diff --git a/math/bevington/agauss.f b/math/bevington/agauss.f new file mode 100644 index 00000000..6aefc503 --- /dev/null +++ b/math/bevington/agauss.f @@ -0,0 +1,40 @@ +c function agauss.f +c +c source +c Bevington, page 48. +c +c purpose +c evaluate integral of gaussian probability function +c +c usage +c result = agauss (x, averag, sigma) +c +c description of parameters +c x - limit for integral +c averag - mean of distribution +c sigma - standard deviation of distribution +c integration range is averag +/- z*sigma +c where z = abs(x-averag)/sigma +c +c subroutines and function subprograms required +c none +c + function agauss (x,averag,sigma) + double precision z,y2,term,sum,denom +11 z=abs(x-averag)/sigma + agauss=0. + if (z) 42,42,21 +21 term=0.7071067812*z +22 sum=term + y2=(z**2)/2. + denom=1. +c +c accumulate sums of terms +c +31 denom=denom+2. +32 term=term*(y2*2./denom) +33 sum=sum+term + if (term/sum-1.e-10) 41,41,31 +41 agauss=1.128379167*sum*dexp(-y2) +42 return + end -- cgit