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piscal/dataassim/math/numrec/f77_sources/ratval.for
T
2016-02-03 18:52:05 +00:00

17 lines
393 B
Fortran

FUNCTION ratval(x,cof,mm,kk)
INTEGER kk,mm
DOUBLE PRECISION ratval,x,cof(mm+kk+1)
INTEGER j
DOUBLE PRECISION sumd,sumn
sumn=cof(mm+1)
do 11 j=mm,1,-1
sumn=sumn*x+cof(j)
11 continue
sumd=0.d0
do 12 j=mm+kk+1,mm+2,-1
sumd=(sumd+cof(j))*x
12 continue
ratval=sumn/(1.d0+sumd)
return
END