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

34 lines
894 B
Fortran

FUNCTION amotsa(p,y,psum,mp,np,ndim,pb,yb,funk,ihi,yhi,fac)
INTEGER ihi,mp,ndim,np,NMAX
REAL amotsa,fac,yb,yhi,p(mp,np),pb(np),psum(np),y(mp),funk
PARAMETER (NMAX=200)
EXTERNAL funk
CU USES funk,ran1
INTEGER idum,j
REAL fac1,fac2,tt,yflu,ytry,ptry(NMAX),ran1
COMMON /ambsa/ tt,idum
fac1=(1.-fac)/ndim
fac2=fac1-fac
do 11 j=1,ndim
ptry(j)=psum(j)*fac1-p(ihi,j)*fac2
11 continue
ytry=funk(ptry)
if (ytry.le.yb) then
do 12 j=1,ndim
pb(j)=ptry(j)
12 continue
yb=ytry
endif
yflu=ytry-tt*log(ran1(idum))
if (yflu.lt.yhi) then
y(ihi)=ytry
yhi=yflu
do 13 j=1,ndim
psum(j)=psum(j)-p(ihi,j)+ptry(j)
p(ihi,j)=ptry(j)
13 continue
endif
amotsa=yflu
return
END