SUBROUTINE mnbrak(ax,bx,cx,fa,fb,fc,func) REAL ax,bx,cx,fa,fb,fc,func,GOLD,GLIMIT,TINY EXTERNAL func PARAMETER (GOLD=1.618034, GLIMIT=100., TINY=1.e-20) REAL dum,fu,q,r,u,ulim fa=func(ax) fb=func(bx) if(fb.gt.fa)then dum=ax ax=bx bx=dum dum=fb fb=fa fa=dum endif cx=bx+GOLD*(bx-ax) fc=func(cx) 1 if(fb.ge.fc)then r=(bx-ax)*(fb-fc) q=(bx-cx)*(fb-fa) u=bx-((bx-cx)*q-(bx-ax)*r)/(2.*sign(max(abs(q-r),TINY),q-r)) ulim=bx+GLIMIT*(cx-bx) if((bx-u)*(u-cx).gt.0.)then fu=func(u) if(fu.lt.fc)then ax=bx fa=fb bx=u fb=fu return else if(fu.gt.fb)then cx=u fc=fu return endif u=cx+GOLD*(cx-bx) fu=func(u) else if((cx-u)*(u-ulim).gt.0.)then fu=func(u) if(fu.lt.fc)then bx=cx cx=u u=cx+GOLD*(cx-bx) fb=fc fc=fu fu=func(u) endif else if((u-ulim)*(ulim-cx).ge.0.)then u=ulim fu=func(u) else u=cx+GOLD*(cx-bx) fu=func(u) endif ax=bx bx=cx cx=u fa=fb fb=fc fc=fu goto 1 endif return END C (C) Copr. 1986-92 Numerical Recipes Software .