Program brian
- 1. Program Brian real x1,x2 external rtbis,func x1=0.1 x2=1 xacc=0.0001 y=rtbis(func,x1,x2,xacc) print*, 'rtbis;', y end function func(x) func=2*x**3+x**2-x-5 end FUNCTION rtbis(func,x1,x2,xacc) INTEGER JMAX REAL rtbis,x1,x2,xacc,func PARAMETER (JMAX=1000) REAL dx,f,fmid,xmid fmid=func(x2) f=func(x1) if(f*fmid.ge.0.) pause if(f.lt.0.)then rtbis=x1 dx=x2-x1 else rtbis=x2 dx=x1-x2
- 2. endif do j=1,JMAX dx=dx*.5 xmid=rtbis+dx fmid=func(xmid) if(fmid.le.0.)rtbis=xmid if(abs(dx).lt.xacc .or. fmid.eq.0.) return enddo pause end