SUBROUTINE banbks(a,n,m1,m2,np,mp,al,mpl,indx,b)
      INTEGER m1,m2,mp,mpl,n,np,indx(n)
      REAL a(np,mp),al(np,mpl),b(n)
      INTEGER i,k,l,mm
      REAL dum
      mm=m1+m2+1
      if(mm.gt.mp.or.m1.gt.mpl.or.n.gt.np) pause 'bad args in banbks'
      l=m1
      do 12 k=1,n
        i=indx(k)
        if(i.ne.k)then
          dum=b(k)
          b(k)=b(i)
          b(i)=dum
        endif
        if(l.lt.n)l=l+1
        do 11 i=k+1,l
          b(i)=b(i)-al(k,i-k)*b(k)
11      continue
12    continue
      l=1
      do 14 i=n,1,-1
        dum=b(i)
        do 13 k=2,l
          dum=dum-a(i,k)*b(k+i-1)
13      continue
        b(i)=dum/a(i,1)
        if(l.lt.mm) l=l+1
14    continue
      return
      END
C  (C) Copr. 1986-92 Numerical Recipes Software .