eigsrt.for

Numerical Recipes一书中例子的源码所用到的函数集,William H. Press 和 Saul A. Teukolsky 所著

      SUBROUTINE eigsrt(d,v,n,np)
      INTEGER n,np
      REAL d(np),v(np,np)
      INTEGER i,j,k
      REAL p
      do 13 i=1,n-1
        k=i
        p=d(i)
        do 11 j=i+1,n
          if(d(j).ge.p)then
            k=j
            p=d(j)
          endif
11      continue
        if(k.ne.i)then
          d(k)=d(i)
          d(i)=p
          do 12 j=1,n
            p=v(j,i)
            v(j,i)=v(j,k)
            v(j,k)=p
12        continue
        endif
13    continue
      return
      END