subroutine cscal(n,ca,cx,incx)
c
c     scales a vector by a constant.
c     jack dongarra, linpack,  3/11/78.
c
      complex ca,cx(1)
      integer i,incx,n,nincx
c
      if(n.le.0)return
      if(incx.eq.1)go to 20
c
c        code for increment not equal to 1
c
      nincx = n*incx
      do 10 i = 1,nincx,incx
        cx(i) = ca*cx(i)
   10 continue
      return
c
c        code for increment equal to 1
c
   20 do 30 i = 1,n
        cx(i) = ca*cx(i)
   30 continue
      return
      end

.