subroutine  zscalf(n,za,zx,incx)

c

c     scales a vector by a constant.

c     jack dongarra, 3/11/78.

c     modified 3/93 to return if incx .le. 0.

c     modified 12/3/93, array(1) declarations changed to array(*)

c

      double complex za,zx(*)

      integer i,incx,ix,n

c

      if( n.le.0 .or. incx.le.0 )return

      if(incx.eq.1)go to 20

c

c        code for increment not equal to 1

c

      ix = 1

      do 10 i = 1,n

        zx(ix) = za*zx(ix)

        ix = ix + incx

   10 continue

      return

c

c        code for increment equal to 1

c

   20 do 30 i = 1,n

        zx(i) = za*zx(i)

   30 continue

      return

      end