zaxpy.f

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      subroutine zaxpy(n,za,zx,incx,zy,incy)
c
c     constant times a vector plus a vector.
c     jack dongarra, 3/11/78.
c     modified 12/3/93, array(1) declarations changed to array(*)
c
      double complex zx(*),zy(*),za
      integer i,incx,incy,ix,iy,n
      double precision dcabs1
      if(n.le.0)return
      if (dcabs1(za) .eq. 0.0d0) return
      if (incx.eq.1.and.incy.eq.1)go to 20
c
c        code for unequal increments or equal increments
c          not equal to 1
c
      ix = 1
      iy = 1
      if(incx.lt.0)ix = (-n+1)*incx + 1
      if(incy.lt.0)iy = (-n+1)*incy + 1
      do 10 i = 1,n
        zy(iy) = zy(iy) + za*zx(ix)
        ix = ix + incx
        iy = iy + incy
   10 continue
      return
c
c        code for both increments equal to 1
c
   20 do 30 i = 1,n
        zy(i) = zy(i) + za*zx(i)
   30 continue
      return
      end