stdlib_zswap Subroutine

     pure subroutine stdlib_zswap(n,zx,incx,zy,incy)
     !! ZSWAP interchanges two vectors.
        ! -- reference blas level1 routine --
        ! -- reference blas is a software package provided by univ. of tennessee,    --
        ! -- univ. of california berkeley, univ. of colorado denver and nag ltd..--
           ! Scalar Arguments 
           integer(ilp), intent(in) :: incx, incy, n
           ! Array Arguments 
           complex(dp), intent(inout) :: zx(*), zy(*)
        ! =====================================================================
           ! Local Scalars 
           complex(dp) :: ztemp
           integer(ilp) :: i, ix, iy
           if (n<=0) return
           if (incx==1 .and. incy==1) then
             ! code for both increments equal to 1
              do i = 1,n
                 ztemp = zx(i)
                 zx(i) = zy(i)
                 zy(i) = ztemp
              end do
           else
             ! code for unequal increments or equal increments not equal
               ! to 1
              ix = 1
              iy = 1
              if (incx<0) ix = (-n+1)*incx + 1
              if (incy<0) iy = (-n+1)*incy + 1
              do i = 1,n
                 ztemp = zx(ix)
                 zx(ix) = zy(iy)
                 zy(iy) = ztemp
                 ix = ix + incx
                 iy = iy + incy
              end do
           end if
           return
     end subroutine stdlib_zswap