zswap Subroutine

public subroutine zswap(n, zx, incx, zy, incy)

NAME

zswap(3f) - [BLAS:COMPLEX16_BLAS_LEVEL1]

SYNOPSIS

 subroutine zswap(n,zx,incx,zy,incy)

   .. Scalar Arguments ..
   integer,intent(in)                 :: incx,incy,n
   ..
   .. Array Arguments ..
   complex(kind=real64),intent(inout) :: zx(*),zy(*)
   ..

DEFINITION

 ZSWAP interchanges two vectors.

OPTIONS

N

       N is INTEGER
      number of elements in input vector(s)

ZX

       ZX is complex(kind=real64) array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX

       INCX is INTEGER
      storage spacing between elements of ZX

ZY

       ZY is complex(kind=real64) array, dimension ( 1 + ( N - 1 )*abs( INCY ) )

INCY

       INCY is INTEGER
      storage spacing between elements of ZY

AUTHORS

  • Univ. of Tennessee
  • Univ. of California Berkeley
  • Univ. of Colorado Denver
  • NAG Ltd.

date:November 2017

FURTHER DETAILS

  jack dongarra, 3/11/78.
  modified 12/3/93, array(1) declarations changed to array(*)

SEE ALSO

Online html documentation available at
http://www.netlib.org/lapack/explore-html/

Arguments

Type IntentOptional Attributes Name
integer, intent(in) :: n
complex(kind=real64), intent(inout) :: zx(*)
integer, intent(in) :: incx
complex(kind=real64), intent(inout) :: zy(*)
integer, intent(in) :: incy

Contents

Variables

Source Code

zswap

Variables

Type Visibility Attributes Name Initial
integer, public :: i
integer, public :: ix
integer, public :: iy
complex(kind=real64), public :: ztemp

Source Code

       subroutine zswap(n,zx,incx,zy,incy)
      implicit none
!
!  -- Reference BLAS level1 routine (version 3.8.0) --
!  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
!  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
!     November 2017
!
!     .. Scalar Arguments ..
      integer,intent(in)                 :: incx,incy,n
!     ..
!     .. Array Arguments ..
      complex(kind=real64),intent(inout) :: zx(*),zy(*)
!     ..
!
!  =====================================================================
!
!     .. Local Scalars ..
      complex(kind=real64) :: ztemp
      integer i,ix,iy
!     ..
      if (n.le.0) return
      if (incx.eq.1 .and. incy.eq.1) then
!
!       code for both increments equal to 1
         do i = 1,n
            ztemp = zx(i)
            zx(i) = zy(i)
            zy(i) = ztemp
         enddo
      else
!
!       code for unequal increments or equal increments not equal
!         to 1
!
         ix = 1
         iy = 1
         if (incx.lt.0) ix = (-n+1)*incx + 1
         if (incy.lt.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
         enddo
      endif

      end subroutine zswap