module swaps
!---------------------------------------------
! SWAP Subtoutines
!---------------------------------------------
! HISTORY
!  2020/10/29 [v1.0  ] <new> author = Koji KOBAYASHI
!  2020/11/ 4 [v1.0.1] <comment> usage
!---------------------------------------------
! REQUIREMENTS
!  None (stand alone)
!---------------------------------------------
! USAGE
!  use swaps
!  integer            :: i,j
!  integer            :: ivec(3),jvec(3)
!  integer            :: iMat(2,2),jMat(2,2)
!  real(kind(0d0))    :: a,b
!  real(kind(0d0))    :: avec(3),bvec(3)
!  real(kind(0d0))    :: aMat(2,2),bMat(2,2)
!  complex(kind(0d0)) :: za,zb
!  complex(kind(0d0)) :: zavec(3),zbvec(3)
!  complex(kind(0d0)) :: zaMat(2,2),zbMat(2,2)
!    call swap(i,j)
!    call swap(ivec,jvec)
!    call swap(iMat,jMat)
!    call swap(a,b)
!    call swap(avec,bvec)
!    call swap(aMat,bMat)
!    call swap(za,zb)
!    call swap(zavec,zbvec)
!    call swap(zaMat,zbMat)
!---------------------------------------------
 implicit none
 private

 INTERFACE swap
    module procedure swap_i,swap_d,swap_z
 end INTERFACE

 public :: swap

CONTAINS
!---------------------------------------------
! integer
!---------------------------------------------
 pure elemental subroutine swap_i(a,b)
  integer, intent(inout) :: a, b
  integer :: temp
     temp = a ; a = b ; b = temp
 end subroutine
!---------------------------------------------

!---------------------------------------------
! double
!---------------------------------------------
 pure elemental subroutine swap_d(a,b)
  real(kind(0d0)), intent(inout) :: a, b
  real(kind(0d0)) :: temp
     temp = a ; a = b ; b = temp
 end subroutine
!---------------------------------------------

!---------------------------------------------
! double complex
!---------------------------------------------
 pure elemental subroutine swap_z(a,b)
  complex(kind(0d0)), intent(inout) :: a, b
  complex(kind(0d0)) :: temp
     temp = a ; a = b ; b = temp
 end subroutine
!---------------------------------------------

end module swaps