Fortran 95 source code to compute inner-product of vetors(Ver.2).

inner_product_2.f95

!****************************************************
! ベクトルの内積を計算(Ver.2)
!
! date          name            version
! 2018.08.20    mk-mode.com     1.00 新規作成
!
! Copyright(C) 2018 mk-mode.com All Rights Reserved.
!****************************************************
!
program inner_product_2
  implicit none
  integer, parameter :: n = 3
  real(8) :: x(n) = (/ 1, 2, 3 /)
  real(8) :: y(n) = (/ 4, 5, 6 /)

  write (*,*) iprod(n, x, y)
  write (*,*) dot_product(x, y)  ! 組み込み関数で検算

  stop
contains
  ! 内積計算
  !
  ! :param(in)  integer(4) dim
  ! :param(in)  real(8) x(dim)
  ! :param(in)  real(8) y(dim)
  ! :return     real(8)
  real(8) function iprod(dim, x, y)
    implicit none
    integer, intent(IN) :: dim
    real(8), intent(IN) :: x(dim), y(dim)
    integer :: i

    iprod = 0
    do i = 1, dim
      iprod = iprod + x(i) * y(i)
    enddo
    return
  end function iprod
end program inner_product_2