program index_1d

!     nxp=75
!     nyp=55
!     nzp=35
!     n_var=4

      nxp=30
      nyp=15
      nzp=20
      n_var=7

      ii=1
      jj=7
      ll=5

      i1d=0
      ind_1d=0

      i1d=nxp*nyp*nzp*(n_var-1)

           do l=1,nzp
            do j=1,nyp
             do i=1,nxp
      i1d=i1d+1
      if(i.eq.ii.and.j.eq.jj.and.l.eq.ll) then
      ind_1d=i1d
      go to 200
      endif
             end do
            end do
           end do
  200 continue

      write(*,*) " nxp*nyp*nzp=",nxp*nyp*nzp
      write(*,*) " ind_1d=",ind_1d

      ind_1d=nxp*nyp*(ll-1)+nxp*(jj-1)+ii+nxp*nyp*nzp*(n_var-1)
      write(*,*) " ind_1d=",ind_1d

      end program index_1d