viz_plot Subroutine

subroutine viz_plot(val,nx,ny,max)
real, intent(in)          :: val(:,:)
integer, intent(in)       :: nx,ny
real, intent(in),optional :: max
integer                   :: i, j, k, l, m, n, dx, dy
real                      :: vmax, scalef, tmp

    ! set blocksize for averaging
    dx = nx / cols
    if (dx < 1) dx = 1
    dy = ny / rows
    if (dy < 1) dy = 1

    ! set or determine scaling factor for data points
    vmax=1.0e-30
    if (present(max)) then
       vmax = abs(max)
    else
       ! find absolute maximum value for scaling
       do j=1,rows
          do i=1,cols
             ! average over cells
             tmp = 0.0
             n = 0
             do k=(j-1)*dy+1,j*dy
                do l=(i-1)*dx+1,i*dx
                   tmp = tmp + val(l,k)
                   n = n + 1
                enddo
             enddo

             tmp = ABS(tmp)/REAL(n)
             if (vmax < tmp) vmax = tmp
          enddo
       enddo
    endif
    scalef = real(maxplot)/vmax

    ! now plot
    do j=1,rows
        call viz_pos(1,j)
        do i=1,cols
            ! average over cells
            tmp = 0.0
            n = 0
            do k=(j-1)*dy+1,j*dy
                do l=(i-1)*dx+1,i*dx
                    tmp = tmp + val(l,k)
                    n = n + 1
                enddo
            enddo
            ! convert absolute value into character
            m = int(scalef*abs(tmp)/real(n)+0.5)
            if (m > maxplot) m = 10
            if (tmp < 0.0) then
                if (m > 5) then
                    call viz_put(cli//'36m'//plot(m))
                else
                    call viz_put(cli//'34m'//plot(m))
                endif
            else
                if (m > 5) then
                    call viz_put(cli//'31m'//plot(m))
                else
                    call viz_put(cli//'30m'//plot(m))
                endif
            endif
        enddo
        call viz_put(cli//'30m|')
    enddo
    call viz_pos(1,rows)
    call viz_put(cli//'30m')
    DO i=1,cols+1
       call viz_put('-')
    enddo

end subroutine viz_plot