program main
    implicit none
    interface

        subroutine read_file(filename, n, Ap, Ai, Ax)
            character(10),          intent(in)  :: filename
            integer,                intent(out) :: n
            integer, allocatable,   intent(out) :: Ap(:), Ai(:)
            real(8), allocatable,   intent(out) :: Ax(:)
        end subroutine

        subroutine gen_right(n, right)
            integer, intent(in)             :: n
            real(8), allocatable, intent(out)  :: right(:)
        end subroutine

        real(8) function distdot(n,x,ix,y,iy)
             integer n, ix, iy
             real(8) x(1+(n-1)*ix), y(1+(n-1)*iy)
        end function

    end interface

!===============================================================================================

    character(10)           :: filename
    integer                 :: n, i
    integer, allocatable    :: Ap(:), Ai(:)
    real(8), allocatable    :: Ax(:), right(:), result(:)

    integer iwk
    integer lfil

    real(8), allocatable :: alu(:), w(:)
    integer, allocatable :: jlu(:), ju(:), levs(:), jw(:), ierr


!================================================================================================

    ! INITIALIZATION
    read(*, *) filename
    call read_file(filename, n, Ap, Ai, Ax)
    call gen_right(n, right)
    allocate(result(n))

    iwk = 10 * (Ap(n + 1) - 1)
    lfil = 1

    allocate(alu(iwk), jlu(iwk), ju(n), levs(iwk), w(n), jw(3 * n))

!================================================================================================

    call iluk(n, Ax, Ai, Ap, lfil, alu, jlu, ju, levs, iwk, w, jw, ierr)

    deallocate(Ap, Ai, Ax, right, result)

end

subroutine read_file(filename, n, Ap, Ai, Ax)
    implicit none
    character(10),          intent(in)  :: filename
    integer,                intent(out) :: n
    integer, allocatable,   intent(out) :: Ap(:), Ai(:)
    real(8), allocatable,   intent(out) :: Ax(:)
    integer i

    open(1, file=filename)

    read(1, *) n
    print*, n
    print*,

    allocate(Ap(n + 1))
    read(1,*) (Ap(i), i = 1, n + 1)

    do i = 1, n + 1
        print*, Ap(i)
    end do
    print*,

    allocate(Ai(Ap(n + 1) - 1))
    read(1,*) (Ai(i), i = 1, Ap(n + 1) - 1)

    do i = 1, Ap(n + 1) - 1
        print*, Ai(i)
    end do
    print*,

    allocate(Ax(Ap(n + 1) - 1))
    read(1,*) (Ax(i), i = 1, Ap(n + 1) - 1)

    do i = 1, Ap(n + 1) - 1
        print*, Ax(i)
    end do
    print*,

end subroutine

subroutine gen_right(n, right)
    implicit none
    integer, intent(in)                 :: n
    real(8), allocatable, intent(out)   :: right(:)
    integer i

    allocate(right(n))
    do i = 1, n
        right(i) = sin(real(i, 8))
    end do
end subroutine

real(8) function distdot(n,x,ix,y,iy)
    integer n, ix, iy
    real(8) x(1+(n-1)*ix), y(1+(n-1)*iy)
    distdot = sdot(n, x, ix, y, iy)
end function