Пример #1
0
def mpi_communication_entrypoint():
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)

    from mpi4py import MPI
    comm = MPI.COMM_WORLD
    i_local_rank = comm.Get_rank()
    num_parts = comm.Get_size()

    from meshmode.distributed import MPIMeshDistributor, get_partition_by_pymetis
    mesh_dist = MPIMeshDistributor(comm)

    dim = 2
    dt = 0.04
    order = 4

    if mesh_dist.is_mananger_rank():
        from meshmode.mesh.generation import generate_regular_rect_mesh
        mesh = generate_regular_rect_mesh(a=(-0.5, ) * dim,
                                          b=(0.5, ) * dim,
                                          n=(16, ) * dim)

        part_per_element = get_partition_by_pymetis(mesh, num_parts)

        local_mesh = mesh_dist.send_mesh_parts(mesh, part_per_element,
                                               num_parts)
    else:
        local_mesh = mesh_dist.receive_mesh_part()

    vol_discr = DGDiscretizationWithBoundaries(cl_ctx,
                                               local_mesh,
                                               order=order,
                                               mpi_communicator=comm)

    source_center = np.array([0.1, 0.22, 0.33])[:local_mesh.dim]
    source_width = 0.05
    source_omega = 3

    sym_x = sym.nodes(local_mesh.dim)
    sym_source_center_dist = sym_x - source_center
    sym_t = sym.ScalarVariable("t")

    from grudge.models.wave import StrongWaveOperator
    from meshmode.mesh import BTAG_ALL, BTAG_NONE
    op = StrongWaveOperator(
        -0.1,
        vol_discr.dim,
        source_f=(
            sym.sin(source_omega * sym_t) *
            sym.exp(-np.dot(sym_source_center_dist, sym_source_center_dist) /
                    source_width**2)),
        dirichlet_tag=BTAG_NONE,
        neumann_tag=BTAG_NONE,
        radiation_tag=BTAG_ALL,
        flux_type="upwind")

    from pytools.obj_array import join_fields
    fields = join_fields(
        vol_discr.zeros(queue),
        [vol_discr.zeros(queue) for i in range(vol_discr.dim)])

    # FIXME
    # dt = op.estimate_rk4_timestep(vol_discr, fields=fields)

    # FIXME: Should meshmode consider BTAG_PARTITION to be a boundary?
    #           Fails because: "found faces without boundary conditions"
    # op.check_bc_coverage(local_mesh)

    from pytools.log import LogManager, \
            add_general_quantities, \
            add_run_info, \
            IntervalTimer, EventCounter
    log_filename = None
    # NOTE: LogManager hangs when using a file on a shared directory.
    # log_filename = 'grudge_log.dat'
    logmgr = LogManager(log_filename, "w", comm)
    add_run_info(logmgr)
    add_general_quantities(logmgr)
    log_quantities =\
        {"rank_data_swap_timer": IntervalTimer("rank_data_swap_timer",
        "Time spent evaluating RankDataSwapAssign"),
        "rank_data_swap_counter": EventCounter("rank_data_swap_counter",
        "Number of RankDataSwapAssign instructions evaluated"),
        "exec_timer": IntervalTimer("exec_timer",
        "Total time spent executing instructions"),
        "insn_eval_timer": IntervalTimer("insn_eval_timer",
        "Time spend evaluating instructions"),
        "future_eval_timer": IntervalTimer("future_eval_timer",
        "Time spent evaluating futures"),
        "busy_wait_timer": IntervalTimer("busy_wait_timer",
        "Time wasted doing busy wait")}
    for quantity in log_quantities.values():
        logmgr.add_quantity(quantity)

    # print(sym.pretty(op.sym_operator()))
    bound_op = bind(vol_discr, op.sym_operator())

    # print(bound_op)
    # 1/0

    def rhs(t, w):
        val, rhs.profile_data = bound_op(queue,
                                         profile_data=rhs.profile_data,
                                         log_quantities=log_quantities,
                                         t=t,
                                         w=w)
        return val

    rhs.profile_data = {}

    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    final_t = 4
    nsteps = int(final_t / dt)
    print("rank=%d dt=%g nsteps=%d" % (i_local_rank, dt, nsteps))

    # from grudge.shortcuts import make_visualizer
    # vis = make_visualizer(vol_discr, vis_order=order)

    step = 0

    norm = bind(vol_discr, sym.norm(2, sym.var("u")))

    from time import time
    t_last_step = time()

    logmgr.tick_before()
    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1
            print(step, event.t, norm(queue, u=event.state_component[0]),
                  time() - t_last_step)

            # if step % 10 == 0:
            #     vis.write_vtk_file("rank%d-fld-%04d.vtu" % (i_local_rank, step),
            #                        [("u", event.state_component[0]),
            #                         ("v", event.state_component[1:])])
            t_last_step = time()
            logmgr.tick_after()
            logmgr.tick_before()
    logmgr.tick_after()

    def print_profile_data(data):
        print("""execute() for rank %d:
            \tInstruction Evaluation: %f%%
            \tFuture Evaluation: %f%%
            \tBusy Wait: %f%%
            \tTotal: %f seconds""" %
              (i_local_rank, data['insn_eval_time'] / data['total_time'] * 100,
               data['future_eval_time'] / data['total_time'] * 100,
               data['busy_wait_time'] / data['total_time'] * 100,
               data['total_time']))

    print_profile_data(rhs.profile_data)
    logmgr.close()
    logger.debug("Rank %d exiting", i_local_rank)
Пример #2
0
def simple_wave_entrypoint(dim=2, num_elems=256, order=4, num_steps=30,
                           log_filename="grudge.dat"):
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)

    from mpi4py import MPI
    comm = MPI.COMM_WORLD
    num_parts = comm.Get_size()
    n = int(num_elems ** (1./dim))

    from meshmode.distributed import MPIMeshDistributor
    mesh_dist = MPIMeshDistributor(comm)

    if mesh_dist.is_mananger_rank():
        from meshmode.mesh.generation import generate_regular_rect_mesh
        mesh = generate_regular_rect_mesh(a=(-0.5,)*dim,
                                          b=(0.5,)*dim,
                                          n=(n,)*dim)

        from pymetis import part_graph
        _, p = part_graph(num_parts,
                          xadj=mesh.nodal_adjacency.neighbors_starts.tolist(),
                          adjncy=mesh.nodal_adjacency.neighbors.tolist())
        part_per_element = np.array(p)

        local_mesh = mesh_dist.send_mesh_parts(mesh, part_per_element, num_parts)
    else:
        local_mesh = mesh_dist.receive_mesh_part()

    vol_discr = DGDiscretizationWithBoundaries(cl_ctx, local_mesh, order=order,
                                               mpi_communicator=comm)

    source_center = np.array([0.1, 0.22, 0.33])[:local_mesh.dim]
    source_width = 0.05
    source_omega = 3

    sym_x = sym.nodes(local_mesh.dim)
    sym_source_center_dist = sym_x - source_center
    sym_t = sym.ScalarVariable("t")

    from grudge.models.wave import StrongWaveOperator
    from meshmode.mesh import BTAG_ALL, BTAG_NONE
    op = StrongWaveOperator(-0.1, vol_discr.dim,
            source_f=(
                sym.sin(source_omega*sym_t)
                * sym.exp(
                    -np.dot(sym_source_center_dist, sym_source_center_dist)
                    / source_width**2)),
            dirichlet_tag=BTAG_NONE,
            neumann_tag=BTAG_NONE,
            radiation_tag=BTAG_ALL,
            flux_type="upwind")

    from pytools.obj_array import join_fields
    fields = join_fields(vol_discr.zeros(queue),
            [vol_discr.zeros(queue) for i in range(vol_discr.dim)])

    from logpyle import LogManager, \
            add_general_quantities, \
            add_run_info, \
            IntervalTimer, EventCounter
    # NOTE: LogManager hangs when using a file on a shared directory.
    logmgr = LogManager(log_filename, "w", comm)
    add_run_info(logmgr)
    add_general_quantities(logmgr)
    log_quantities =\
        {"rank_data_swap_timer": IntervalTimer("rank_data_swap_timer",
                        "Time spent evaluating RankDataSwapAssign"),
        "rank_data_swap_counter": EventCounter("rank_data_swap_counter",
                        "Number of RankDataSwapAssign instructions evaluated"),
        "exec_timer": IntervalTimer("exec_timer",
                        "Total time spent executing instructions"),
        "insn_eval_timer": IntervalTimer("insn_eval_timer",
                        "Time spend evaluating instructions"),
        "future_eval_timer": IntervalTimer("future_eval_timer",
                        "Time spent evaluating futures"),
        "busy_wait_timer": IntervalTimer("busy_wait_timer",
                        "Time wasted doing busy wait")}
    for quantity in log_quantities.values():
        logmgr.add_quantity(quantity)

    bound_op = bind(vol_discr, op.sym_operator())

    def rhs(t, w):
        val, rhs.profile_data = bound_op(queue, profile_data=rhs.profile_data,
                                                log_quantities=log_quantities,
                                                t=t, w=w)
        return val
    rhs.profile_data = {}

    dt = 0.04
    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    logmgr.tick_before()
    for event in dt_stepper.run(t_end=dt * num_steps):
        if isinstance(event, dt_stepper.StateComputed):
            logmgr.tick_after()
            logmgr.tick_before()
    logmgr.tick_after()

    def print_profile_data(data):
        print("""execute() for rank %d:
            \tInstruction Evaluation: %f%%
            \tFuture Evaluation: %f%%
            \tBusy Wait: %f%%
            \tTotal: %f seconds""" %
            (comm.Get_rank(),
             data['insn_eval_time'] / data['total_time'] * 100,
             data['future_eval_time'] / data['total_time'] * 100,
             data['busy_wait_time'] / data['total_time'] * 100,
             data['total_time']))

    print_profile_data(rhs.profile_data)
    logmgr.close()
Пример #3
0
def main(ctx_factory, dim=3, order=4, visualize=False):
    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(
        queue,
        allocator=cl_tools.MemoryPool(cl_tools.ImmediateAllocator(queue)),
        force_device_scalars=True,
    )

    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(a=(0.0, ) * dim,
                                      b=(1.0, ) * dim,
                                      nelements_per_axis=(4, ) * dim)

    dcoll = DiscretizationCollection(actx, mesh, order=order)

    if 0:
        epsilon0 = 8.8541878176e-12  # C**2 / (N m**2)
        mu0 = 4 * np.pi * 1e-7  # N/A**2.
        epsilon = 1 * epsilon0
        mu = 1 * mu0
    else:
        epsilon = 1
        mu = 1

    from grudge.models.em import MaxwellOperator

    maxwell_operator = MaxwellOperator(dcoll,
                                       epsilon,
                                       mu,
                                       flux_type=0.5,
                                       dimensions=dim)

    def cavity_mode(x, t=0):
        if dim == 3:
            return get_rectangular_cavity_mode(actx, x, t, 1, (1, 2, 2))
        else:
            return get_rectangular_cavity_mode(actx, x, t, 1, (2, 3))

    fields = cavity_mode(thaw(dcoll.nodes(), actx), t=0)

    maxwell_operator.check_bc_coverage(mesh)

    def rhs(t, w):
        return maxwell_operator.operator(t, w)

    dt = maxwell_operator.estimate_rk4_timestep(actx, dcoll, fields=fields)

    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    target_steps = 60
    final_t = dt * target_steps
    nsteps = int(final_t / dt) + 1

    logger.info("dt = %g nsteps = %d", dt, nsteps)

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(dcoll)

    step = 0

    def norm(u):
        return op.norm(dcoll, u, 2)

    e, h = maxwell_operator.split_eh(fields)

    if visualize:
        vis.write_vtk_file(f"fld-cavities-{step:04d}.vtu", [
            ("e", e),
            ("h", h),
        ])

    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1
            e, h = maxwell_operator.split_eh(event.state_component)

            norm_e0 = actx.to_numpy(norm(u=e[0]))
            norm_e1 = actx.to_numpy(norm(u=e[1]))
            norm_h0 = actx.to_numpy(norm(u=h[0]))
            norm_h1 = actx.to_numpy(norm(u=h[1]))

            logger.info(
                "[%04d] t = %.5f |e0| = %.5e, |e1| = %.5e, |h0| = %.5e, |h1| = %.5e",
                step, event.t, norm_e0, norm_e1, norm_h0, norm_h1)

            if step % 10 == 0:
                if visualize:
                    vis.write_vtk_file(f"fld-cavities-{step:04d}.vtu", [
                        ("e", e),
                        ("h", h),
                    ])

            # NOTE: These are here to ensure the solution is bounded for the
            # time interval specified
            assert norm_e0 < 0.5
            assert norm_e1 < 0.5
            assert norm_h0 < 0.5
            assert norm_h1 < 0.5
Пример #4
0
def main(ctx_factory, dim=2, order=4, visualize=False):
    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(
        queue,
        allocator=cl_tools.MemoryPool(cl_tools.ImmediateAllocator(queue)),
        force_device_scalars=True,
    )

    # {{{ parameters

    # domain [-d/2, d/2]^dim
    d = 1.0
    # number of points in each dimension
    npoints = 20

    # final time
    final_time = 1.0

    # velocity field
    c = np.array([0.5] * dim)
    norm_c = la.norm(c)

    # flux
    flux_type = "central"

    # }}}

    # {{{ discretization

    from meshmode.mesh.generation import generate_box_mesh
    mesh = generate_box_mesh(
        [np.linspace(-d / 2, d / 2, npoints) for _ in range(dim)], order=order)

    from grudge import DiscretizationCollection

    dcoll = DiscretizationCollection(actx, mesh, order=order)

    # }}}

    # {{{ weak advection operator

    def f(x):
        return actx.np.sin(3 * x)

    def u_analytic(x, t=0):
        return f(-np.dot(c, x) / norm_c + t * norm_c)

    from grudge.models.advection import WeakAdvectionOperator

    adv_operator = WeakAdvectionOperator(
        dcoll,
        c,
        inflow_u=lambda t: u_analytic(thaw(dcoll.nodes(dd=BTAG_ALL), actx),
                                      t=t),
        flux_type=flux_type)

    nodes = thaw(dcoll.nodes(), actx)
    u = u_analytic(nodes, t=0)

    def rhs(t, u):
        return adv_operator.operator(t, u)

    dt = actx.to_numpy(
        adv_operator.estimate_rk4_timestep(actx, dcoll, fields=u))

    logger.info("Timestep size: %g", dt)

    # }}}

    # {{{ time stepping

    from grudge.shortcuts import set_up_rk4
    dt_stepper = set_up_rk4("u", dt, u, rhs)
    plot = Plotter(actx, dcoll, order, visualize=visualize, ylim=[-1.1, 1.1])

    step = 0
    norm_u = 0.0
    for event in dt_stepper.run(t_end=final_time):
        if not isinstance(event, dt_stepper.StateComputed):
            continue

        if step % 10 == 0:
            norm_u = actx.to_numpy(op.norm(dcoll, event.state_component, 2))
            plot(event, "fld-weak-%04d" % step)

        step += 1
        logger.info("[%04d] t = %.5f |u| = %.5e", step, event.t, norm_u)

        # NOTE: These are here to ensure the solution is bounded for the
        # time interval specified
        assert norm_u < 1
Пример #5
0
def mpi_communication_entrypoint():
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue, force_device_scalars=True)

    from mpi4py import MPI
    comm = MPI.COMM_WORLD
    i_local_rank = comm.Get_rank()
    num_parts = comm.Get_size()

    from meshmode.distributed import MPIMeshDistributor, get_partition_by_pymetis
    mesh_dist = MPIMeshDistributor(comm)

    dim = 2
    order = 4

    if mesh_dist.is_mananger_rank():
        from meshmode.mesh.generation import generate_regular_rect_mesh
        mesh = generate_regular_rect_mesh(a=(-0.5,)*dim,
                                          b=(0.5,)*dim,
                                          nelements_per_axis=(16,)*dim)

        part_per_element = get_partition_by_pymetis(mesh, num_parts)

        local_mesh = mesh_dist.send_mesh_parts(mesh, part_per_element, num_parts)

        del mesh
    else:
        local_mesh = mesh_dist.receive_mesh_part()

    dcoll = DiscretizationCollection(actx, local_mesh, order=order,
                                     mpi_communicator=comm)

    def source_f(actx, dcoll, t=0):
        source_center = np.array([0.1, 0.22, 0.33])[:dcoll.dim]
        source_width = 0.05
        source_omega = 3
        nodes = thaw(dcoll.nodes(), actx)
        source_center_dist = flat_obj_array(
            [nodes[i] - source_center[i] for i in range(dcoll.dim)]
        )
        return (
            np.sin(source_omega*t)
            * actx.np.exp(
                -np.dot(source_center_dist, source_center_dist)
                / source_width**2
            )
        )

    from grudge.models.wave import WeakWaveOperator
    from meshmode.mesh import BTAG_ALL, BTAG_NONE

    wave_op = WeakWaveOperator(
        dcoll,
        0.1,
        source_f=source_f,
        dirichlet_tag=BTAG_NONE,
        neumann_tag=BTAG_NONE,
        radiation_tag=BTAG_ALL,
        flux_type="upwind"
    )

    fields = flat_obj_array(
        dcoll.zeros(actx),
        [dcoll.zeros(actx) for i in range(dcoll.dim)]
    )

    dt = actx.to_numpy(
        2/3 * wave_op.estimate_rk4_timestep(actx, dcoll, fields=fields))

    wave_op.check_bc_coverage(local_mesh)

    from logpyle import LogManager, \
            add_general_quantities, \
            add_run_info
    log_filename = None
    # NOTE: LogManager hangs when using a file on a shared directory.
    # log_filename = "grudge_log.dat"
    logmgr = LogManager(log_filename, "w", comm)
    add_run_info(logmgr)
    add_general_quantities(logmgr)

    def rhs(t, w):
        return wave_op.operator(t, w)

    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    final_t = 4
    nsteps = int(final_t/dt)
    logger.info("[%04d] dt %.5e nsteps %4d", i_local_rank, dt, nsteps)

    step = 0

    def norm(u):
        return op.norm(dcoll, u, 2)

    from time import time
    t_last_step = time()

    logmgr.tick_before()
    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1
            logger.info("[%04d] t = %.5e |u| = %.5e ellapsed %.5e",
                        step, event.t,
                        norm(u=event.state_component[0]),
                        time() - t_last_step)

            t_last_step = time()
            logmgr.tick_after()
            logmgr.tick_before()

    logmgr.tick_after()
    logmgr.close()
    logger.info("Rank %d exiting", i_local_rank)
Пример #6
0
def test_convergence_maxwell(ctx_factory, order):
    """Test whether 3D Maxwell's actually converges"""

    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue)

    from pytools.convergence import EOCRecorder
    eoc_rec = EOCRecorder()

    dims = 3
    ns = [4, 6, 8]
    for n in ns:
        from meshmode.mesh.generation import generate_regular_rect_mesh
        mesh = generate_regular_rect_mesh(a=(0.0, ) * dims,
                                          b=(1.0, ) * dims,
                                          n=(n, ) * dims)

        discr = DGDiscretizationWithBoundaries(actx, mesh, order=order)

        epsilon = 1
        mu = 1

        from grudge.models.em import get_rectangular_cavity_mode
        sym_mode = get_rectangular_cavity_mode(1, (1, 2, 2))

        analytic_sol = bind(discr, sym_mode)
        fields = analytic_sol(actx, t=0, epsilon=epsilon, mu=mu)

        from grudge.models.em import MaxwellOperator
        op = MaxwellOperator(epsilon, mu, flux_type=0.5, dimensions=dims)
        op.check_bc_coverage(mesh)
        bound_op = bind(discr, op.sym_operator())

        def rhs(t, w):
            return bound_op(t=t, w=w)

        dt = 0.002
        final_t = dt * 5
        nsteps = int(final_t / dt)

        from grudge.shortcuts import set_up_rk4
        dt_stepper = set_up_rk4("w", dt, fields, rhs)

        logger.info("dt %.5e nsteps %5d", dt, nsteps)

        norm = bind(discr, sym.norm(2, sym.var("u")))

        step = 0
        for event in dt_stepper.run(t_end=final_t):
            if isinstance(event, dt_stepper.StateComputed):
                assert event.component_id == "w"
                esc = event.state_component

                step += 1
                logger.debug("[%04d] t = %.5e", step, event.t)

        sol = analytic_sol(actx, mu=mu, epsilon=epsilon, t=step * dt)
        vals = [norm(u=(esc[i] - sol[i])) / norm(u=sol[i])
                for i in range(5)]  # noqa E501
        total_error = sum(vals)
        eoc_rec.add_data_point(1.0 / n, total_error)

    logger.info(
        "\n%s", eoc_rec.pretty_print(abscissa_label="h",
                                     error_label="L2 Error"))

    assert eoc_rec.order_estimate() > order
Пример #7
0
def main(dims, write_output=True, order=4):
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue)

    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(a=(0.0, ) * dims,
                                      b=(1.0, ) * dims,
                                      nelements_per_axis=(4, ) * dims)

    discr = DiscretizationCollection(actx, mesh, order=order)

    if 0:
        epsilon0 = 8.8541878176e-12  # C**2 / (N m**2)
        mu0 = 4 * np.pi * 1e-7  # N/A**2.
        epsilon = 1 * epsilon0
        mu = 1 * mu0
    else:
        epsilon = 1
        mu = 1

    from grudge.models.em import MaxwellOperator
    op = MaxwellOperator(epsilon, mu, flux_type=0.5, dimensions=dims)

    if dims == 3:
        sym_mode = get_rectangular_cavity_mode(1, (1, 2, 2))
        fields = bind(discr, sym_mode)(actx, t=0, epsilon=epsilon, mu=mu)
    else:
        sym_mode = get_rectangular_cavity_mode(1, (2, 3))
        fields = bind(discr, sym_mode)(actx, t=0)

    # FIXME
    #dt = op.estimate_rk4_timestep(discr, fields=fields)

    op.check_bc_coverage(mesh)

    # print(sym.pretty(op.sym_operator()))
    bound_op = bind(discr, op.sym_operator())

    def rhs(t, w):
        return bound_op(t=t, w=w)

    if mesh.dim == 2:
        dt = 0.004
    elif mesh.dim == 3:
        dt = 0.002

    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    final_t = dt * STEPS
    nsteps = int(final_t / dt)

    print("dt=%g nsteps=%d" % (dt, nsteps))

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(discr)

    step = 0

    norm = bind(discr, sym.norm(2, sym.var("u")))

    from time import time
    t_last_step = time()

    e, h = op.split_eh(fields)

    if 1:
        vis.write_vtk_file("fld-cavities-%04d.vtu" % step, [
            ("e", e),
            ("h", h),
        ])

    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1

            print(step, event.t, norm(u=e[0]), norm(u=e[1]), norm(u=h[0]),
                  norm(u=h[1]),
                  time() - t_last_step)
            if step % 10 == 0:
                e, h = op.split_eh(event.state_component)
                vis.write_vtk_file("fld-cavities-%04d.vtu" % step, [
                    ("e", e),
                    ("h", h),
                ])
            t_last_step = time()
def main(write_output=True, order=4):
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue)

    dims = 2
    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(
            a=(-0.5,)*dims,
            b=(0.5,)*dims,
            nelements_per_axis=(20,)*dims)

    discr = DiscretizationCollection(actx, mesh, order=order)

    source_center = np.array([0.1, 0.22, 0.33])[:mesh.dim]
    source_width = 0.05
    source_omega = 3

    sym_x = sym.nodes(mesh.dim)
    sym_source_center_dist = sym_x - source_center
    sym_t = sym.ScalarVariable("t")
    c = sym.If(sym.Comparison(
                np.dot(sym_x, sym_x), "<", 0.15),
                np.float32(0.1), np.float32(0.2))

    from grudge.models.wave import VariableCoefficientWeakWaveOperator
    from meshmode.mesh import BTAG_ALL, BTAG_NONE
    op = VariableCoefficientWeakWaveOperator(c,
            discr.dim,
            source_f=(
                sym.sin(source_omega*sym_t)
                * sym.exp(
                    -np.dot(sym_source_center_dist, sym_source_center_dist)
                    / source_width**2)),
            dirichlet_tag=BTAG_NONE,
            neumann_tag=BTAG_NONE,
            radiation_tag=BTAG_ALL,
            flux_type="upwind")

    from pytools.obj_array import flat_obj_array
    fields = flat_obj_array(discr.zeros(actx),
            [discr.zeros(actx) for i in range(discr.dim)])

    op.check_bc_coverage(mesh)

    c_eval = bind(discr, c)(actx)

    bound_op = bind(discr, op.sym_operator())

    def rhs(t, w):
        return bound_op(t=t, w=w)

    if mesh.dim == 2:
        dt = 0.04 * 0.3
    elif mesh.dim == 3:
        dt = 0.02 * 0.1

    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    final_t = 1
    nsteps = int(final_t/dt)
    print("dt=%g nsteps=%d" % (dt, nsteps))

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(discr)

    step = 0

    norm = bind(discr, sym.norm(2, sym.var("u")))

    from time import time
    t_last_step = time()

    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1

            print(step, event.t, norm(u=event.state_component[0]),
                    time()-t_last_step)
            if step % 10 == 0:
                vis.write_vtk_file("fld-var-propogation-speed-%04d.vtu" % step,
                        [
                            ("u", event.state_component[0]),
                            ("v", event.state_component[1:]),
                            ("c", c_eval),
                            ])
            t_last_step = time()
Пример #9
0
def main(ctx_factory, dim=2, order=4, visualize=False):
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(
        queue,
        allocator=cl_tools.MemoryPool(cl_tools.ImmediateAllocator(queue)),
        force_device_scalars=True,
    )

    comm = MPI.COMM_WORLD
    num_parts = comm.Get_size()

    from meshmode.distributed import MPIMeshDistributor, get_partition_by_pymetis
    mesh_dist = MPIMeshDistributor(comm)

    if mesh_dist.is_mananger_rank():
        from meshmode.mesh.generation import generate_regular_rect_mesh
        mesh = generate_regular_rect_mesh(a=(-0.5, ) * dim,
                                          b=(0.5, ) * dim,
                                          nelements_per_axis=(16, ) * dim)

        logger.info("%d elements", mesh.nelements)

        part_per_element = get_partition_by_pymetis(mesh, num_parts)

        local_mesh = mesh_dist.send_mesh_parts(mesh, part_per_element,
                                               num_parts)

        del mesh

    else:
        local_mesh = mesh_dist.receive_mesh_part()

    dcoll = DiscretizationCollection(actx,
                                     local_mesh,
                                     order=order,
                                     mpi_communicator=comm)

    def source_f(actx, dcoll, t=0):
        source_center = np.array([0.1, 0.22, 0.33])[:dcoll.dim]
        source_width = 0.05
        source_omega = 3
        nodes = thaw(dcoll.nodes(), actx)
        source_center_dist = flat_obj_array(
            [nodes[i] - source_center[i] for i in range(dcoll.dim)])
        return (np.sin(source_omega * t) * actx.np.exp(
            -np.dot(source_center_dist, source_center_dist) / source_width**2))

    from grudge.models.wave import WeakWaveOperator
    from meshmode.mesh import BTAG_ALL, BTAG_NONE

    wave_op = WeakWaveOperator(dcoll,
                               0.1,
                               source_f=source_f,
                               dirichlet_tag=BTAG_NONE,
                               neumann_tag=BTAG_NONE,
                               radiation_tag=BTAG_ALL,
                               flux_type="upwind")

    fields = flat_obj_array(dcoll.zeros(actx),
                            [dcoll.zeros(actx) for i in range(dcoll.dim)])

    dt = 2 / 3 * wave_op.estimate_rk4_timestep(actx, dcoll, fields=fields)

    wave_op.check_bc_coverage(local_mesh)

    def rhs(t, w):
        return wave_op.operator(t, w)

    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    final_t = 10
    nsteps = int(final_t / dt) + 1

    if comm.rank == 0:
        logger.info("dt=%g nsteps=%d", dt, nsteps)

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(dcoll)

    step = 0

    def norm(u):
        return op.norm(dcoll, u, 2)

    from time import time
    t_last_step = time()

    if visualize:
        u = fields[0]
        v = fields[1:]
        vis.write_parallel_vtk_file(
            comm, f"fld-wave-min-mpi-{{rank:03d}}-{step:04d}.vtu", [
                ("u", u),
                ("v", v),
            ])

    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1
            l2norm = norm(u=event.state_component[0])

            if step % 10 == 0:
                if comm.rank == 0:
                    logger.info(f"step: {step} "
                                f"t: {time()-t_last_step} "
                                f"L2: {l2norm}")
                if visualize:
                    vis.write_parallel_vtk_file(
                        comm, f"fld-wave-min-mpi-{{rank:03d}}-{step:04d}.vtu",
                        [
                            ("u", event.state_component[0]),
                            ("v", event.state_component[1:]),
                        ])
            t_last_step = time()

            # NOTE: These are here to ensure the solution is bounded for the
            # time interval specified
            assert l2norm < 1
Пример #10
0
def test_convergence_maxwell(actx_factory, order):
    """Test whether 3D Maxwell's actually converges"""

    actx = actx_factory()

    from pytools.convergence import EOCRecorder
    eoc_rec = EOCRecorder()

    dims = 3
    ns = [4, 6, 8]
    for n in ns:
        mesh = mgen.generate_regular_rect_mesh(a=(0.0, ) * dims,
                                               b=(1.0, ) * dims,
                                               nelements_per_axis=(n, ) * dims)

        dcoll = DiscretizationCollection(actx, mesh, order=order)

        epsilon = 1
        mu = 1

        from grudge.models.em import get_rectangular_cavity_mode

        def analytic_sol(x, t=0):
            return get_rectangular_cavity_mode(actx, x, t, 1, (1, 2, 2))

        nodes = thaw(dcoll.nodes(), actx)
        fields = analytic_sol(nodes, t=0)

        from grudge.models.em import MaxwellOperator

        maxwell_operator = MaxwellOperator(dcoll,
                                           epsilon,
                                           mu,
                                           flux_type=0.5,
                                           dimensions=dims)
        maxwell_operator.check_bc_coverage(mesh)

        def rhs(t, w):
            return maxwell_operator.operator(t, w)

        dt = maxwell_operator.estimate_rk4_timestep(actx, dcoll)
        final_t = dt * 5
        nsteps = int(final_t / dt)

        from grudge.shortcuts import set_up_rk4
        dt_stepper = set_up_rk4("w", dt, fields, rhs)

        logger.info("dt %.5e nsteps %5d", dt, nsteps)

        step = 0
        for event in dt_stepper.run(t_end=final_t):
            if isinstance(event, dt_stepper.StateComputed):
                assert event.component_id == "w"
                esc = event.state_component

                step += 1
                logger.debug("[%04d] t = %.5e", step, event.t)

        sol = analytic_sol(nodes, t=step * dt)
        total_error = op.norm(dcoll, esc - sol, 2)
        eoc_rec.add_data_point(1.0 / n, actx.to_numpy(total_error))

    logger.info(
        "\n%s", eoc_rec.pretty_print(abscissa_label="h",
                                     error_label="L2 Error"))

    assert eoc_rec.order_estimate() > order
Пример #11
0
def main(write_output=True, order=4):
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)

    dims = 2
    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(a=(-0.5, ) * dims,
                                      b=(0.5, ) * dims,
                                      n=(16, ) * dims)

    if mesh.dim == 2:
        dt = 0.04
    elif mesh.dim == 3:
        dt = 0.02

    print("%d elements" % mesh.nelements)

    discr = DGDiscretizationWithBoundaries(cl_ctx, mesh, order=order)

    source_center = np.array([0.1, 0.22, 0.33])[:mesh.dim]
    source_width = 0.05
    source_omega = 3

    sym_x = sym.nodes(mesh.dim)
    sym_source_center_dist = sym_x - source_center
    sym_t = sym.ScalarVariable("t")

    from grudge.models.wave import StrongWaveOperator
    from meshmode.mesh import BTAG_ALL, BTAG_NONE
    op = StrongWaveOperator(
        -0.1,
        discr.dim,
        source_f=(
            sym.sin(source_omega * sym_t) *
            sym.exp(-np.dot(sym_source_center_dist, sym_source_center_dist) /
                    source_width**2)),
        dirichlet_tag=BTAG_NONE,
        neumann_tag=BTAG_NONE,
        radiation_tag=BTAG_ALL,
        flux_type="upwind")

    queue = cl.CommandQueue(discr.cl_context)
    from pytools.obj_array import join_fields
    fields = join_fields(discr.zeros(queue),
                         [discr.zeros(queue) for i in range(discr.dim)])

    # FIXME
    #dt = op.estimate_rk4_timestep(discr, fields=fields)

    op.check_bc_coverage(mesh)

    # print(sym.pretty(op.sym_operator()))
    bound_op = bind(discr, op.sym_operator())

    def rhs(t, w):
        return bound_op(queue, t=t, w=w)

    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    final_t = 10
    nsteps = int(final_t / dt)
    print("dt=%g nsteps=%d" % (dt, nsteps))

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(discr, vis_order=order)

    step = 0

    norm = bind(discr, sym.norm(2, sym.var("u")))

    from time import time
    t_last_step = time()

    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1

            print(step, event.t, norm(queue, u=event.state_component[0]),
                  time() - t_last_step)
            if step % 10 == 0:
                vis.write_vtk_file("fld-wave-min-%04d.vtu" % step, [
                    ("u", event.state_component[0]),
                    ("v", event.state_component[1:]),
                ])
            t_last_step = time()
Пример #12
0
def test_convergence_advec(actx_factory,
                           mesh_name,
                           mesh_pars,
                           op_type,
                           flux_type,
                           order,
                           visualize=False):
    """Test whether 2D advection actually converges"""

    actx = actx_factory()

    from pytools.convergence import EOCRecorder
    eoc_rec = EOCRecorder()

    for mesh_par in mesh_pars:
        if mesh_name == "segment":
            mesh = mgen.generate_box_mesh([np.linspace(-1.0, 1.0, mesh_par)],
                                          order=order)

            dim = 1
            dt_factor = 1.0
        elif mesh_name == "disk":
            pytest.importorskip("meshpy")

            from meshpy.geometry import make_circle, GeometryBuilder
            from meshpy.triangle import MeshInfo, build

            geob = GeometryBuilder()
            geob.add_geometry(*make_circle(1))
            mesh_info = MeshInfo()
            geob.set(mesh_info)

            mesh_info = build(mesh_info, max_volume=mesh_par)

            from meshmode.mesh.io import from_meshpy
            mesh = from_meshpy(mesh_info, order=1)
            dim = 2
            dt_factor = 4
        elif mesh_name.startswith("rect"):
            dim = int(mesh_name[-1:])
            mesh = mgen.generate_regular_rect_mesh(
                a=(-0.5, ) * dim,
                b=(0.5, ) * dim,
                nelements_per_axis=(mesh_par, ) * dim,
                order=4)

            if dim == 2:
                dt_factor = 4
            elif dim == 3:
                dt_factor = 2
            else:
                raise ValueError("dt_factor not known for %dd" % dim)
        elif mesh_name.startswith("warped"):
            dim = int(mesh_name[-1:])
            mesh = mgen.generate_warped_rect_mesh(dim,
                                                  order=order,
                                                  nelements_side=mesh_par)

            if dim == 2:
                dt_factor = 4
            elif dim == 3:
                dt_factor = 2
            else:
                raise ValueError("dt_factor not known for %dd" % dim)
        else:
            raise ValueError("invalid mesh name: " + mesh_name)

        v = np.array([0.27, 0.31, 0.1])[:dim]
        norm_v = la.norm(v)

        def f(x):
            return actx.np.sin(10 * x)

        def u_analytic(x, t=0):
            return f(-v.dot(x) / norm_v + t * norm_v)

        from grudge.models.advection import (StrongAdvectionOperator,
                                             WeakAdvectionOperator)
        from meshmode.mesh import BTAG_ALL

        dcoll = DiscretizationCollection(actx, mesh, order=order)
        op_class = {
            "strong": StrongAdvectionOperator,
            "weak": WeakAdvectionOperator
        }[op_type]
        adv_operator = op_class(dcoll,
                                v,
                                inflow_u=lambda t: u_analytic(
                                    thaw(dcoll.nodes(dd=BTAG_ALL), actx), t=t),
                                flux_type=flux_type)

        nodes = thaw(dcoll.nodes(), actx)
        u = u_analytic(nodes, t=0)

        def rhs(t, u):
            return adv_operator.operator(t, u)

        if dim == 3:
            final_time = 0.1
        else:
            final_time = 0.2

        from grudge.dt_utils import h_max_from_volume

        h_max = h_max_from_volume(dcoll, dim=dcoll.ambient_dim)
        dt = dt_factor * h_max / order**2
        nsteps = (final_time // dt) + 1
        dt = final_time / nsteps + 1e-15

        from grudge.shortcuts import set_up_rk4
        dt_stepper = set_up_rk4("u", dt, u, rhs)

        last_u = None

        from grudge.shortcuts import make_visualizer
        vis = make_visualizer(dcoll)

        step = 0

        for event in dt_stepper.run(t_end=final_time):
            if isinstance(event, dt_stepper.StateComputed):
                step += 1
                logger.debug("[%04d] t = %.5f", step, event.t)

                last_t = event.t
                last_u = event.state_component

                if visualize:
                    vis.write_vtk_file("fld-%s-%04d.vtu" % (mesh_par, step),
                                       [("u", event.state_component)])

        error_l2 = op.norm(dcoll, last_u - u_analytic(nodes, t=last_t), 2)
        logger.info("h_max %.5e error %.5e", h_max, error_l2)
        eoc_rec.add_data_point(h_max, actx.to_numpy(error_l2))

    logger.info(
        "\n%s", eoc_rec.pretty_print(abscissa_label="h",
                                     error_label="L2 Error"))

    if mesh_name.startswith("warped"):
        # NOTE: curvilinear meshes are hard
        assert eoc_rec.order_estimate() > order - 0.5
    else:
        assert eoc_rec.order_estimate() > order
Пример #13
0
def main(write_output=True, order=4):
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)

    dim = 2

    resolution = 15
    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(a=(-0.5, -0.5),
                                      b=(0.5, 0.5),
                                      n=(resolution, resolution),
                                      order=order)

    dt_factor = 5
    h = 1 / resolution

    sym_x = sym.nodes(2)

    advec_v = join_fields(-1 * sym_x[1], sym_x[0]) / 2

    flux_type = "upwind"

    source_center = np.array([0.1, 0.1])
    source_width = 0.05

    sym_x = sym.nodes(2)
    sym_source_center_dist = sym_x - source_center

    def f_gaussian(x):
        return sym.exp(
            -np.dot(sym_source_center_dist, sym_source_center_dist) /
            source_width**2)

    def f_step(x):
        return sym.If(
            sym.Comparison(
                np.dot(sym_source_center_dist, sym_source_center_dist), "<",
                (4 * source_width)**2), 1, 0)

    def u_analytic(x):
        return 0

    from grudge.models.advection import VariableCoefficientAdvectionOperator
    from meshmode.discretization.poly_element import QuadratureSimplexGroupFactory  # noqa

    discr = DGDiscretizationWithBoundaries(
        cl_ctx,
        mesh,
        order=order,
        quad_tag_to_group_factory={
            #"product": None,
            "product": QuadratureSimplexGroupFactory(order=4 * order)
        })

    op = VariableCoefficientAdvectionOperator(2,
                                              advec_v,
                                              u_analytic(
                                                  sym.nodes(dim,
                                                            sym.BTAG_ALL)),
                                              quad_tag="product",
                                              flux_type=flux_type)

    bound_op = bind(
        discr,
        op.sym_operator(),
        #debug_flags=["dump_sym_operator_stages"]
    )

    u = bind(discr, f_gaussian(sym.nodes(dim)))(queue, t=0)

    def rhs(t, u):
        return bound_op(queue, t=t, u=u)

    dt = dt_factor * h / order**2
    nsteps = (FINAL_TIME // dt) + 1
    dt = FINAL_TIME / nsteps + 1e-15

    from grudge.shortcuts import set_up_rk4
    dt_stepper = set_up_rk4("u", dt, u, rhs)

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(discr, vis_order=2 * order)

    step = 0

    for event in dt_stepper.run(t_end=FINAL_TIME):
        if isinstance(event, dt_stepper.StateComputed):

            step += 1
            if step % 30 == 0:
                print(step)

                vis.write_vtk_file("fld-var-velocity-%04d.vtu" % step,
                                   [("u", event.state_component)])
Пример #14
0
def main(ctx_factory, dim=2, order=4, use_quad=False, visualize=False):
    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(
        queue,
        allocator=cl_tools.MemoryPool(cl_tools.ImmediateAllocator(queue)),
        force_device_scalars=True,
    )

    # {{{ parameters

    # sphere radius
    radius = 1.0
    # sphere resolution
    resolution = 64 if dim == 2 else 1

    # final time
    final_time = np.pi

    # flux
    flux_type = "lf"

    # }}}

    # {{{ discretization

    if dim == 2:
        from meshmode.mesh.generation import make_curve_mesh, ellipse
        mesh = make_curve_mesh(
                lambda t: radius * ellipse(1.0, t),
                np.linspace(0.0, 1.0, resolution + 1),
                order)
    elif dim == 3:
        from meshmode.mesh.generation import generate_icosphere
        mesh = generate_icosphere(radius, order=4 * order,
                uniform_refinement_rounds=resolution)
    else:
        raise ValueError("unsupported dimension")

    discr_tag_to_group_factory = {}
    if use_quad:
        qtag = dof_desc.DISCR_TAG_QUAD
    else:
        qtag = None

    from meshmode.discretization.poly_element import \
            default_simplex_group_factory, \
            QuadratureSimplexGroupFactory

    discr_tag_to_group_factory[dof_desc.DISCR_TAG_BASE] = \
        default_simplex_group_factory(base_dim=dim-1, order=order)

    if use_quad:
        discr_tag_to_group_factory[qtag] = \
            QuadratureSimplexGroupFactory(order=4*order)

    from grudge import DiscretizationCollection

    dcoll = DiscretizationCollection(
        actx, mesh,
        discr_tag_to_group_factory=discr_tag_to_group_factory
    )

    volume_discr = dcoll.discr_from_dd(dof_desc.DD_VOLUME)
    logger.info("ndofs:     %d", volume_discr.ndofs)
    logger.info("nelements: %d", volume_discr.mesh.nelements)

    # }}}

    # {{{ Surface advection operator

    # velocity field
    x = thaw(dcoll.nodes(), actx)
    c = make_obj_array([-x[1], x[0], 0.0])[:dim]

    def f_initial_condition(x):
        return x[0]

    from grudge.models.advection import SurfaceAdvectionOperator
    adv_operator = SurfaceAdvectionOperator(
        dcoll,
        c,
        flux_type=flux_type,
        quad_tag=qtag
    )

    u0 = f_initial_condition(x)

    def rhs(t, u):
        return adv_operator.operator(t, u)

    # check velocity is tangential
    from grudge.geometry import normal

    surf_normal = normal(actx, dcoll, dd=dof_desc.DD_VOLUME)

    error = op.norm(dcoll, c.dot(surf_normal), 2)
    logger.info("u_dot_n:   %.5e", error)

    # }}}

    # {{{ time stepping

    # FIXME: dt estimate is not necessarily valid for surfaces
    dt = actx.to_numpy(
        0.45 * adv_operator.estimate_rk4_timestep(actx, dcoll, fields=u0))
    nsteps = int(final_time // dt) + 1

    logger.info("dt:        %.5e", dt)
    logger.info("nsteps:    %d", nsteps)

    from grudge.shortcuts import set_up_rk4
    dt_stepper = set_up_rk4("u", dt, u0, rhs)
    plot = Plotter(actx, dcoll, order, visualize=visualize)

    norm_u = actx.to_numpy(op.norm(dcoll, u0, 2))

    step = 0

    event = dt_stepper.StateComputed(0.0, 0, 0, u0)
    plot(event, "fld-surface-%04d" % 0)

    if visualize and dim == 3:
        from grudge.shortcuts import make_visualizer
        vis = make_visualizer(dcoll)
        vis.write_vtk_file(
            "fld-surface-velocity.vtu",
            [
                ("u", c),
                ("n", surf_normal)
            ],
            overwrite=True
        )

        df = dof_desc.DOFDesc(FACE_RESTR_INTERIOR)
        face_discr = dcoll.discr_from_dd(df)
        face_normal = thaw(dcoll.normal(dd=df), actx)

        from meshmode.discretization.visualization import make_visualizer
        vis = make_visualizer(actx, face_discr)
        vis.write_vtk_file("fld-surface-face-normals.vtu", [
            ("n", face_normal)
            ], overwrite=True)

    for event in dt_stepper.run(t_end=final_time, max_steps=nsteps + 1):
        if not isinstance(event, dt_stepper.StateComputed):
            continue

        step += 1
        if step % 10 == 0:
            norm_u = actx.to_numpy(op.norm(dcoll, event.state_component, 2))
            plot(event, "fld-surface-%04d" % step)

        logger.info("[%04d] t = %.5f |u| = %.5e", step, event.t, norm_u)

        # NOTE: These are here to ensure the solution is bounded for the
        # time interval specified
        assert norm_u < 3
Пример #15
0
def main(ctx_factory, dim=2, order=4, product_tag=None, visualize=False):
    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue)

    # {{{ parameters

    # domain [0, d]^dim
    d = 1.0
    # number of points in each dimension
    npoints = 25
    # grid spacing
    h = d / npoints

    # cfl
    dt_factor = 1.0
    # finale time
    final_time = 0.5
    # time steps
    dt = dt_factor * h / order**2
    nsteps = int(final_time // dt) + 1
    dt = final_time / nsteps + 1.0e-15

    # flux
    flux_type = "upwind"
    # velocity field
    sym_x = sym.nodes(dim)
    if dim == 1:
        c = sym_x
    else:
        # solid body rotation
        c = flat_obj_array(np.pi * (d / 2 - sym_x[1]),
                           np.pi * (sym_x[0] - d / 2), 0)[:dim]

    # }}}

    # {{{ discretization

    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(a=(0, ) * dim,
                                      b=(d, ) * dim,
                                      npoints_per_axis=(npoints, ) * dim,
                                      order=order)

    from meshmode.discretization.poly_element import \
            QuadratureSimplexGroupFactory

    if product_tag:
        discr_tag_to_group_factory = {
            product_tag: QuadratureSimplexGroupFactory(order=4 * order)
        }
    else:
        discr_tag_to_group_factory = {}

    from grudge import DiscretizationCollection
    discr = DiscretizationCollection(
        actx,
        mesh,
        order=order,
        discr_tag_to_group_factory=discr_tag_to_group_factory)

    # }}}

    # {{{ symbolic operators

    # gaussian parameters
    source_center = np.array([0.5, 0.75, 0.0])[:dim]
    source_width = 0.05
    dist_squared = np.dot(sym_x - source_center, sym_x - source_center)

    def f_gaussian(x):
        return sym.exp(-dist_squared / source_width**2)

    def f_step(x):
        return sym.If(sym.Comparison(dist_squared, "<", (4 * source_width)**2),
                      1, 0)

    def u_bc(x):
        return 0.0

    from grudge.models.advection import VariableCoefficientAdvectionOperator
    op = VariableCoefficientAdvectionOperator(c,
                                              u_bc(sym.nodes(dim, BTAG_ALL)),
                                              quad_tag=product_tag,
                                              flux_type=flux_type)

    bound_op = bind(discr, op.sym_operator())
    u = bind(discr, f_gaussian(sym.nodes(dim)))(actx, t=0)

    def rhs(t, u):
        return bound_op(t=t, u=u)

    # }}}

    # {{{ time stepping

    from grudge.shortcuts import set_up_rk4
    dt_stepper = set_up_rk4("u", dt, u, rhs)
    plot = Plotter(actx, discr, order, visualize=visualize, ylim=[-0.1, 1.1])

    step = 0
    norm = bind(discr, sym.norm(2, sym.var("u")))
    for event in dt_stepper.run(t_end=final_time):
        if not isinstance(event, dt_stepper.StateComputed):
            continue

        if step % 10 == 0:
            norm_u = norm(u=event.state_component)
            plot(event, "fld-var-velocity-%04d" % step)

        step += 1
        logger.info("[%04d] t = %.5f |u| = %.5e", step, event.t, norm_u)
Пример #16
0
def main(ctx_factory, dim=2, order=4, visualize=False):
    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(
        queue,
        allocator=cl_tools.MemoryPool(cl_tools.ImmediateAllocator(queue)),
        force_device_scalars=True,
    )

    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(a=(-0.5, ) * dim,
                                      b=(0.5, ) * dim,
                                      nelements_per_axis=(20, ) * dim)

    dcoll = DiscretizationCollection(actx, mesh, order=order)

    def source_f(actx, dcoll, t=0):
        source_center = np.array([0.1, 0.22, 0.33])[:dcoll.dim]
        source_width = 0.05
        source_omega = 3
        nodes = thaw(dcoll.nodes(), actx)
        source_center_dist = flat_obj_array(
            [nodes[i] - source_center[i] for i in range(dcoll.dim)])
        return (np.sin(source_omega * t) * actx.np.exp(
            -np.dot(source_center_dist, source_center_dist) / source_width**2))

    x = thaw(dcoll.nodes(), actx)
    ones = dcoll.zeros(actx) + 1
    c = actx.np.where(np.dot(x, x) < 0.15, 0.1 * ones, 0.2 * ones)

    from grudge.models.wave import VariableCoefficientWeakWaveOperator
    from meshmode.mesh import BTAG_ALL, BTAG_NONE

    wave_op = VariableCoefficientWeakWaveOperator(dcoll,
                                                  c,
                                                  source_f=source_f,
                                                  dirichlet_tag=BTAG_NONE,
                                                  neumann_tag=BTAG_NONE,
                                                  radiation_tag=BTAG_ALL,
                                                  flux_type="upwind")

    fields = flat_obj_array(dcoll.zeros(actx),
                            [dcoll.zeros(actx) for i in range(dcoll.dim)])

    wave_op.check_bc_coverage(mesh)

    def rhs(t, w):
        return wave_op.operator(t, w)

    dt = 2 / 3 * wave_op.estimate_rk4_timestep(actx, dcoll, fields=fields)
    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    final_t = 1
    nsteps = int(final_t / dt) + 1

    logger.info("dt=%g nsteps=%d", dt, nsteps)

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(dcoll)

    step = 0

    def norm(u):
        return op.norm(dcoll, u, 2)

    from time import time
    t_last_step = time()

    if visualize:
        u = fields[0]
        v = fields[1:]
        vis.write_vtk_file(f"fld-var-propogation-speed-{step:04d}.vtu", [
            ("u", u),
            ("v", v),
            ("c", c),
        ])

    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1

            if step % 10 == 0:
                logger.info(f"step: {step} t: {time()-t_last_step} "
                            f"L2: {norm(u=event.state_component[0])}")
                if visualize:
                    vis.write_vtk_file(
                        f"fld-var-propogation-speed-{step:04d}.vtu", [
                            ("u", event.state_component[0]),
                            ("v", event.state_component[1:]),
                            ("c", c),
                        ])
            t_last_step = time()

            # NOTE: These are here to ensure the solution is bounded for the
            # time interval specified
            assert norm(u=event.state_component[0]) < 1
Пример #17
0
def test_convergence_advec(ctx_factory,
                           mesh_name,
                           mesh_pars,
                           op_type,
                           flux_type,
                           order,
                           visualize=False):
    """Test whether 2D advection actually converges"""

    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue)

    from pytools.convergence import EOCRecorder
    eoc_rec = EOCRecorder()

    for mesh_par in mesh_pars:
        if mesh_name == "segment":
            from meshmode.mesh.generation import generate_box_mesh
            mesh = generate_box_mesh([np.linspace(-1.0, 1.0, mesh_par)],
                                     order=order)

            dim = 1
            dt_factor = 1.0
        elif mesh_name == "disk":
            pytest.importorskip("meshpy")

            from meshpy.geometry import make_circle, GeometryBuilder
            from meshpy.triangle import MeshInfo, build

            geob = GeometryBuilder()
            geob.add_geometry(*make_circle(1))
            mesh_info = MeshInfo()
            geob.set(mesh_info)

            mesh_info = build(mesh_info, max_volume=mesh_par)

            from meshmode.mesh.io import from_meshpy
            mesh = from_meshpy(mesh_info, order=1)
            dim = 2
            dt_factor = 4
        elif mesh_name.startswith("rect"):
            dim = int(mesh_name[4:])
            from meshmode.mesh.generation import generate_regular_rect_mesh
            mesh = generate_regular_rect_mesh(a=(-0.5, ) * dim,
                                              b=(0.5, ) * dim,
                                              n=(mesh_par, ) * dim,
                                              order=4)

            if dim == 2:
                dt_factor = 4
            elif dim == 3:
                dt_factor = 2
            else:
                raise ValueError("dt_factor not known for %dd" % dim)

        else:
            raise ValueError("invalid mesh name: " + mesh_name)

        v = np.array([0.27, 0.31, 0.1])[:dim]
        norm_v = la.norm(v)

        def f(x):
            return sym.sin(10 * x)

        def u_analytic(x):
            return f(-v.dot(x) / norm_v + sym.var("t", sym.DD_SCALAR) * norm_v)

        from grudge.models.advection import (StrongAdvectionOperator,
                                             WeakAdvectionOperator)
        discr = DGDiscretizationWithBoundaries(actx, mesh, order=order)
        op_class = {
            "strong": StrongAdvectionOperator,
            "weak": WeakAdvectionOperator,
        }[op_type]
        op = op_class(v,
                      inflow_u=u_analytic(sym.nodes(dim, sym.BTAG_ALL)),
                      flux_type=flux_type)

        bound_op = bind(discr, op.sym_operator())

        u = bind(discr, u_analytic(sym.nodes(dim)))(actx, t=0)

        def rhs(t, u):
            return bound_op(t=t, u=u)

        if dim == 3:
            final_time = 0.1
        else:
            final_time = 0.2

        h_max = bind(discr, sym.h_max_from_volume(discr.ambient_dim))(actx)
        dt = dt_factor * h_max / order**2
        nsteps = (final_time // dt) + 1
        dt = final_time / nsteps + 1e-15

        from grudge.shortcuts import set_up_rk4
        dt_stepper = set_up_rk4("u", dt, u, rhs)

        last_u = None

        from grudge.shortcuts import make_visualizer
        vis = make_visualizer(discr, vis_order=order)

        step = 0

        for event in dt_stepper.run(t_end=final_time):
            if isinstance(event, dt_stepper.StateComputed):
                step += 1
                logger.debug("[%04d] t = %.5f", step, event.t)

                last_t = event.t
                last_u = event.state_component

                if visualize:
                    vis.write_vtk_file("fld-%s-%04d.vtu" % (mesh_par, step),
                                       [("u", event.state_component)])

        error_l2 = bind(discr,
                        sym.norm(2,
                                 sym.var("u") - u_analytic(sym.nodes(dim))))(
                                     t=last_t, u=last_u)
        logger.info("h_max %.5e error %.5e", h_max, error_l2)
        eoc_rec.add_data_point(h_max, error_l2)

    logger.info(
        "\n%s", eoc_rec.pretty_print(abscissa_label="h",
                                     error_label="L2 Error"))

    assert eoc_rec.order_estimate() > order
Пример #18
0
def main(ctx_factory,
         dim=2,
         order=4,
         use_quad=False,
         visualize=False,
         flux_type="upwind"):
    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(
        queue,
        allocator=cl_tools.MemoryPool(cl_tools.ImmediateAllocator(queue)),
        force_device_scalars=True,
    )

    # {{{ parameters

    # domain [0, d]^dim
    d = 1.0
    # number of points in each dimension
    npoints = 25

    # final time
    final_time = 1

    if use_quad:
        qtag = dof_desc.DISCR_TAG_QUAD
    else:
        qtag = None

    # }}}

    # {{{ discretization

    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(a=(0, ) * dim,
                                      b=(d, ) * dim,
                                      npoints_per_axis=(npoints, ) * dim,
                                      order=order)

    from meshmode.discretization.poly_element import \
            QuadratureSimplexGroupFactory

    if use_quad:
        discr_tag_to_group_factory = {
            qtag: QuadratureSimplexGroupFactory(order=4 * order)
        }
    else:
        discr_tag_to_group_factory = {}

    from grudge import DiscretizationCollection

    dcoll = DiscretizationCollection(
        actx,
        mesh,
        order=order,
        discr_tag_to_group_factory=discr_tag_to_group_factory)

    # }}}

    # {{{ advection operator

    # gaussian parameters

    def f_halfcircle(x):
        source_center = np.array([d / 2, d / 2, d / 2])[:dim]
        dist = x - source_center
        return ((0.5 + 0.5 * actx.np.tanh(500 *
                                          (-np.dot(dist, dist) + 0.4**2))) *
                (0.5 + 0.5 * actx.np.tanh(500 * (dist[0]))))

    def zero_inflow_bc(dtag, t=0):
        dd = dof_desc.DOFDesc(dtag, qtag)
        return dcoll.discr_from_dd(dd).zeros(actx)

    from grudge.models.advection import VariableCoefficientAdvectionOperator

    x = thaw(dcoll.nodes(), actx)

    # velocity field
    if dim == 1:
        c = x
    else:
        # solid body rotation
        c = flat_obj_array(np.pi * (d / 2 - x[1]), np.pi * (x[0] - d / 2),
                           0)[:dim]

    adv_operator = VariableCoefficientAdvectionOperator(
        dcoll,
        c,
        inflow_u=lambda t: zero_inflow_bc(BTAG_ALL, t),
        quad_tag=qtag,
        flux_type=flux_type)

    u = f_halfcircle(x)

    def rhs(t, u):
        return adv_operator.operator(t, u)

    dt = actx.to_numpy(
        adv_operator.estimate_rk4_timestep(actx, dcoll, fields=u))

    logger.info("Timestep size: %g", dt)

    # }}}

    # {{{ time stepping

    from grudge.shortcuts import set_up_rk4
    dt_stepper = set_up_rk4("u", dt, u, rhs)
    plot = Plotter(actx, dcoll, order, visualize=visualize, ylim=[-0.1, 1.1])

    step = 0
    for event in dt_stepper.run(t_end=final_time):
        if not isinstance(event, dt_stepper.StateComputed):
            continue

        if step % 10 == 0:
            norm_u = actx.to_numpy(op.norm(dcoll, event.state_component, 2))
            plot(event, "fld-var-velocity-%04d" % step)

        step += 1
        logger.info("[%04d] t = %.5f |u| = %.5e", step, event.t, norm_u)

        # NOTE: These are here to ensure the solution is bounded for the
        # time interval specified
        assert norm_u < 1
Пример #19
0
def main(ctx_factory, dim=2, order=4, visualize=False):
    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue)

    # {{{ parameters

    # domain [-d/2, d/2]^dim
    d = 1.0
    # number of points in each dimension
    npoints = 20
    # grid spacing
    h = d / npoints

    # cfl
    dt_factor = 2.0
    # final time
    final_time = 1.0
    # compute number of steps
    dt = dt_factor * h / order**2
    nsteps = int(final_time // dt) + 1
    dt = final_time / nsteps + 1.0e-15

    # velocity field
    c = np.array([0.5] * dim)
    norm_c = la.norm(c)
    # flux
    flux_type = "central"

    # }}}

    # {{{ discretization

    from meshmode.mesh.generation import generate_box_mesh
    mesh = generate_box_mesh(
        [np.linspace(-d / 2, d / 2, npoints) for _ in range(dim)], order=order)

    from grudge import DiscretizationCollection
    discr = DiscretizationCollection(actx, mesh, order=order)

    # }}}

    # {{{ symbolic operators

    def f(x):
        return sym.sin(3 * x)

    def u_analytic(x):
        t = sym.var("t", dof_desc.DD_SCALAR)
        return f(-np.dot(c, x) / norm_c + t * norm_c)

    from grudge.models.advection import WeakAdvectionOperator
    op = WeakAdvectionOperator(c,
                               inflow_u=u_analytic(sym.nodes(dim, BTAG_ALL)),
                               flux_type=flux_type)

    bound_op = bind(discr, op.sym_operator())
    u = bind(discr, u_analytic(sym.nodes(dim)))(actx, t=0)

    def rhs(t, u):
        return bound_op(t=t, u=u)

    # }}}

    # {{{ time stepping

    from grudge.shortcuts import set_up_rk4
    dt_stepper = set_up_rk4("u", dt, u, rhs)
    plot = Plotter(actx, discr, order, visualize=visualize, ylim=[-1.1, 1.1])

    norm = bind(discr, sym.norm(2, sym.var("u")))

    step = 0
    norm_u = 0.0
    for event in dt_stepper.run(t_end=final_time):
        if not isinstance(event, dt_stepper.StateComputed):
            continue

        if step % 10 == 0:
            norm_u = norm(u=event.state_component)
            plot(event, "fld-weak-%04d" % step)

        step += 1
        logger.info("[%04d] t = %.5f |u| = %.5e", step, event.t, norm_u)
Пример #20
0
def main(write_output=True, order=4):
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue)

    comm = MPI.COMM_WORLD
    num_parts = comm.Get_size()

    from meshmode.distributed import MPIMeshDistributor, get_partition_by_pymetis
    mesh_dist = MPIMeshDistributor(comm)

    if mesh_dist.is_mananger_rank():
        dims = 2
        from meshmode.mesh.generation import generate_regular_rect_mesh
        mesh = generate_regular_rect_mesh(a=(-0.5, ) * dims,
                                          b=(0.5, ) * dims,
                                          n=(16, ) * dims)

        print("%d elements" % mesh.nelements)

        part_per_element = get_partition_by_pymetis(mesh, num_parts)

        local_mesh = mesh_dist.send_mesh_parts(mesh, part_per_element,
                                               num_parts)

        del mesh

    else:
        local_mesh = mesh_dist.receive_mesh_part()

    discr = DGDiscretizationWithBoundaries(actx,
                                           local_mesh,
                                           order=order,
                                           mpi_communicator=comm)

    if local_mesh.dim == 2:
        dt = 0.04
    elif local_mesh.dim == 3:
        dt = 0.02

    source_center = np.array([0.1, 0.22, 0.33])[:local_mesh.dim]
    source_width = 0.05
    source_omega = 3

    sym_x = sym.nodes(local_mesh.dim)
    sym_source_center_dist = sym_x - source_center
    sym_t = sym.ScalarVariable("t")

    from grudge.models.wave import StrongWaveOperator
    from meshmode.mesh import BTAG_ALL, BTAG_NONE
    op = StrongWaveOperator(
        -0.1,
        discr.dim,
        source_f=(
            sym.sin(source_omega * sym_t) *
            sym.exp(-np.dot(sym_source_center_dist, sym_source_center_dist) /
                    source_width**2)),
        dirichlet_tag=BTAG_NONE,
        neumann_tag=BTAG_NONE,
        radiation_tag=BTAG_ALL,
        flux_type="upwind")

    from pytools.obj_array import flat_obj_array
    fields = flat_obj_array(discr.zeros(actx),
                            [discr.zeros(actx) for i in range(discr.dim)])

    # FIXME
    #dt = op.estimate_rk4_timestep(discr, fields=fields)

    op.check_bc_coverage(local_mesh)

    # print(sym.pretty(op.sym_operator()))
    bound_op = bind(discr, op.sym_operator())

    def rhs(t, w):
        return bound_op(t=t, w=w)

    dt_stepper = set_up_rk4("w", dt, fields, rhs)

    final_t = 10
    nsteps = int(final_t / dt)
    print("dt=%g nsteps=%d" % (dt, nsteps))

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(discr, vis_order=order)

    step = 0

    norm = bind(discr, sym.norm(2, sym.var("u")))

    from time import time
    t_last_step = time()

    rank = comm.Get_rank()

    for event in dt_stepper.run(t_end=final_t):
        if isinstance(event, dt_stepper.StateComputed):
            assert event.component_id == "w"

            step += 1

            print(step, event.t, norm(u=event.state_component[0]),
                  time() - t_last_step)
            if step % 10 == 0:
                vis.write_vtk_file(
                    "fld-wave-min-mpi-%03d-%04d.vtu" % (
                        rank,
                        step,
                    ), [
                        ("u", event.state_component[0]),
                        ("v", event.state_component[1:]),
                    ])
            t_last_step = time()
Пример #21
0
def main(ctx_factory, dim=2, order=4, product_tag=None, visualize=False):
    cl_ctx = ctx_factory()
    queue = cl.CommandQueue(cl_ctx)
    actx = PyOpenCLArrayContext(queue)

    # {{{ parameters

    # sphere radius
    radius = 1.0
    # sphere resolution
    resolution = 64 if dim == 2 else 1

    # cfl
    dt_factor = 2.0
    # final time
    final_time = np.pi

    # velocity field
    sym_x = sym.nodes(dim)
    c = make_obj_array([-sym_x[1], sym_x[0], 0.0])[:dim]
    # flux
    flux_type = "lf"

    # }}}

    # {{{ discretization

    if dim == 2:
        from meshmode.mesh.generation import make_curve_mesh, ellipse
        mesh = make_curve_mesh(lambda t: radius * ellipse(1.0, t),
                               np.linspace(0.0, 1.0, resolution + 1), order)
    elif dim == 3:
        from meshmode.mesh.generation import generate_icosphere
        mesh = generate_icosphere(radius,
                                  order=4 * order,
                                  uniform_refinement_rounds=resolution)
    else:
        raise ValueError("unsupported dimension")

    discr_tag_to_group_factory = {}
    if product_tag == "none":
        product_tag = None
    else:
        product_tag = dof_desc.DISCR_TAG_QUAD

    from meshmode.discretization.poly_element import \
            PolynomialWarpAndBlendGroupFactory, \
            QuadratureSimplexGroupFactory

    discr_tag_to_group_factory[dof_desc.DISCR_TAG_BASE] = \
        PolynomialWarpAndBlendGroupFactory(order)

    if product_tag:
        discr_tag_to_group_factory[product_tag] = \
            QuadratureSimplexGroupFactory(order=4*order)

    from grudge import DiscretizationCollection
    discr = DiscretizationCollection(
        actx, mesh, discr_tag_to_group_factory=discr_tag_to_group_factory)

    volume_discr = discr.discr_from_dd(dof_desc.DD_VOLUME)
    logger.info("ndofs:     %d", volume_discr.ndofs)
    logger.info("nelements: %d", volume_discr.mesh.nelements)

    # }}}

    # {{{ symbolic operators

    def f_initial_condition(x):
        return x[0]

    from grudge.models.advection import SurfaceAdvectionOperator
    op = SurfaceAdvectionOperator(c, flux_type=flux_type, quad_tag=product_tag)

    bound_op = bind(discr, op.sym_operator())
    u0 = bind(discr, f_initial_condition(sym_x))(actx, t=0)

    def rhs(t, u):
        return bound_op(actx, t=t, u=u)

    # check velocity is tangential
    sym_normal = sym.surface_normal(dim, dim=dim - 1,
                                    dd=dof_desc.DD_VOLUME).as_vector()
    error = bind(discr, sym.norm(2, c.dot(sym_normal)))(actx)
    logger.info("u_dot_n:   %.5e", error)

    # }}}

    # {{{ time stepping

    # compute time step
    h_min = bind(discr, sym.h_max_from_volume(discr.ambient_dim,
                                              dim=discr.dim))(actx)
    dt = dt_factor * h_min / order**2
    nsteps = int(final_time // dt) + 1
    dt = final_time / nsteps + 1.0e-15

    logger.info("dt:        %.5e", dt)
    logger.info("nsteps:    %d", nsteps)

    from grudge.shortcuts import set_up_rk4
    dt_stepper = set_up_rk4("u", dt, u0, rhs)
    plot = Plotter(actx, discr, order, visualize=visualize)

    norm = bind(discr, sym.norm(2, sym.var("u")))
    norm_u = norm(actx, u=u0)

    step = 0

    event = dt_stepper.StateComputed(0.0, 0, 0, u0)
    plot(event, "fld-surface-%04d" % 0)

    if visualize and dim == 3:
        from grudge.shortcuts import make_visualizer
        vis = make_visualizer(discr)
        vis.write_vtk_file("fld-surface-velocity.vtu",
                           [("u", bind(discr, c)(actx)),
                            ("n", bind(discr, sym_normal)(actx))],
                           overwrite=True)

        df = dof_desc.DOFDesc(FACE_RESTR_INTERIOR)
        face_discr = discr.connection_from_dds(dof_desc.DD_VOLUME, df).to_discr

        face_normal = bind(
            discr, sym.normal(df, face_discr.ambient_dim,
                              dim=face_discr.dim))(actx)

        from meshmode.discretization.visualization import make_visualizer
        vis = make_visualizer(actx, face_discr)
        vis.write_vtk_file("fld-surface-face-normals.vtu",
                           [("n", face_normal)],
                           overwrite=True)

    for event in dt_stepper.run(t_end=final_time, max_steps=nsteps + 1):
        if not isinstance(event, dt_stepper.StateComputed):
            continue

        step += 1
        if step % 10 == 0:
            norm_u = norm(actx, u=event.state_component)
            plot(event, "fld-surface-%04d" % step)

        logger.info("[%04d] t = %.5f |u| = %.5e", step, event.t, norm_u)

    plot(event, "fld-surface-%04d" % step)
Пример #22
0
def main(write_output=True, order=4):
    cl_ctx = cl.create_some_context()
    queue = cl.CommandQueue(cl_ctx)

    dim = 2

    from meshmode.mesh.generation import generate_regular_rect_mesh
    mesh = generate_regular_rect_mesh(a=(-0.5, -0.5),
                                      b=(0.5, 0.5),
                                      n=(20, 20),
                                      order=order)

    dt_factor = 4
    h = 1 / 20

    discr = DGDiscretizationWithBoundaries(cl_ctx, mesh, order=order)

    c = np.array([0.1, 0.1])
    norm_c = la.norm(c)

    flux_type = "central"

    def f(x):
        return sym.sin(3 * x)

    def u_analytic(x):
        return f(-np.dot(c, x) / norm_c + sym.var("t", sym.DD_SCALAR) * norm_c)

    from grudge.models.advection import WeakAdvectionOperator

    discr = DGDiscretizationWithBoundaries(cl_ctx, mesh, order=order)
    op = WeakAdvectionOperator(c,
                               inflow_u=u_analytic(sym.nodes(
                                   dim, sym.BTAG_ALL)),
                               flux_type=flux_type)

    bound_op = bind(discr, op.sym_operator())

    u = bind(discr, u_analytic(sym.nodes(dim)))(queue, t=0)

    def rhs(t, u):
        return bound_op(queue, t=t, u=u)

    final_time = 0.3

    dt = dt_factor * h / order**2
    nsteps = (final_time // dt) + 1
    dt = final_time / nsteps + 1e-15

    from grudge.shortcuts import set_up_rk4
    dt_stepper = set_up_rk4("u", dt, u, rhs)

    from grudge.shortcuts import make_visualizer
    vis = make_visualizer(discr, vis_order=order)

    step = 0

    for event in dt_stepper.run(t_end=final_time):
        if isinstance(event, dt_stepper.StateComputed):

            step += 1

            #print(step, event.t, norm(queue, u=event.state_component[0]))
            vis.write_vtk_file("fld-weak-%04d.vtu" % step,
                               [("u", event.state_component)])