test_refinement.py

from __future__ import division, absolute_import, print_function

__copyright__ = "Copyright (C) 2014-6 Shivam Gupta, Andreas Kloeckner"

__license__ = """
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""

import logging
from functools import partial

import pytest
import pyopencl as cl
import pyopencl.clmath  # noqa

import numpy as np
from pyopencl.tools import (  # noqa
        pytest_generate_tests_for_pyopencl
        as pytest_generate_tests)
from meshmode.mesh.generation import (  # noqa
        generate_icosahedron, generate_box_mesh, make_curve_mesh, ellipse)
from meshmode.mesh.refinement.utils import check_nodal_adj_against_geometry
from meshmode.mesh.refinement import Refiner, RefinerWithoutAdjacency

from meshmode.discretization.poly_element import (
    InterpolatoryQuadratureSimplexGroupFactory,
    PolynomialWarpAndBlendGroupFactory,
    PolynomialEquidistantSimplexGroupFactory,
)

logger = logging.getLogger(__name__)


def get_blob_mesh(mesh_par, order=4):
    # from meshmode.mesh.io import generate_gmsh, FileSource
    # return generate_gmsh(
    #         FileSource("blob-2d.step"), 2, order=order,
    #         force_ambient_dim=2,
    #         other_options=[
    #             "-string", "Mesh.CharacteristicLengthMax = %s;" % mesh_par]
    #         )

    from meshmode.mesh.io import read_gmsh
    return read_gmsh(
            "blob2d-order%d-h%s.msh" % (order, mesh_par),
            force_ambient_dim=2)


def random_refine_flags(fract, mesh):
    all_els = list(range(mesh.nelements))

    flags = np.zeros(mesh.nelements)
    from random import shuffle, seed
    seed(17)
    shuffle(all_els)
    for i in range(int(mesh.nelements * fract)):
        flags[all_els[i]] = 1

    return flags


def even_refine_flags(spacing, mesh):
    flags = np.zeros(mesh.nelements)
    flags[::spacing] = 1
    return flags


def empty_refine_flags(mesh):
    return np.zeros(mesh.nelements)


def uniform_refine_flags(mesh):
    return np.ones(mesh.nelements)


@pytest.mark.parametrize(("case_name", "mesh_gen", "flag_gen", "num_generations"), [
    # Fails?
    # ("icosahedron",
    #     partial(generate_icosahedron, 1, order=1),
    #     partial(random_refine_flags, 0.4),
    #     3),

    ("3_to_1_ellipse_unif",
        partial(
            make_curve_mesh,
            partial(ellipse, 3),
            np.linspace(0, 1, 21),
            order=1),
        uniform_refine_flags,
        4),

    ("rect2d_rand",
        partial(generate_box_mesh, (
            np.linspace(0, 1, 3),
            np.linspace(0, 1, 3),
            ), order=1),
        partial(random_refine_flags, 0.4),
        4),

    ("rect2d_unif",
        partial(generate_box_mesh, (
            np.linspace(0, 1, 2),
            np.linspace(0, 1, 2),
            ), order=1),
        uniform_refine_flags,
        3),

    ("blob2d_rand",
        partial(get_blob_mesh, "6e-2", order=1),
        partial(random_refine_flags, 0.4),
        4),

    ("rect3d_rand",
        partial(generate_box_mesh, (
            np.linspace(0, 1, 2),
            np.linspace(0, 1, 3),
            np.linspace(0, 1, 2),
            ), order=1),
        partial(random_refine_flags, 0.4),
        3),

    ("rect3d_unif",
        partial(generate_box_mesh, (
            np.linspace(0, 1, 2),
            np.linspace(0, 1, 2)), order=1),
        uniform_refine_flags,
        3),
    ])
def test_refinement(case_name, mesh_gen, flag_gen, num_generations):
    from random import seed
    seed(13)

    mesh = mesh_gen()

    r = Refiner(mesh)

    for _ in range(num_generations):
        flags = flag_gen(mesh)
        mesh = r.refine(flags)

        check_nodal_adj_against_geometry(mesh)


@pytest.mark.parametrize("refiner_cls", [
    Refiner,
    RefinerWithoutAdjacency
    ])
@pytest.mark.parametrize("group_factory", [
    InterpolatoryQuadratureSimplexGroupFactory,
    PolynomialWarpAndBlendGroupFactory,
    PolynomialEquidistantSimplexGroupFactory
    ])
@pytest.mark.parametrize(("mesh_name", "dim", "mesh_pars"), [
    ("circle", 1, [20, 30, 40]),
    ("blob", 2, ["8e-2", "6e-2", "4e-2"]),
    ("warp", 2, [4, 5, 6]),
    ("warp", 3, [4, 5, 6]),
])
@pytest.mark.parametrize("mesh_order", [1, 4, 5])
@pytest.mark.parametrize("refine_flags", [
    # FIXME: slow
    #uniform_refine_flags,
    #partial(random_refine_flags, 0.4)
    partial(even_refine_flags, 2)
])
# test_refinement_connection(cl._csc, RefinerWithoutAdjacency, PolynomialWarpAndBlendGroupFactory, 'warp', 2, [4, 5, 6], 5, partial(even_refine_flags, 2))  # noqa: E501
def test_refinement_connection(
        ctx_getter, refiner_cls, group_factory,
        mesh_name, dim, mesh_pars, mesh_order, refine_flags, visualize=False):
    from random import seed
    seed(13)

    # Discretization order
    order = 5

    cl_ctx = ctx_getter()
    queue = cl.CommandQueue(cl_ctx)

    from meshmode.discretization import Discretization
    from meshmode.discretization.connection import (
            make_refinement_connection, check_connection)

    from pytools.convergence import EOCRecorder
    eoc_rec = EOCRecorder()

    for mesh_par in mesh_pars:
        # {{{ get mesh

        if mesh_name == "circle":
            assert dim == 1
            h = 1 / mesh_par
            mesh = make_curve_mesh(
                partial(ellipse, 1), np.linspace(0, 1, mesh_par + 1),
                order=mesh_order)
        elif mesh_name == "blob":
            if mesh_order == 5:
                pytest.xfail("https://gitlab.tiker.net/inducer/meshmode/issues/2")
            assert dim == 2
            mesh = get_blob_mesh(mesh_par, mesh_order)
            h = float(mesh_par)
        elif mesh_name == "warp":
            from meshmode.mesh.generation import generate_warped_rect_mesh
            mesh = generate_warped_rect_mesh(dim, order=mesh_order, n=mesh_par)
            h = 1/mesh_par
        else:
            raise ValueError("mesh_name not recognized")

        # }}}

        from meshmode.mesh.processing import find_bounding_box
        mesh_bbox_low, mesh_bbox_high = find_bounding_box(mesh)
        mesh_ext = mesh_bbox_high-mesh_bbox_low

        def f(x):
            result = 1
            if mesh_name == "blob":
                factor = 15
            else:
                factor = 9

            for iaxis in range(len(x)):
                result = result * cl.clmath.sin(factor * (x[iaxis]/mesh_ext[iaxis]))

            return result

        discr = Discretization(cl_ctx, mesh, group_factory(order))

        refiner = refiner_cls(mesh)
        flags = refine_flags(mesh)
        refiner.refine(flags)

        connection = make_refinement_connection(
            refiner, discr, group_factory(order))
        check_connection(connection)

        fine_discr = connection.to_discr

        x = discr.nodes().with_queue(queue)
        x_fine = fine_discr.nodes().with_queue(queue)
        f_coarse = f(x)
        f_interp = connection(queue, f_coarse).with_queue(queue)
        f_true = f(x_fine).with_queue(queue)

        if visualize == "dots":
            import matplotlib.pyplot as plt
            x = x.get(queue)
            err = np.array(np.log10(
                1e-16 + np.abs((f_interp - f_true).get(queue))), dtype=float)
            import matplotlib.cm as cm
            cmap = cm.ScalarMappable(cmap=cm.jet)
            cmap.set_array(err)
            plt.scatter(x[0], x[1], c=cmap.to_rgba(err), s=20, cmap=cmap)
            plt.colorbar(cmap)
            plt.show()

        elif visualize == "vtk":
            from meshmode.discretization.visualization import make_visualizer
            fine_vis = make_visualizer(queue, fine_discr, mesh_order)

            fine_vis.write_vtk_file(
                    "refine-fine-%s-%dd-%s.vtu" % (mesh_name, dim, mesh_par), [
                        ("f_interp", f_interp),
                        ("f_true", f_true),
                        ])

        import numpy.linalg as la
        err = la.norm((f_interp - f_true).get(queue), np.inf)
        eoc_rec.add_data_point(h, err)

    order_slack = 0.5
    if mesh_name == "blob" and order > 1:
        order_slack = 1

    print(eoc_rec)
    assert (
            eoc_rec.order_estimate() >= order-order_slack
            or eoc_rec.max_error() < 1e-14)


@pytest.mark.parametrize("with_adjacency", [True, False])
def test_uniform_refinement(with_adjacency):
    make_mesh = partial(generate_box_mesh, (
            np.linspace(0.0, 1.0, 2),
            np.linspace(0.0, 1.0, 3),
            np.linspace(0.0, 1.0, 2)), order=4)
    mesh = make_mesh()

    from meshmode.mesh.refinement import refine_uniformly
    mesh = refine_uniformly(mesh, 1, with_adjacency=with_adjacency)


@pytest.mark.parametrize("refinement_rounds", [0, 1, 2])
def test_conformity_of_uniform_mesh(refinement_rounds):
    from meshmode.mesh.generation import generate_icosphere
    mesh = generate_icosphere(r=1.0, order=4,
            uniform_refinement_rounds=refinement_rounds)

    assert mesh.is_conforming

    from meshmode.mesh import is_boundary_tag_empty, BTAG_ALL
    assert is_boundary_tag_empty(mesh, BTAG_ALL)


if __name__ == "__main__":
    import sys
    if len(sys.argv) > 1:
        exec(sys.argv[1])
    else:
        from pytest import main
        main([__file__])

# vim: fdm=marker