__copyright__ = "Copyright (C) 2007 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.
"""


"Maxwell's equation example with fixed material coefficients"


from __future__ import division
from __future__ import absolute_import
from __future__ import print_function
import numpy.linalg as la


def main(write_output=True):
    from math import sqrt, pi, exp
    from os.path import join

    from grudge.backends import guess_run_context
    rcon = guess_run_context()

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

    output_dir = "maxwell-2d"
    import os
    if not os.access(output_dir, os.F_OK):
        os.makedirs(output_dir)

    from grudge.mesh.generator import make_disk_mesh
    mesh = make_disk_mesh(r=0.5, max_area=1e-3)

    if rcon.is_head_rank:
        mesh_data = rcon.distribute_mesh(mesh)
    else:
        mesh_data = rcon.receive_mesh()

    class CurrentSource:
        shape = (3,)

        def __call__(self, x, el):
            return [0,0,exp(-80*la.norm(x))]

    order = 3
    final_time = 1e-8
    discr = rcon.make_discretization(mesh_data, order=order,
            debug=["cuda_no_plan"])

    from grudge.visualization import VtkVisualizer
    if write_output:
        vis = VtkVisualizer(discr, rcon, join(output_dir, "em-%d" % order))

    if rcon.is_head_rank:
        print("order %d" % order)
        print("#elements=", len(mesh.elements))

    from grudge.mesh import BTAG_ALL, BTAG_NONE
    from grudge.models.em import TMMaxwellOperator
    from grudge.data import make_tdep_given, TimeIntervalGivenFunction
    op = TMMaxwellOperator(epsilon, mu, flux_type=1,
            current=TimeIntervalGivenFunction(
                make_tdep_given(CurrentSource()), off_time=final_time/10),
            absorb_tag=BTAG_ALL, pec_tag=BTAG_NONE)
    fields = op.assemble_eh(discr=discr)

    from grudge.timestep import LSRK4TimeStepper
    stepper = LSRK4TimeStepper()
    from time import time
    last_tstep = time()
    t = 0

    # diagnostics setup ---------------------------------------------------
    from logpyle import LogManager, add_general_quantities, \
            add_simulation_quantities, add_run_info

    if write_output:
        log_file_name = join(output_dir, "maxwell-%d.dat" % order)
    else:
        log_file_name = None

    logmgr = LogManager(log_file_name, "w", rcon.communicator)
    add_run_info(logmgr)
    add_general_quantities(logmgr)
    add_simulation_quantities(logmgr)
    discr.add_instrumentation(logmgr)
    stepper.add_instrumentation(logmgr)

    from logpyle import IntervalTimer
    vis_timer = IntervalTimer("t_vis", "Time spent visualizing")
    logmgr.add_quantity(vis_timer)

    from grudge.log import EMFieldGetter, add_em_quantities
    field_getter = EMFieldGetter(discr, op, lambda: fields)
    add_em_quantities(logmgr, op, field_getter)

    logmgr.add_watches(["step.max", "t_sim.max",
        ("W_field", "W_el+W_mag"), "t_step.max"])

    # timestep loop -------------------------------------------------------
    rhs = op.bind(discr)

    try:
        from grudge.timestep import times_and_steps
        step_it = times_and_steps(
                final_time=final_time, logmgr=logmgr,
                max_dt_getter=lambda t: op.estimate_timestep(discr,
                    stepper=stepper, t=t, fields=fields))

        for step, t, dt in step_it:
            if step % 10 == 0 and write_output:
                e, h = op.split_eh(fields)
                visf = vis.make_file(join(output_dir, "em-%d-%04d" % (order, step)))
                vis.add_data(visf,
                        [
                            ("e", discr.convert_volume(e, "numpy")),
                            ("h", discr.convert_volume(h, "numpy")),
                            ],
                        time=t, step=step
                        )
                visf.close()

            fields = stepper(fields, t, dt, rhs)

        assert discr.norm(fields) < 0.03
    finally:
        if write_output:
            vis.close()

        logmgr.close()
        discr.close()

if __name__ == "__main__":
    import cProfile as profile
    #profile.run("main()", "wave2d.prof")
    main()




# entry points for py.test ----------------------------------------------------
from pytools.test import mark_test
@mark_test.long
def test_maxwell_2d():
    main(write_output=False)