#!/usr/bin/env python
# *-* coding: utf-8 *-*
"""
Creating meshes with the mesh_gen object
========================================

There is a new (2026) interface to  :py:mod:`cr_trig_create`,
:py:class:`crtomo.mesh_interface.CRTomoGMSHMeshGenerator`.

This example present various ways to use this generator class.

.. note::

    You can access the generator class in two ways: ``from
    crtomo.mesh_interface import CRTomoGMSHMeshGenerator`` or using the
    top-level module ``crtomo``: ``from crtomo import
    CRTomoGMSHMeshGenerator``. There is also an already initialized instance of
    the mesh loaded as ``crtomo.mesh_gen``. In most cases, this instance is the
    easiest way to use the generator.

"""
###############################################################################
# The top level crtomo import suffices for most tasks
import crtomo
import numpy as np
###############################################################################
# Defining the mesh boundaries and electrode positions
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
# .. note::
#
#   Always work clockwise when denoting boundary nodes!
#

# define the electrode positions
electrodes = np.array((
    (0, 0),
    (1, 0),
    (2, 0),
    (3, 0),
))

# define the boundary geometry
# the last number indicates the type of boundary element towards the next node
# 12: Neumann no-flow boundaries (for surface boundaries)
# 11: mixed boundary types (subsurface boundaries)
boundaries = np.array((
    (-1, 0, 12),
    (0, 0, 12),
    (1, 0, 12),
    (2, 0, 12),
    (3, 0, 12),
    (4, 0, 11),
    (4, -2, 11),
    (-1, -2, 11),
))
###############################################################################
# Mesh Generation
# ^^^^^^^^^^^^^^^
mesh = crtomo.mesh_gen.gen_mesh(
    boundaries,
    electrodes,
    char_lengths=[
        0.5,
        0.45,
        0.45,
        0.45,
    ],
)
_ = mesh.plot()