v7.0.0

7.0.0 breaks the API in many places, and no aliases are kept. Read the breaking
items before upgrading.

Package layout and import time

• Front-ends leave Utilities (breaking, no alias): the viewers Matplotlib and
  PyVista move to EasyFEA.Viz, file formats to EasyFEA.IO, one module per format
  family (Gmsh, Medit, Ensight, PyVista, Paraview, Vizir, USD, GLTF).
  from EasyFEA import Matplotlib, PyVista, IO keeps working; Paraview, Vizir,
  USD and GLTF are read as IO.Paraview, ... and no longer imported from the root
  or EasyFEA.Utilities. import EasyFEA loads neither pyplot nor pyvista (issue #67).
• MeshIO is removed: Gmsh_to_EasyFEA/EasyFEA_to_Gmsh become
  IO.Gmsh.Load_mesh/Save_mesh, likewise for Medit and Ensight; the PyVista
  conversions and Surface_reconstruction move to IO.PyVista. The node-order tables
  are renamed _GMSH_ to _EASYFEA_ (DICT_EASYFEA_TO_VTK_INDEXES, ...) (issue #67).
• Meshes and geometries no longer draw: Geom.Plot and Geom.Plot_Geoms become
  Matplotlib.Plot_Geoms, Mesh.Get_Paired_Nodes loses plot (the drawing is
  Plot_Paired_Nodes in the Homog1 example), Mesher.Save_simu becomes
  IO.Gmsh.Save_simu (with its own openGmsh) and Tic.Plot_History becomes
  Matplotlib.Plot_Tic_History (issue #67).
• Matplotlib.Plot_Geoms and PyVista.Plot_Geoms take *geoms, each a geom or a list
  of geoms, so their options are keyword-only (breaking for a positional ax)
  (issue #67).
• A failed meshing no longer opens a window: the MeshError carries the geometries in
  .geoms, to draw with PyVista.Plot_Geoms(error.geoms) (issue #67).
• EasyFEA.BUILDING_GALLERY is replaced by the EASYFEA_BUILDING_GALLERY environment
  variable, read at call time: the flag set by docs/conf.py used to be read too early
  to take effect (issue #67).
• IO formats share one signature per capability (breaking), checked by mypy against
  the MeshSaver, MeshLoader and SimuSaver protocols:
  Save_mesh(mesh, folder, name, *, useBinary=None), Load_mesh(path) and
  Save_simu(simu, folder, N, *, results=()), which returns what it wrote (the .pvd,
  simu.pos, the folder of .glb/.usdz files, or the vizir4 command). Paraview's
  nodeFields becomes results; USD and GLTF Save_mesh take name instead of
  filename; Gmsh.Save_simu requires folder, samples N iterations and spells
  edgecolor. useBinary=None keeps each format's default, an unsupported value raises
  ValueError (Ensight is text only, USD and GLTF binary only) (issue #68).
• Matplotlib and PyVista share one signature per function (breaking), checked by
  mypy against the Viewer protocol: Plot, Plot_Mesh, Plot_Nodes,
  Plot_Elements, Plot_BoundaryConditions, Plot_Tags, Plot_Geoms, Movie_simu,
  Movie_func. One spelling per option, grouped as object (deformFactor), field
  (result, coef, nodeValues), colorbar (cmap, nColors, clim,
  colorbarTitle, plotColorbar, verticalColorbar), style (color, edgecolor,
  linewidth, alpha, plotMesh, plotNodes, nodeSize) and annotation (title,
  label, showId, showGrid, plotLegend, bounds). Renamed: Matplotlib lw,
  ncolors, colorbarLabel, facecolors, Movie_Simu, Plot_Geoms(name=); PyVista
  verticalColobar, show_grid, point_size, useLegend (now showId, inverted),
  Plot_Geoms(line_width=). After the leading arguments, options are keyword-only; ax
  and plotter stay backend options. Matplotlib.Movie_func(func, N, folder, ...)
  takes fig as an optional keyword; both Movie_simu and Movie_func take fps, by
  default 10 for a gif and 24 for a movie (Matplotlib used 30) (issue #68).
• The view covers everything drawn in a figure: a second Plot_* on the same ax or
  plotter no longer shrinks a 3D Matplotlib view to its own object, and PyVista refits
  its camera. bounds=(xmin, xmax, ymin, ymax, zmin, zmax) fixes the view; a PyVista
  movie keeps the view of its first frame (issue #68).
• Plot's extra keywords reach the backend's draw call, but its own spelling of a
  shared option (lw, line_width, n_colors, ...) raises ValueError (issue #68).
• import EasyFEA takes about 0.2 s instead of 0.9 s: pyplot, pyvista, pxr, petsc4py,
  meshio and scipy.optimize load on first use. Optional dependencies are detected with
  importlib.util.find_spec, without importing them (issue #66).

Constitutive laws

• FEM.Kinematics(groupElem, displacement, matrixType) replaces HyperElasticState
  (breaking). Every law reads the strain measures it needs from it, computed once
  and cached: elastic Compute_Sigma(kinematics) and Compute_Psi(kinematics) replace
  Calc_Epsilon_e_pg, Calc_Sigma_e_pg and Calc_Psi_e_pg; phase field
  Compute_Sigma(kinematics, d), Compute_C(kinematics, d) and
  Compute_psi(kinematics) replace Calc_Sigma_e_pg, Calc_C and Calc_psi_e_pg;
  hyperelastic Compute_W, Compute_dWde and Compute_d2Wde take a Kinematics;
  inelastic behaviors Integrate(kinematics, z, dt); beams Compute_Epsilon,
  Compute_InternalForces and Compute_Sigma(kinematics). A simulation's strain or
  stress is an FeArray on a single element group, {groupElem: FeArray} on several
  (issue #63).
• Elastic laws write only their 3D material-frame Kelvin C (breaking): _Elastic
  rotates it, reads Voigt input, applies the 2D hypotheses, inverts and caches. C and
  S are read-only, Set_C loses update_S, Anisotropic loses axis1/axis2, and
  the transversely isotropic and orthotropic axes are settable parameters. 3D
  Anisotropic honours useVoigtNotation, and a 2D Anisotropic with out-of-plane
  axes no longer gives a silently wrong C; Anisotropic.Walpole_Decomposition raises
  (issue #65).
• The Kelvin–Mandel helpers live in one module (breaking): Models keeps only
  Get_Pmat and Apply_Pmat. KelvinMandel_Matrix, Project_vector_to_matrix,
  Project_matrix_to_vector, Project_Kelvin, Result_strain_or_stress_field_e and
  Reshape_variable are removed (issue #65).
• Heterogeneous parameters on meshes with several element groups: one model per group,
  each in its own Term(..., groupElem=g) (see the how-to Create models) (issue #62).
• print(model) lists the declared parameters, including heterogeneous ones.
  HyperElastic.Available_Laws lists CiarletGeymonat and HolzapfelOgden. Beam E
  and v, and the per-branch parameters of Maxwell and Chaboche, reject arrays.

Finite element arrays

• One lift, FeArray.broadcast(value, Ne, nPg, tensor_shape) (breaking):
  tensor_shape is required, and a shape that does not fit raises instead of being
  guessed. asfearray(x, True), FeArray(x, broadcastFeArrays=True) and
  Models.Reshape_variable are removed (issue #64).
• A plain array in @ or TensorProd with an FeArray is a constant tensor at every
  point (it used to raise, or silently sum over Gauss points when nPg == n). Integer
  indexing on the element or Gauss axis returns a plain ndarray; Norm() without
  axis reduces over the tensor axes only (issue #64).

Fixes

• Get_Elements_Tag and Get_Nodes_Tag raise KeyError on an unknown tag instead of
  returning an empty array (breaking).
• Newton solves the problemType it was given, tolerates a zero first residual, raises
  on a NaN or infinite residual (superlu_dist used to crash) and on non-convergence
  under python -O.
• MPI partition: nodes are owned through main-dimension elements only, and ghosts come
  from every element touching an owned node.
• Phase field: the psi+ history is stored per element group on mixed meshes;
  lsq_linear is chosen in the damage solve; the unlisted Wdef_e result that crashed
  is dropped.
• Mesh.Merge keeps element and node tags; the Mesh.coord setter notifies observers;
  Get_Nodes_Point falls back on a distance tolerance; Get_normals rejects node index
  Nn.
• Paraview reads Ne from each iteration's mesh; GLTF and USD Save_simu check they
  were given a simulation; PyVista rotation arrows are drawn and normalised; the time
  unit is right at exact boundaries (60 s, 1 h).
• Type annotations across the package, and mypy now sees through the requires_* and
  rank0_only decorators.

Development

• make lint runs import-linter (pinned in the lint extra): a layers contract in
  pyproject.toml fails on a new upward import between
  Viz > IO > Simulations > Models > FEM > Geoms > Utilities; its ignore_imports (3
  left) may only shrink (issue #66).
• Tests run in parallel by default (pytest -n auto); the dev extra adds
  pytest-xdist.

Full Changelog: v6.0.0...v7.0.0