Felupe

Changed
- Change the logo.

Added
- Add `ViewMesh(mesh)` and rebase `View` (internally renamed to `ViewField`) on `ViewMesh` with additional point- and cell-data.

Changed
- Change `math.linsteps(axis=None, axes=None)` to create optional multi-column arrays, where the steps are inserted at the given `axis`.
- Make last `gravity` and `density` arguments of `SolidBodyGravity(field, gravity=None, density=1.0)` optional.

Changed
- Show a progress bar during `Job.evaluate(verbose=True)` (new optional dependency `tqdm`). The legacy detailed output is available with `Job.evaluate(verbose=2)`.

Removed
- Remove config files for MyBinder. They are now located in a different repository [adtzlr/felupe-web](https://github.com/adtzlr/felupe-web).

Added
- Add `environment.yml` config file for [MyBinder](https://mybinder.org/).
- Add a timetrack-list as `Job.timetrack` which is updated incrementally on `Job.evaluate()`.
- Add `View(field, point_data=None, cell_data=None)`, a result plotter powered by [`pyvista`](https://github.com/pyvista/pyvista).
- Add `ViewXdmf(filename, time=0)`, a result plotter powered by [`pyvista`](https://github.com/pyvista/pyvista).

Changed
- Make everything in `/src` compliant with [flake8](https://flake8.pycqa.org/).
- Generalize the math-module so that all functions handle an arbitrary number of elementwise-operating trailing axes.
- The special contraction modes of `math.dot(mode=(2,2))` and `math.ddot(mode=(2,2))` have to be specified by the `mode`-argument and are not detected by the shapes of the operands.
- Enhance the overall performance by enforcing the identity matrix to a C-contiguous array.
- Change point- and cell-data functions used in `Job.evaluate(point_data=None, cell_data=None)` from `fun(substep)` to `fun(field, substep)`.

Fixed
- Fix timings shown in `newtonrhapson(verbose=True)`: The solve time was only related to one call of the solver while the assembly time referred to the whole runtime subtracted by the single-call solve time.

Added
- Add string representations for `Region` and `FieldContainer.`
- Add `Job.evaluate(parallel=True)` in addition to `Job.evaluate(kwargs={"parallel": True})`. If both are given, the key in the dict is overwritten by the user-defined value.
- Add `mesh.stack(meshes)` for joining meshes with identical points-arrays and cell-types. Contrary to `mesh.concatenate(meshes)`, the points are not stacked and no offsets are inserted into the cells-arrays.
- Add `mesh.translate(move, axis)` for the translation of mesh-points.

Changed
- Pass optional keyword-arguments in `CharacteristicCurve.plot(**kwargs)` to the figure.
- Don't invoke `CharacteristicCurve.evaluate()` from `CharacteristicCurve.plot()`, raise an error if the current job is not evaluated instead.
- Make the endpoint of `math.linsteps(endpoint=True)` optional.
- Don't modify the mesh for the dual regions `RegionConstantQuad()` and `RegionConstantHexahedron()`. Instead, it is required to pass a dual (disconnected) mesh with one point per cell `RegionConstantQuad(mesh.dual(points_per_cell=1))`.
- Make requirement `einsumt` optional again due to issues with JupyterLite.
- Add `matplotlib` to optional requirements.

Fixed
- Catch `ModuleNotFoundError` if `from einsumt import einsumt` fails (in JupyterLite) and fall back to `from numpy import einsum as einsumt`.

Added
- Add boundary regions `RegionQuadraticQuadBoundary` and `RegionBiQuadraticQuadBoundary` for quadratic quads.
- Add boundary regions `RegionQuadraticHexahedronBoundary` and `RegionTriQuadraticHexahedronBoundary` for quadratic hexahedrons.
- Add `mesh.flip(mask=None)` to flip a mirrored or wrong indexed cells array, applied on a given boolean `mask` of cells.

Changed
- Change `einsumt` from an optional to a required dependency.
- Vectorize implementations of `MultiPointConstraint` and `MultiPointContact` and re-implement both as `scipy.sparse.lil_matrix()`.
- Rename old `Mesh` to `DiscreteGeometry` and rebase new `Mesh` on `DiscreteGeometry`.
- Simplify the usage of explicit mesh-related tools by adding them as methods to `Mesh`, i.e. `mesh.tools.expand(Rectangle())` is equivalent to `Rectangle().expand()`.
- Print runtimes for time spent on Assembly and Solve in `newtonrhapson(verbose=True)`.
- Check for negative cell-volumes at quadrature points and print a warning along with a possible fix.

Fixed
- Fix `tools.project()` for higher-order quad- and hexahedron elements.
- Fix transposed output of `tools.project()`.
- Fix failed scalar-value checks by using `np.isscalar()` in `mesh.expand(z=1)` and `mesh.revolve(phi=180)` where `z` or `phi` are of type `np.int32`.
- Fix read a Mesh with no cells in `mesh.read()`.

Removed
- Remove `jit`-compilation of forms (`parallel` is the preferred method).
- Remove unused `tools.check()`.
- Remove optional dependency `sparse`.