[10.1.0] - 2026-02-26

Changed

• Make Mesh.x, Mesh.y and Mesh.z writable.
• Use the pseudo-inverse instead of the inverse of the Hessian to calculate dx in ConstitutiveMaterial.optimize().
• Ignore NaN values in the observed data in ConstitutiveMaterial.optimize().

Fixed

• Fix the dimension of the top-level field returned from FieldContainer.merge(). Previously, the dimension was taken from the mesh. Now, it is taken from the first field of the first sub-field container.

What's Changed

• Make Mesh.x, Mesh.y and Mesh.z writable by @adtzlr in #1031
• Fix ConstitutiveMaterial.optimize() by @adtzlr in #1034
• Fix FieldContainer.merge() for scalar-valued fields by @adtzlr in #1037

Full Changelog: v10.0.0...v10.1.0

[10.0.0] - 2026-02-13

Added

• Add MaterialStrain(..., framework="small-strain") to select a framework. Default is "small-strain" (unchanged) but now "total-lagrange" and "co-rotational" are also supported. Note that framework="total-lagrange" will change the linear-elastic material model formulation to the Saint-Venant Kirchhoff material model formulation.
• Add MaterialStrain(..., symmetry=True) to enforce the returned stress and elasticity tensors to be (minor) symmetric. Default is True. symmetry=False will improve performance if the provided material returns symmetric tensors.
• Add the Ogden material model formulation also for the JAX-backend constitution.jax.models.hyperelastic.ogden.
• Add linear_elastic_viscoelastic(), a linear-elastic (deviatoric) viscoelastic material model formulation to be used in MaterialStrain.

Changed

• Don't enforce the returned elasticity tensor in MaterialStrain to be major-symmetric.
• Change the default output of the loadcases dof.uniaxial(), dof.shear() and dof.biaxial() to return the dict of boundary conditions, but deprecate this boundaries, loadcase = fem.dof.uniaxial(field, return_loadcase=None) (was boundaries, loadcase = fem.dof.uniaxial(field) before). The additional loadcase dict is now optional, boundaries, loadcase = fem.dof.uniaxial(field, return_loadcase=True) is required.
• Don't support iteration over a BoundaryDict. Use BoundaryDict.items() or BoundaryDict.values() instead.
• Change the default label value in Boundary.plot(label="Boundary Condition") (was label=None before). The fall-back to Boundary.name is removed.

Deprecated

• Deprecate bounds in dof.symmetry(field, bounds=None). Use new equivalent boundaries argument, dof.symmetry(field, boundaries=None).
• Deprecate boundaries, loadcase = fem.dof.uniaxial(field, return_loadcase=None). Use return_loadcase=True or return_loadcase=False in new code. return_loadcase=False will be the default value in 11.0.0.

Removed

• Remove deprecated SolidBodyGravity.
• Remove support for Python 3.9.
• Remove unused optional name argument in Boundary.

What's Changed

• Add framework argument to MaterialStrain by @adtzlr in #1018
• Enhance MaterialStrain(..., symmetry=True) by @adtzlr in #1019
• Add MaterialStrain(framework="co-rotational") by @adtzlr in #1020
• Simplify default return value of loadcases dof.uniaxial(), dof.shear() and dof.biaxial() by @adtzlr in #1022
• Make BoundaryDict non-iterable by @adtzlr in #1023
• Add the Ogden model also for JAX by @adtzlr in #1025
• Remove support for EOL Python 3.9 by @adtzlr in #1026
• Add linear_elastic_viscoelastic() by @adtzlr in #1027
• Remove name arg in Boundary by @adtzlr in #1029
• deprecate dof.uniaxial(..., return_loadcase=None) by @adtzlr in #1030

Full Changelog: v9.5.0...v10.0.0

[9.5.0] - 2025-11-05

Added

• Add a JOSS badge to README.md and change CITATION.cff to JOSS.
• Add the keyword Job.evaluate(tqdm="tqdm") and newtonrhapson(tqdm="tqdm") with additional options "auto" and "notebook". The tqdm-keyword allows to switch the tqdm-backend manually. Note that in a Jupyter console, a progress bar from tqdm.auto does not update.
• Add the hessian() method to the ArbitraryOrderLagrange element and also for BiQuadraticQuad and TriQuadraticHexahedron.
• Add mesh.subdivide() and Mesh.subdivide() to refine a mesh with quad, hexahedron, triangle or tetra cells.

Changed

• Change the recommended citation from Zenodo to JOSS in README.md.

Fixed

• Fix the XDMF output error if a global field in Job.evaluate(x0=field) is based on RegionVertex. Fall-back to a basic output with only points and default point-data.
• Fix the magnitude in PointLoad.plot() for 2d-models in 3d-space, e.g. for truss bodies. Use the max. distance per axis instead of the min. distance per axis for the base magnitude of the force arrow(s).
• Change the mask-argument of a Boundary from a boolean array to an array-like argument, which is converted to a boolean array internally. This will handle integer mask-arrays correctly.

What's Changed

• JOSS paper edits by @kyleniemeyer in #1002
• Add Job.evaluate(tqdm="auto") by @adtzlr in #1005
• Fix the XDMF output error for a global field based on RegionVertex by @adtzlr in #1007
• Switch to default tqdm-backend by @adtzlr in #1008
• Fix zero magnitude of force arrows in PointLoad.plot() by @adtzlr in #1010
• Fix mask-argument of Boundary for integer-based mask arrays by @adtzlr in #1014
• Add hessian-method to bi-/tri- quadratic quad/hexahedron by @adtzlr in #1016
• Add mesh.subdivide() by @adtzlr in #1017

New Contributors

• @kyleniemeyer made their first contribution in #1002

Full Changelog: v9.4.1...v9.5.0

[9.4.1] - 2025-09-27

Added

• Add the pyOpenSci peer reviewed badge.

What's Changed

• Add pyOpenSci peer-reviewed Badge by @adtzlr in #1000

Full Changelog: v9.4.0...v9.4.1

[9.4.0] - 2025-09-25

Added

• Add a method to checkpoint a current state of deformation, state = SolidBody.checkpoint() and a method to restore checkpoints, SolidBody.restore(state). This is implemented for SolidBody, SolidBodyNearlyIncompressible and FieldContainer.
• Add math.revolve_points(), to revolve only points instead of a Mesh. Previously, mesh.revolve(points, cells=None, cell_type=None, **kwargs)[0] had to be used.
• Add math.rotate_points(), to rotate only points instead of a Mesh. Previously, mesh.rotate(points, cells=None, cell_type=None, **kwargs)[0] had to be used.
• Add FieldContainer.revolve(), SolidBody.revolve() and SolidBodyNearlyIncompressible.revolve() to convert a axisymmetric field / solid body to a 3d field / solid body. Only implemented for the conversion of axisymmetric quads to hexahedrons. For top-level fields, a vertex-mesh is also supported.
• Add fields, x0 = FieldContainer.merge() to simplify the handling of multiple items (solid bodies). The top-level field container x0 must be used for boundary conditions and in Job.evaluate(x0=x0).
• Add a warning if FieldMixed() is called with axisymmetric=True or planestrain=True, more than one field n>1 and a given dim. This dimension is passed to the dual fields only.
• Add support for the conversion of quad9 to hexahedron27 element types in mesh.revolve() and mesh.expand().
• Add newtonrhapson.callback(dx, x, iteration, xnorm, fnorm, success) to provide a callback after each completed Newton iteration. This is available as Job.evaluate(callback=newton_callback), whereas a callback after each completed substep has to be provided in Job(callback=substep_callback).
• Add a flag to plot MPC and point load either on the deformed (default) or undeformed mesh-points, MultiPointConstraint.plot(..., deformed=True), MultiPointContact.plot(..., deformed=True), PointLoad.plot(..., deformed=True).
• Add math.svd() for the singular value decomposition of arrays with trailing axes.
• Add newtonrhapson(..., progress_bar=None) which re-uses an existing tqdm progress bar. If provided, this progress bar must be manually closed. If None and verbose is True, a new progress bar is created.

Changed

• Allow field containers to be included in the list of fields in FieldContainer(fields). If a field container is included, its sub-fields are unpacked.
• Set custom attributes by keyword-arguments in FieldContainer(fields, **kwargs).
• Show also the progress of Newton's method for Job.evaluate(verbose=True).
• Switch to tqdm.auto for better progress bars in Jupyter notebooks.

What's Changed

• Remove SolidBody._area_change by @adtzlr in #970
• Add checkpoint() and restore() methods for solid bodies and field containers by @adtzlr in #972
• Clear force and stiffness results in SolidBody.restore() by @adtzlr in #973
• Add math.revolve_points() by @adtzlr in #974
• Make restoring state variables optional by @adtzlr in #975
• Add math.rotate_points() by @adtzlr in #976
• Add SolidBody.revolve() to convert axisymmetric models to 3d by @adtzlr in #978
• Add fields, x0 = FieldContainer.merge() by @adtzlr in #980
• Enhance FieldContainer.merge() for FieldsMixed() by @adtzlr in #981
• Enhance FieldContainer.init(): Allow field-containers in addition to fields by @adtzlr in #982
• Add FieldContainer.revolve() by @adtzlr in #984
• Enhance mesh.revolve() and mesh.expand(): Add support for quad9 to hexahedron27 by @adtzlr in #985
• Replace logo and simplify readme by @adtzlr in #987
• Add newtonrhapson(..., callback=None) by @adtzlr in #989
• Tests: Enforce matplotlib.use("Agg") to avoid tcl-related errors by @adtzlr in #992
• Enhance MultiPointConstraint.plot(..., deformed=True) by @adtzlr in #993
• Add math.svd() by @adtzlr in #994
• Show a progress for Newton's method by @adtzlr in #996
• Enhance the progress monitoring of Newton's method by @adtzlr in #998
• Switch to tqdm.auto for better progress bars in Jupyter by @adtzlr in #999

Full Changelog: v9.3.0...v9.4.0

[9.3.0] - 2025-06-29

Added

• Add Mesh.add_points(points) to update the mesh with additional points.
• Add Mesh.clear_points_without_cells() to clear the list of points without cells (useful for center-points of multi-point constraints).
• Release FElupe on conda-forge, starting with v9.2.0.
• Add ConstitutiveMaterial.is_stable() which returns a boolean mask of stability for isotropic material model formulations. Note that this will require an additional volumetric part of the strain energy density function for hyperelastic material model formulations without a volumetric part.
• Add the linear-elastic material formulation constitution.LinearElastic1D() and a truss-body mechanics.TrussBody().
• Add RegionTruss with a truss element. This is a line element with a GaussLobatto(order=0) quadrature, i.e. with two quadrature points located at the boundaries.

Changed

• Change the required setuptools-version in the build-system table of pyproject.toml to match PEP639 (setuptools>=77.0.3).
• Change the labels to well-known labels for the URLs in pyproject.toml.
• Change the first return value of ViewMaterial.uniaxial(), ViewMaterial.planar(), ViewMaterial.biaxial(), ViewMaterialIncompressible.uniaxial(), ViewMaterialIncompressible.planar(), ViewMaterialIncompressible.biaxial() from the stretch to a list of all three principal stretches.

Fixed

• Fix the declaration of the (spdx identifier) license and license-file in pyproject.toml.
• Fix missing import of TriQuadraticHexahedron in the top-level namespace.
• Fix the path to docs/_static/logo_without_text.svg in docs/conf.py.
• Fix a typo in the docstring of MeshContainer.from_unstructured_grid().
• Fix CompositeMaterial for input lists of length 1.

What's Changed

• Add Mesh.add_points(points) and Mesh.clear_points_without_cells() by @adtzlr in #947
• Update license in pyproject.toml by @adtzlr in #954
• Make license-files more explicit in pyproject.toml by @adtzlr in #955
• pyproject.toml ensure PEP639 support by @adtzlr in #956
• Fix missing import of TriQuadraticHexahedron by @adtzlr in #958
• Fix the path to the logo in docs/conf.py by @adtzlr in #959
• Fix a typo in the docstring of MeshContainer.from_unstructured_grid() by @adtzlr in #960
• Enhance some docstrings (only minor changes) by @adtzlr in #961
• Docs: Use matplotlib-directive for plots by @adtzlr in #962
• Fix typo from seperated to separated by @tkoyama010 in #963
• Add ConstitutiveMaterial.is_stable() and fix CompositeMaterial by @adtzlr in #965
• Add mechanics.Truss and constitution.LinearElastic1D by @adtzlr in #966
• Add RegionTruss by @adtzlr in #967

Full Changelog: v9.2.0...v9.3.0

Added

• Add SolidBody.assemble.mass(density=1.0) and SolidBodyNearlyIncompressible.assemble.mass(density=1.0) to assemble the mass matrix.
• Add SolidBody.evaluate.stress(field) to evaluate the (first Piola-Kirchhoff) stress tensor (engineering stress in linear elasticity).
• Add a free-vibration modal analysis Step/Job FreeVibration(items, boundaries) with methods to evaluate FreeVibration.evaluate() and to extract field, frequency = FreeVibration.extract(n) its n-th result.
• Add Boundary.plot() to plot the points and prescribed directions of a boundary.
• Add BoundaryDict as a subclassed dict with methods to plot(), screenshot() and imshow().
• Add a new argument to apply a callable on the assembled vector/matrix of a solid body, SolidBody(..., apply=None). This may be used to sum the list of sub-blocks instead of stacking them together, SolidBody(..., block=False, apply=None). This is useful for mixed formulations where both the deformation gradient and the displacement values are required.
• Add support for non-symmetric bilinear mixed forms in IntegralForm.
• Add element.Element to the top-level package namespace.
• Raise a TypeError if a mesh container is used as the mesh-argument in a region. The error message explains that the container is not supported. A mesh must be used instead.
• Add the Vertex element formulation.
• Add a vertex-region RegionVertex.
• Add MeshContainer.as_vertex_mesh() to create a merged vertex mesh from the meshes of the mesh container.
• Add Field.from_mesh_container(container) to create a top-level field on a vertex mesh.
• Add GaussLobatto quadrature. The order-argument is equal to the 1d-sample points minus two. This ensures identical minimum order-arguments for Gauss-Legendre and Gauss-Lobatto schemes.

Changed

• The first Piola-Kirchhoff stress tensor is evaluated if ViewSolid(stress_type=None).
• Autodetect the stress-type in SolidBody.plot(name) from name.
• Enhance the hello_world(axisymmetric=False, planestrain=False, curve=False, xdmf=False, container=False) function with new arguments to customize the generated template script.
• Enhance Boundary with added support for multiaxial prescribed values.
• Enhance math.linsteps(..., values=0) with default values except for the column axis if axis is not None.
• Link all field-values to the values of the first field if no other field is given in FieldContainer.link().
• Change the default arguments from block=True to block=None in SolidBody.assemble.vector(block=None) and SolidBody.assemble.matrix(block=None) and define block on creation, SolidBody(..., block=True) instead.
• Integrate and assemble None-items in the fun-argument of IntegralForm. On integration, None is returned. None will be assembled to an emtpy sparse matrix.
• Enhance mesh.interpolate_line(mesh, xi, axis=None, ...) which by default uses a curve-progress variable when axis=None. The curve progress evaluation points xi must be within 0 <= xi <= 1.

Fixed

• Fix Boundary(..., mode="and") by ignoring any undefined axis.
• Fix tools.hello_world(planestrain=True) with the correct region RegionQuad for the plane-strain template.
• Fix the cells-array in RegionQuadraticQuadBoundary for midpoints of edges.
• Fix FieldContainer.plot() for regions without the shape-function gradients available.

Removed

• Remove the unused shape-argument in element.Element(shape). Adopt the arbitrary-lagrange element to use its own dim-argument. This simplifies the creation of custom finite element formulations.

What's Changed

• Add SolidBody.evaluate.mass(density=1.0) by @adtzlr in #906
• Add SolidBody.evaluate.stress() and autodetect the stress-type in SolidBody.plot(name) from name by @adtzlr in #908
• Add FreeVibration(items, boundaries) by @adtzlr in #909
• Enhance Boundary: Add support for multiaxial prescribed value-argument by @adtzlr in #912
• Add Boundary.plot() and fix Boundary(..., mode="and") by @adtzlr in #913
• Add BoundaryDict by @adtzlr in #915
• Add PointLoad.plot() by @adtzlr in #916
• Enhance math.linsteps(..., values=0.0) by @adtzlr in #917
• Enhance FieldContainer.link() by @adtzlr in #918
• Add SolidBody(..., block=True, apply=None) by @adtzlr in #920
• Enhance IntegralForm: Non-symmetric mixed forms and None by @adtzlr in #922
• Simplify init of base-class element.Element by @adtzlr in #924
• Fix hello_word(planestrain=True) by @adtzlr in #928
• Fix RegionQuadraticQuadBoundary by @adtzlr in #933
• Don't create a figure if error in umat.plot() by @adtzlr in #934
• Raise a TypeError if a container is used in a region by @adtzlr in #939
• Add MeshContainer.as_vertex_mesh() and Field.from_mesh_container() by @adtzlr in #940
• Fix FieldContainer.plot() for RegionVertex (no gradient available) by @adtzlr in #942
• Add GaussLobatto quadrature scheme by @adtzlr in #943
• Enhance mesh.interpolate_line(axis=None) by @adtzlr in #945
• Set version tag to 9.2.0 by @adtzlr in #946

Full Changelog: v9.1.0...v9.2.0

[9.1.0] - 2024-11-23

Added

• Add the hessian of the element shape functions for a quadratic quad element QuadraticQuad.hessian().
• Add the order-argument to FieldContainer.extract(order="C") as well as for Field, FieldAxisymmetric, FieldPlaneStrain to return C-contiguous arrays by default.
• Add an optional multiplier to Laplace(multiplier=1.0).
• Add optional keyword-arguments to math.transpose(**kwargs) to support optional out and order-keywords.
• Add the attribute RegionBoundary.tangents, which contains a list of tangent unit vectors. For quad cell-types the length of this list is one and for hexahedron cell-types it is of length two.
• Add math.inplane(A, vectors) to return the in-plane components of a symmetric tensor A, where the plane is defined by its standard unit vectors.
• Add constitution.jax.Hyperelastic as a feature-equivalent alternative to Hyperelastic with jax as backend.
• Add constitution.jax.Material(..., jacobian=None) with JAX as backend. A custom jacobian-callable may be passed to switch between forward- and backward-mode automatic differentiation.
• Add material models for JAX-based materials. Hyperelastic models available at constitution.jax.models.hyperelastic: extended_tube(), miehe_goektepe_lulei(), mooney_rivlin(), neo_hooke(), yeoh(), third_order_deformation(), van_der_waals(). Lagrange (stress-based) models available at constitution.jax.models.lagrange: morph(), morph_representative_directions().
• Add constitution.jax.total_lagrange(), constitution.jax.updated_lagrange() and constitution.jax.isochoric_volumetric_split() function decorators for the JAX hyperelastic material class.
• Add an optional keyword-argument Region.astype(copy=True) to modify the data types of the arrays of the region in-place if copy=False.
• Add FieldContainer.evaluate.right_cauchy_green_deformation() and math.right_cauchy_green_deformation(field) to evaluate the right Cauchy-Green deformation tensor.
• Add math.strain(field, C=None, ..., **kwargs) to use a given right Cauchy-Green deformation tensor for the evaluation of the strain tensor.
• Add the hyperelastic foam models storakers() and blatz_ko() for both AD-backends.
• Add the saint_venant_kirchhoff_orthotropic() hyperelastic model (tensortrax).

Changed

• Change default np.einsum(..., order="K") to np.einsum(..., order="C") in the methods of Field, FieldAxisymmetric, FieldPlaneStrain and FieldContainer.
• Change supported Python versions to 3.9 - 3.12.
• Change the dtype-argument in Region.astype(dtype) from an optional to a required argument.
• Make tensortrax an optional dependency (again). Now FElupe does only depend on NumPy and SciPy, all other extras are optional.

Fixed

• Fix the number of points for non-disconnected dual meshes. This reduces the assembled (sparse) vector- and matrix-shapes, which are defined on mixed-fields.
• Fix wrong results of ConstitutiveMaterial.plot() if any stretch is non-physical, i.e. lower or equal zero. This raises an error now.

Removed

• Remove the unused, deprecated aliases UserMaterial, UserMaterialStrain and UserMaterialHyperelastic.

What's Changed

• Add QuadraticQuad.hessian() by @adtzlr in #851
• Update issue templates by @adtzlr in #855
• Fix pyOpenSci basic checks by @adtzlr in #854
• Extract C-contiguous arrays by default from fields by @adtzlr in #856
• Add an optional multiplier in Laplace(multiplier=1.0) by @adtzlr in #864
• Add optional kwargs in math.transpose(**kwargs) by @adtzlr in #865
• Fix the number of points for non-disconnected dual-meshes by @adtzlr in #867
• Fix wrong result of ConstitutiveMaterial.plot() if any stretch <= 0 by @adtzlr in #872
• Add RegionBoundary.tangents and math.inplane() by @adtzlr in #873
• Add constitution.jax.Hyperelastic by @adtzlr in #876
• Group the constitution module by autodiff-backends by @adtzlr in #878
• Add felupe.constitution.autodiff.jax.Material by @adtzlr in #879
• Add morph() for JAX-based Material by @adtzlr in #880
• Simplify the constitution module by @adtzlr in #881
• Add Total-Lagrange and Updated-Lagrange decorators for JAX by @adtzlr in #883
• Add more JAX-based models by @adtzlr in #884
• Add isochoric_volumetric_split() for JAX-hyperelastic material by @adtzlr in #885
• Move constitution.jax.isochoric_volumetric_split() by @adtzlr in #887
• Add optional in-place cast Region.astype(dtype, copy=True) by @adtzlr in #888
• Make the examples run faster on CI/CD by @adtzlr in #890
• Add miehe_goektepe_lulei model for JAX by @adtzlr in #892
• Make tensortrax optional by @adtzlr in #894
• Test the import in an environment with no autodiff-backend present by @adtzlr in #895
• Enable jax.Hyperelastic(..., parallel=True) with jax.pmap on quadrature-points axis by @adtzlr in #896
• Update GitHub-Actions by @adtzlr in #897
• Add math-function for the right Cauchy-Green deformation tensor by @adtzlr in #898
• Add the Storåkers hyperelastic foam model by @adtzlr in #900
• Add the Blatz-Ko hyperelastic foam model by @adtzlr in #901
• Add the Van-der-Waals model for JAX by @adtzlr in #902
• Add more hyperelastic models by @adtzlr in #903
• Add constitution.lame_converter_orthotropic() by @adtzlr in #904
• Add an optional strain exponent for the SVK-material by @adtzlr in #905

Full Changelog: v9.0.0...v9.1.0

[9.0.0] - 2024-09-06

Added

• Add Region.astype(dtype=None) to copy and cast the region arrays to a specified type.
• Add Field(..., dtype=None) to cast the array with field values to a specified type.
• Add Field.extract(dtype=None) to cast the extracted field gradient/interpolated values to a specified type.
• Add hello_world() to print the lines of a minimal-working-example to the console.
• Add mesh.interpolate_line(mesh, xi, axis) to interpolate a line mesh. The attribute points_derivative holds the derivatives of the independent variable w.r.t. the dependent variable(s). The column of the independent variable is filled with zeros.
• Add optional keyword-argument SolidBody.assemble.matrix(block=True), also for SolidBody.assemble.vector(block=True) and the assemble-methods of SolidBodyNearlyIncompressible. If block=False, these methods will assemble a list of the upper-triangle sub block-vectors/-matrices instead of the combined block-vector/-matrix.
• Add SolidBodyForce as a replacement for SolidBodyGravity with more general keyword arguments ("values" instead of "gravity", "scale" instead of "density").
• Add Laplace to be used as user-material in a solid body. Works with scalar- and vector-valued fields.
• Add an optional mechanics.Assemble(..., multiplier=None) argument which is used in external items like SolidBodyForce, SolidBodyGravity and PointLoad and is applied in newtonrhapson(items, ...).
• Add a new submodule view which contains the View... classes like ViewSolid or ViewField, previously located at tools._plot.
• Add the grad- and hess-arguments to the reload()- and copy()-methods of a Region, i.e. Region.reload(grad=None, hess=None).
• Add LinearElasticOrthotropic.
• Add SolidBodyCauchyStress in addition to SolidBodyPressure.
• Add mesh.cell_types() which returns an object-array with cell-type mappings for FElupe and PyVista.
• Add MeshContainer.from_unstructured_grid(grid, dim=None, **kwargs) to create a mesh-container from an unstructured grid (PyVista).

Changed

• Change the internal initialization of field = Field(region, values=1, dtype=None) values from field.values = np.ones(shape) * values to field = np.full(shape, fill_value=values, dtype=dtype). This enforces field = Field(region, values=1) to return the gradient array with data-type int which was of type float before.
• Initialize empty matrices of SolidBodyForce, SolidBodyGravity and PointLoad with dtype=float.
• Don't multiply the assembled vectors of SolidBodyForce, SolidBodyGravity and PointLoad by -1.0. Instead, mechanics.Assemble(multiplier=-1.0) is used in the solid bodies.
• Change the visibility of the internal helpers mechanics.Assemble, mechanics.Evaluate and mechanics.Results from private to public.
• Import the assembly module to the global namespace.
• Isolate the submodules, i.e. a submodule only uses the public API of another submodule. If necessary, this will help to change one or more modules to a future extension package.
• Enforce contiguous arrays for the region shape-function and -gradient arrays h and dhdX. This recovers the integral-form assembly performance from v8.6.0.
• Make the private basis classes public (assembly.expression.Basis, assembly.expression.BasisField and assembly.expression.BasisArray) as especially their docstrings are useful to understand how a Basis is created on a field.
• Remove material parameter keyword-arguments in the function()-, gradient()- and hessian()-methods of the core constitutive material formulations. This removes the ability for temporary material parameters in LinearElastic(E=None, nu=0.3).gradient(x, E=1.0), use LinearElastic(E=1.0, nu=0.3).gradient(x) instead. This affects the material formulations LinearElastic, LinearElasticPlaneStrain, LinearElasticPlaneStress, LinearElasticLargeStrain, NeoHooke and NeoHookeCompressible. None is still supported for the material parameters of NeoHooke and NeoHookeCompressible.
• Remove LinearElasticPlaneStrain from the top-level package namespace because this should only be used with Field(region, dim=2). The preferred method is to use FieldPlaneStrain(region, dim=2) and the default LinearElastic. LinearElasticPlaneStrain remains available in constitution.LinearElasticPlaneStrain.
• Rename Mesh.as_pyvista() to Mesh.as_unstructured_grid() and add Mesh.as_pyvista() as alias.

Deprecated

• Deprecate SolidBodyGravity, SolidBodyForce should be used instead.

What's Changed

• Add Region.astype(dtype=None) and Field(..., dtype=None) by @adtzlr in #797
• Add hello_world() by @adtzlr in #799
• Add mesh.interpolate_line(mesh, xi, axis) by @adtzlr in #811
• Change the derivative storage in mesh.interpolate_line() by @adtzlr in #812
• Add optional SolidBody.assemble.matrix(block=False) by @adtzlr in #813
• Add SolidBodyForce and Laplace by @adtzlr in #814
• Add optional Assemble(multiplier=None) by @adtzlr in #817
• Change the visibility of the helpers in the mechanics-module from private to public by @adtzlr in #818
• Fix Ex.09: Take care of changed sign of external form items by @adtzlr in #820
• Add submodule view by @adtzlr in #823
• Enhance the imports of the quadrature submodule by @adtzlr in #824
• Enhance the imports of the mechanics submodule by @adtzlr in #825
• Enhance (isolate) the cross-imports between submodules by @adtzlr in #826
• Fix the assembly performance by @adtzlr in #828
• Test if region attribute arrays are C-contiguous by @adtzlr in #829
• Add an example for the third medium contact method by @adtzlr in #834
• Make the classes Basis, BasisField and BasisArray public by @adtzlr in #835
• Add hess argument to Region(hess=False) by @adtzlr in #836
• Add LinearElasticOrthotropic by @adtzlr in #840
• Add SolidBodyCauchyStress by @adtzlr in #842
• Remove temporary kwargs in core constitutive materials by @adtzlr in #843
• Don't import LinearElasticPlaneStrain in top-level package namespace by @adtzlr in #844
• Add felupe.mesh.cell_types() by @adtzlr in #846
• Add MeshContainer.from_unstructured_grid() by @adtzlr in #847
• Update README.md by @adtzlr in #850

Full Changelog: v8.8.0...v9.0.0

[8.8.0] - 2024-06-16

Added

• Add Region(uniform=False), a flag to invoke a reduced evaluation of the element shape functions and their gradients. If True, only the first cell is evaluated. This drastically speeds up linear-elasticity on uniform grid meshes (e.g. voxel-like quads and hexahedrons).
• Add an update-method in FormItem(..., ramp_item=0).update(value). This enables a FormItem to be used as a ramped-item in a Step.

What's Changed

• Add Region(uniform=False): A performance feature for uniform grid meshes by @adtzlr in #792
• Add FormItem().update(values) by @adtzlr in #796

Full Changelog: v8.7.0...v8.8.0