ChangeLog.md

Changelog

2021.1.0

• Mixed dimensional domain support

2019.1.0 (2019-04-17)

• Remove scripts
• Remove LaTeX support (not functional)
• Add support for complex valued elements; complex mode is chosen by compute_form_data(form, complex_mode=True) typically by a form compiler; otherwise UFL language is agnostic to the choice of real/complex domain

2018.1.0 (2018-06-14)

• Remove python2 support

2017.2.0 (2017-12-05)

• Add geometric quantity CellDiameter defined as a set diameter of the cell, i.e., maximal distance between any two points of the cell; implemented on simplices and quads/hexes
• Rename internally used reference quantities (Cell|Facet)EdgeVectors to Reference(Cell|Facet)EdgeVectors
• Add internally used quantites CellVertices, (Cell|Facet)EdgeVectors which are physical-coordinates-valued; will be useful for further geometry lowering implementations for quads/hexes
• Implement geometry lowering of (Min|Max)(Cell|Facet)EdgeLength for quads and hexes

2017.1.0.post1 (2017-09-12)

• Change PyPI package name to fenics-ufl.

2017.1.0 (2017-05-09)

• Add the DirectionalSobolevSpace subclass of SobolevSpace. This allows one to use spaces where elements have varying continuity in different spatial directions.
• Add sobolev_space methods for HDiv and HCurl finite elements.
• Add sobolev_space methods for TensorProductElement and EnrichedElement. The smallest shared Sobolev space will be returned for enriched elements. For the tensor product elements, a DirectionalSobolevSpace is returned depending on the order of the spaces associated with the component elements.

2016.2.0 (2016-11-30)

• Add call operator syntax to Form to replace arguments and coefficients. This makes it easier to e.g. express the norm defined by a bilinear form as a functional. Example usage:

  # Equivalent to replace(a, {u: f, v: f})
  M = a(f, f)
  # Equivalent to replace(a, {f:1})
  c = a(coefficients={f:1})

• Add call operator syntax to Form to replace arguments and coefficients:

  a(f, g) == replace(a, {u: f, v: g})
  a(coefficients={f:1}) == replace(a, {f:1})

• Add @ operator to Form: form @ f == action(form, f) (python 3.5+ only)

• Reduce noise in Mesh str such that print(form) gets more short and readable

• Fix repeated split(function) for arbitrary nested elements

• EnrichedElement: Remove +/* warning

  In the distant past, A + B => MixedElement([A, B]). The change that A + B => EnrichedElement([A, B]) was made in d622c74 (22 March 2010). A warning was introduced in fcbc5ff (26 March 2010) that the meaning of + had changed, and that users wanting a MixedElement should use * instead. People have, presumably, been seeing this warning for 6 1/2 years by now, so it's probably safe to remove.

• Rework TensorProductElement implementation, replaces OuterProductElement

• Rework TensorProductCell implementation, replaces OuterProductCell

• Remove OuterProductVectorElement and OuterProductTensorElement

• Add FacetElement and InteriorElement

• Add Hellan-Herrmann-Johnson element

• Add support for double covariant and contravariant mappings in mixed elements

• Support discontinuous Taylor elements on all simplices

• Some more performance improvements

• Minor bugfixes

• Improve Python 3 support

• More permissive in integer types accepted some places

• Make ufl pass almost all flake8 tests

• Add bitbucket pipelines testing

• Improve documentation

2016.1.0 (2016-06-23)

• Add operator A^(i,j) := as_tensor(A, (i,j))
• Updates to old manual for publishing on fenics-ufl.readthedocs.org
• Bugfix for ufl files with utf-8 encoding
• Bugfix in conditional derivatives to avoid inf/nan values in generated code. This bugfix may break ffc if uflacs is not used, to get around that the old workaround in ufl can be enabled by setting ufl.algorithms.apply_derivatives.CONDITIONAL_WORKAROUND = True at the top of your program.
• Allow sum([expressions]) where expressions are nonscalar by defining expr+0==expr
• Allow form=0; form -= other;
• Deprecate .cell(), .domain(), .element() in favour of .ufl_cell(), .ufl_domain(), .ufl_element(), in multiple classes, to allow closer integration with dolfin.
• Remove deprecated properties cell.{d,x,n,volume,circumradius,facet_area}.
• Remove ancient form2ufl script
• Add new class Mesh to replace Domain
• Add new class FunctionSpace(mesh, element)
• Make FiniteElement classes take Cell, not Domain.
• Large reworking of symbolic geometry pipeline
• Implement symbolic Piola mappings

1.6.0 (2015-07-28)

• Change approach to attaching hash implementation to accomodate python 3
• Implement new non-recursive traversal based hash computation
• Allow derivative(M, ListTensor(), ...) just like list/tuple works
• Add traits is_in_reference_frame, is_restriction, is_evaluation, is_differential
• Add missing linear operators to ArgumentDependencyExtractor
• Add ufl_is_literal type trait
• Add ufl_is_terminal_modifier type trait and Expr.ufl_terminal_modifiers list
• Add new types ReferenceDiv and ReferenceCurl
• Outer product element support in degree estimation
• Add TraceElement, InteriorElement, FacetElement, BrokenElement
• Add OuterProductCell to valid Real elements
• Add _cache member to form for use by external frameworks
• Add Sobolev space HEin
• Add measures dI,dO,dC for interface, overlap, cutcell
• Remove Measure constants
• Remove cell2D and cell3D
• Implement reference_value in apply_restrictions
• Rename point integral to vertex integral and kept *dP syntax
• Replace lambda functions in ufl_type with named functions for nicer stack traces
• Minor bugfixes, removal of unused code and cleanups

1.5.0 (2015-01-12)

• Require Python 2.7
• Python 3 support
• Change to py.test
• Rewrite parts of expression representation core, providing significant optimizations in speed and memory use, as well as a more elaborate type metadata system for internal use
• Use expr.ufl_shape instead of ufl.shape()
• Use expr.ufl_indices instead of ufl.indices(), returns tuple of free index ids, not Index objects
• Use expr.ufl_index_dimensions instead of ufl.index_dimensions(), returns tuple of dimensions ordered corresponding to expr.ufl_indices, not a dict
• Rewrite core algorithms for expression traversal
• Add new core algorithms map_expr_dag(), map_integrand_dag(), similar to python map() but applying a callable MultiFunction recursively to each Expr node, without Python recursion
• Highly recommend rewriting algorithms based on Transformer using map_expr_dag and MultiFunction, avoiding Python recursion overhead
• Rewrite core algorithms apply_derivatives, apply_restrictions
• Form signature is now computed without applying derivatives first, introducing smaller overhead on jit cache hits
• Use form.signature() to compute form signature
• Use form.arguments() instead of extract_arguments(form)
• Use form.coefficients() instead of extract_coefficients(form)
• Small improvement to str and latex output of expressions
• Allow diff(expr, coefficient) without wrapping coefficient in variable
• Add keywords to measures: dx(..., degree=3, rule="canonical")
• Introduce notation from the Periodic Table of the Finite Elements
• Introduce notation for FEEC families of elements: P-, P, Q-, S
• Experimental support for high-order geometric domains
• Algorithms for symbolic rewriting of geometric quantities (used by uflacs)
• Remove the Constant classes, using Coefficient with a Real element instead
• Add types for MinValue and MaxValue
• Disable automatic rewriting a+a->2a, aa->a**2, a/a->1, these are costly and the compiler should handle them instead
• Fix signature stability w.r.t. metadata dicts
• Minor bugfixes, removal of unused code and cleanups

1.4.0 (2014-06-02)

• New integral type custom_integral (*dc)
• Add analysis of which coefficients each integral actually uses to optimize assembly
• Improved svg rendering of cells and sobolevspaces in ipython notebook
• Add sobolev spaces, use notation "element in HCurl" (HCurl, HDiv, H1, H2, L2)
• Improved error checking of facet geometry in non-facet integrals
• Improved restriction handling, restricting continuous coefficients and constants is now optional
• Introduce notation from the Periodic Table of the Finite Elements (draft)
• Remove alias "Q" for quadrature element, use "Quadrature"
• New derivative type ReferenceGrad
• New discontinuous RT element
• New geometry types Jacobian, JacobianInverse, JacobianDeterminant
• New geometry types FacetJacobian, FacetJacobianInverse, FacetJacobianDeterminant
• New geometry types CellFacetJacobian, CellFacetJacobianInverse, CellFacetJacobianDeterminant
• New geometry types FacetOrigin, CellOrigin
• New geometry types CellCoordinate, FacetCoordinate
• New geometry types CellNormal, CellOrientation, QuadratureWeight
• Argument (and TestFunction, TrialFunction) now use absolute numbering f.number() instead of relative f.count()
• New syntax: integrand*dx(domain)
• New syntax: integrand*dx(1, domain=domain)
• New syntax: integrand*dx(1, subdomain_data=domain_data)
• Using domain instead of cell in many places.
• Deprecated notation 'cell.n', 'cell.x' etc.
• Recommended new notation: FacetNormal(domain)
• Experimental: Argument (and TestFunction, TrialFunction) now can have a specified part index for representing block systems
• Experimental: Domains can now be created with a Coefficient providing coordinates: Domain(Coefficient(VectorElement("CG", domain, 2)))
• Experimental: New concept Domain: domain = Domain(triangle, geometric_dimension=3, label="MyDomain")
• Various general optimizations
• Various minor bugfixes
• Various docstring improvements

1.3.0 (2014-01-07)

• Add cell_avg and facet_avg operators, can be applied to a Coefficient or Argument or restrictions thereof
• Fix bug in cofactor: now it is transposed the correct way.
• Add cell.min_facet_edge_length
• Add cell.max_facet_edge_length
• Simplify 0^f -> 0 if f is a non-negative scalar value
• Add atan2 function
• Allow form+0 -> form

1.2.0 (2013-03-24)

• NB! Using shapes such as (1,) and (1,1) instead of () for 1D tensor quantities I, x, grad(f)
• Add cell.facet_diameter
• Add new concept Domain
• Add new concept Region, which is the union of numbered subdomains
• Add integration over regions (which may be overlapping by sharing subdomains)
• Add integration over everywhere
• Add functions cosh, sinh, tanh, Max, Min
• Generalize jump(v,n) for rank(v) > 2
• Fix some minor bugs

1.1.0 (2013-01-07)

• Add support for pickling of expressions (thanks to Graham Markall)
• Add shorthand notation A**2 == inner(A, A), special cased for power 2.
• Add support for measure sum notation f*(dx(0) + dx(3)) == fdx(0) + fdx(3)
• Supporting code for bugfix in PyDOLFIN when comparing test/trial functions
• Remove support for tuple form notation as this was ambiguous
• Bugfix in quadrature degree estimation, never returning <0 now
• Remove use of cmp to accomodate removal from python 3

1.1-alpha-prerelease (2012-11-18)

(Not released, snapshot archived with submission of UFL journal paper)

• Support adding 0 to forms, allowing sum([a])
• Major memory savings and optimizations.
• Some bugfixes.
• Add perp operator.
• Support nested tuple syntax like MixedElement((U,V),W)
• Allow outer(a, b, c, ...) by recursive application from left.
• Add simplification f/f -> 1
• Add operators <,>,<=,>= in place of lt,gt,le,ge

1.0.0 (2011-12-07)

• No changes since rc1.

1.0-rc1 (2011-11-22)

• Added tests covering snippets from UFL chapter in FEniCS book
• Added more unit tests
• Added operators diag and diag_vector
• Added geometric quantities cell.surface_area and cell.facet_area
• Fixed rtruediv bug
• Fixed bug with derivatives of elements of type Real with unspecified cell

1.0-beta3 (2011-10-26)

• Added nabla_grad and nabla_div operators
• Added error function erf(x)
• Added bessel functions of first and second kind, normal and modified, bessel_J(nu, x), bessel_Y(nu, x), bessel_I(nu, x), bessel_K(nu, x)
• Extended derivative() to allow indexed coefficient(s) as differentiation variable
• Made *Constant use the Real space instead of DG0
• Bugfix in adjoint where test and trial functions were in different spaces
• Bugfix in replace where the argument to a grad was replaced with 0
• Bugfix in reconstruction of tensor elements
• Some other minor bugfixes

1.0-beta2 (2011-08-11)

• Support c*form where c depends on a coefficient in a Real space

1.0-beta (2011-07-08)

• Add script ufl-version
• Added syntax for associating an arbitrary domain data object with a measure: dss = ds[boundaries]; M = fdss(1) + gdss(2)
• Added new operators elem_mult, elem_div, elem_pow and elem_op for elementwise application of scalar operators to tensors of equal shape
• Added condition operators And(lhs,rhs) and Or(lhs,rhs) and Not(cond)
• Fixed support for symmetries in subelements of a mixed element
• Add support for specifying derivatives of coefficients to derivative()

0.9.1 (2011-05-16)

• Remove set_foo functions in finite element classes
• Change license from GPL v3 or later to LGPL v3 or later
• Change behavior of preprocess(), form.compute_form_data(), form_data.preprocessed_form
• Allowing grad, div, inner, dot, det, inverse on scalars
• Simplify Identity(1) -> IntValue(1) automatically
• Added Levi-Cevita symbol: e = PermutationSymbol(3); e[i,j,k]
• Fix bug with future division behaviour (ufl does not support floor division)
• Add subdomain member variables to form class
• Allow action on forms of arbitrary rank

0.9.0 (2011-02-23)

• Allow jump(Sigma, n) for matrix-valued expression Sigma
• Bug fix in scalar curl operator
• Bug fix in deviatoric operator

0.5.4 (2010-09-01)

• Bug fixes in PartExtracter
• Do not import x for coordinate
• Add Circumradius to Cell (Cell.circumradius)
• Add CellVolume to Cell (Cell.volume)

0.5.3 (2010-07-01)

• Rename ElementRestriction --> RestrictedElement
• Experimental import of x from tetrahedron
• Make lhs/rhs work for resrictions
• Redefine operator + for FiniteElements and replace + by *
• Rename ElementUnion -> EnrichedElement
• Add support for tan() and inverse trigonometric functions

0.5.2 (2010-02-15)

• Attach form data to preprocessed form, accessible by form.form_data()

0.5.1 (2010-02-03)

• Fix bug in propagate_restriction

0.5.0 (2010-02-01)

• Several interface changes in FormData class
• Introduce call preprocess(form) to be called at beginning of compilation
• Rename BasisFunction --> Argument
• Rename Function --> Coefficient

0.4.1 (2009-12-04)

• Redefine grad().T --> grad()
• New meaning of estimate_max_polynomial_degree
• New function estimate_total_polynomial_degree
• Allow degree = None and cell = None for elements

0.4.0 (2009-09-23)

• Extensions for ElementRestriction (restrict FiniteElement to Cell)
• Bug fix for lhs/rhs with list tensor types
• Add new log function set_prefix
• Add new log function log(level, message)
• Added macro cell integral *dE
• Added mechanism to add additional integral types
• Added LiftingOperator and LiftingFunction
• Added ElementRestriction

0.3.0 (2009-05-28)

• Some critical bugfixes, in particular in differentiation.
• Added form operators "system" and "sensitivity_rhs".
• diff can take form as argument, applies to all integrands.
• Rudimentary precedence handling for better use of parentheses in str(expression).
• Added script ufl2py, mainly for debugging purposes.
• Crude implementation of estimate_max_polynomial_degree for quadrature degree estimation.
• Improved manual.

0.2.0 (2009-04-07)

• Initial release of UFL.

0.1.0 (unreleased)

• Unreleased development versions of UFL.