# Change log

The list below gives a human-readable overview of the changes from one version to the next. For details of precisely what is changed at the code level, consult the github repository. Odd patch levels correspond to versions in development, even numbered ones are released in packaged form.

### github master (2.4.1)

- Add missing trig functions for display and passthrough to sympy (Oscar).

### 2.4.0 (released 25-Aug-2022)

- Version to accompany the publication of the paper about the meld algorithm.
- Several fixes to
`meld`(Dominic). - Make typesetting run in a separate thread to prevent the UI from feeling sluggish.
- Some changes in the behaviour of list addition/multiplication, to match Mathematica's behaviour.
- New
`nevaluate`algorithm for fast numerical evaluation of expressions (work-in-progress). - Fix for Python 3.10.x.
- Fix for automatic cleanup of
`Diagonal`objects. - Fix crash with tab-completion.
- Make '+' operator add lists component-wise, and introduce the
tie operator '~' and
`join`function to join lists. - Fix printing of objects with
`LaTeXForm`which are wrapped in another LaTeX operator.

### 2.3.8 (released 21-Nov-2021)

- Option to display negative powers as fractions (Dominic).
- New algorithm
`slot_asym`to (anti-)symmetrise objects in indices by giving index positions instead of names. - New functionality to implement algorithms in Python (Dominic).
- Faster re-implementation of
`get_component`using new C++ function modules (Dominic). - New
`cdb.numeric.evaluate`and`cdb.numeric.integrate`modules to evaluate expressions numerically or integrate differential equations numerically (Dominic). - Updates to
`cdb.utils.indices`and`cdb.core.manip`. - Add warnings functionality to the kernel (Dominic).
- Add infrastructure to let algorithms display progress information while running (Dominic).
- Add cell cursor position to status bar (Dominic).
- Fix bug in
`expand_delta`when the delta occurs at top-level in an expression. - Many
`meld`fixes and improvements (Dominic). - Fix handling of auto-declare names (names with a '#' character).
- Keep LaTeX log/aux files on error to aid debugging.
- Fix LaTeX code to avoid some global variable name clashes.
- Fix for compilation on Apple silicon.

### 2.3.6 (released 30-Dec-2020)

- Once further change to the installation path of
the
`cadabra2.so`module, so that it conforms with standard conventions, in particular Debian packaging rules. On Debian-based systems, you should now be able to use the Cadabra python module without path settings, and the Jupyter kernel will work nicely with the Jupyter package in Debian. - Fix display of lists containing
`Ex`objects. - Fix import of Jupyter notebooks.
- Fix bug related to automatic dummy index relabelling.
- Fix tab-completion.
- Fix build issues on recent versions of HomeBrew/macOS.

### 2.3.4 (released 16-Nov-2020)

- Fix a display bug which turned all products into tensor products.
- Enable attaching properties queried with
`Property.get`to new symbols. - Fix bug pulling with
`@(...)`operator. - Add option
`redundant`to`eliminate_metric`to only eliminate metrics which have two dummy indices (David). - Added option to export notebooks to Jupyter, and a command-line utility to do the same.

### 2.3.2 (released 31-Oct-2020)

- Fixed bug in pattern matching logic used
in
`integrate_by_parts`; see this Q&A post. - Fixed bug which would prevent assignment to node multiplier from Python.
- Tab-completion on command line and in the notebook.
- Install the
`cadabra2`python module in a standard location (Atri). You may still need to set`PYTHONPATH`if you are on Debian/Ubuntu. - Fixes for the Mathematica scalar backend.
- Make
`expand_delta`much faster when the Kronecker delta is contracted with objects which have anti-symmetry. - Make meld work correctly with non/anti-commuting objects (Dominic).
- Make numbered indices like
`a1`display with a subscript automatically`a`._{1} - Provide
`pickle`functionality for expressions (Dominic). - Fixes for compatibility with newer
`SymPy`versions. - Added a 'find' function in the notebook, to search input cells.
- New Jupyter kernel (enabled by default) which does not require Xeus; you can now get access to Cadabra on Jupyter on all supported systems, not just Conda (Fergus).
- Various improvements and fixed for handling and display of Young tableaux.
- Added
`ExNode::ex()`to obtain an`Ex`object from an`ExNode`iterator.

### 2.3.0 (released 10-Jun-2020)

- Fix bug which would collect powers of objects with indices and then report an error.
- Functionality to read Cadabra Cloud notebooks into the desktop Cadabra.
- Use a better hash function for expression trees (avoiding a bug
in
`factor_in`). - Expose index symmetries through traces, so that canonicalise and
related algorithms work correctly. Introduced a new
property
`TableauInherit`. - More flexible
`LaTeXForm`property, to enable more flexible object display in the notebook. - Various fixes for behaviour of
`unwrap`with anti- or non-commuting arguments. - New
`meld`algorithm for canonicalisation (Dominic).

### 2.2.8 (released 10-Dec-2019)

- More versatile handling of
`Trace`, including sorting using cyclic symmetry (Connor). - Fixes for
`combine`(Connor). - Save command-line history (Connor).
- Make imported notebooks use the default
`post_process`function. - Make
`unwrap`move scalars out of exterior (wedge) products, see this Q&A post. - Fix bug with indices with accents (github/166).
- Added a
`cadabra2latex`command to convert notebooks to LaTeX. - Fixed issue building with latest Homebrew on macOS.
- Fixed Windows build issues and add python path settings at runtime.
- Fixed bug with multipliers not reducing to canonical form.

### 2.2.7 (released 25-Jun-2019)

- Added
`cdb.utils.develop`and`cdb.relativity.abstract`. - Added authentication token to all client-server communication.
- Various extensions to the
`Trace`property. - Make property info available from Python (Dominic).
- Fixed integration by parts with index-less derivatives.
- Added
`eliminate_vielbein`. - Fixed display of lists of sympy expressions.
- Fixed (finally) UTF8 input for non-English symbols.

### 2.2.6 (released 16-Apr-2019)

- Experimental notebook diff viewer (Dominic).
- Warn when about to overwrite an existing notebook.
- Improvements for HiDPI screens especially on macOS.
- Fix crash in
`sym/asym`. - Fix undo/redo crash in notebook when deleting cells.
- Improvements to the
`cdb.core.manip`package (Dominic). - Fix in
`young_project_tensor`. - Fix pattern matching for anti-commuting factors.
- Added
`explicit_indices`to convert expressions with implicit indices to their explicit form. - Add option to build a Jupyter kernel.
- Fix bug in
`split_index`(acted on wrong parts of expressions). - Fix bug with substitute not checking constraints for single-factor patterns.
- Add
`partial`option to substitute to require that products or sums match all terms, not just a partial sum or partial product.

### 2.2.5 (released 05-Feb-2019)

- Fix issues with
`Derivative`objects going through Sympy. - Fix a bug with LaTeX export.
- Enable build against system-supplied JSONCPP.

### 2.2.4 (released 19-Dec-2018)

- Fix to make simplify see the Mathematica backend again.
- Fix export of notebooks to LaTeX.
- Fix display of LaTeXForm property declaration.
- Added Python methods to traverse the expression tree.
- Fix for power simplification bug (github/85)
- Fix to make command line version accept primes in expression input (github/85)
- Fix for indices being treated as dependencies (github/89)
- Various improvements
for
`replace_match`. - Optional syntax highlighting in input cells (Dominic).
- Added
`lower_free_indices`and`raise_free_indices`. - Various small fixes for terminal output.
- 'Evaluate to cursor' in the notebook now works.
- Substituting now properly distinguishes between indices and non-indices, see this Q&A post.
- Added
`einsteinify`. - Do not attempt to write out sums over index values
in
`evaluate`if the range is not known, simply keep them unevaluated (instead of throwing an error). - Introducing
`zoom`/unzoom as a more friendly and powerful alternative to`take_match`/`replace_match`. - Fix for display of LaTeXForm'ed objects in sub/superscripts.
- New build system using Ninja on Windows (Dominic).
- Fix bug in unwrap with derivatives with respect to explicit coordinates (see Unwrap applied...).
- It is now possible to import notebooks into other notebooks (Dominic).
- New system package for expression manipulation (cdb.core.manip).
- Export to LaTeX fixed, and now also exports figures.
- Added a debugging console to the notebook interface (Dominic).

### 2.2.0 "Easter Bunny" (released 29-Mar-2018)

- Now builds on Windows (Dominic).
- Experimental support for modifying the expression tree directly from Python (see e.g. Fourier transforms).
- Now building on OpenBSD.
- Fix for integration by parts (github/71)
- Fix for incorrect conversion to sympy expressions.
- Optionally build with support for (experimental!) Mathematica scalar
backend; see
`map_mma`. - Many bugfixes for expression display and sympy conversion.
- Now using pybind instead of boost.python, in preparation for Windows port, and to enable building against Anaconda.
- Copy/paste of output cells added.
- New
`simplify`command, which simplifies the scalar parts of expressions, and can be switched to use either Sympy or Mathematica. - Fix to treat derivatives with respect to explicit coordinates as
scalars in
`evaluate`; see this Q&A post. - Fix for failure to flag errors for WeightInherit property.
- Fixed: vary on single-term expressions (github/57)
- Fixed: evaluate with dense factors and no 'values' property on indices (github/68)

### 2.1.7 (released 20-Nov-2017)

- Various bugfixes.

### 2.1.6 (released 1-Nov-2017)

- Make the wedge product distributable.
- Fix printing of wedge products with sums in factors.
- Fixed printing of index brackets.
- Add RPATH to binaries to avoid having to run
`ldconfig`after installation. - Fix for the theming to avoid invisible text with dark themes.

### 2.1.5 (released 6-Aug-2017)

- Introduced
`map_sympy`which can be used to apply Sympy functions to Cadabra expressions, acting in-place. - Fixed: expressions with powers often lack brackets.

### 2.1.4 (released 14-Apr-2017)

- Enable packages to be written using Cadabra notation, instead of only pure Python (still experimental).
- Young tableaux
properties
`Tableau`and`FilledTableau`the related algorithm`lr_tensor`are available again. - Sorting Majorana spinors possible again using
`sort_spinors`. - Extended
`rename_dummies`with capability to rename indices to different set. - Make
`vary`work on powers of expressions with dummy indices. - Substitution of sub-sums now available
(e.g. substitute of
`A+B=C`in`ex:=A+B+C+D`). - Improved LaTeX export to make printed notebooks look much better.
- Many improvements to the component engine, in particular for handling of derivatives and fractions involving tensors.
- Better line spacing for line-wrapped equations.
- Smarter scroll-to-cell behaviour of the notebook.
- Canonicalising expressions with component values for indices now works again.
- The
`unwrap`algorithm can now be guided about what to unwrap, and also knows about spinors and Dirac bars. - Experimental support to use Cadabra directly from C++ code, as a
library (see
the
`c++lib`directory). - Fixes for using a custom
`post_process`defined as a function nested inside another. - Rudimentary timing logic, try
`server.totals();` - Fixed: pasting text in the notebook sometimes double-pastes.
- Fixed:
`split_index`does not work properly on left- and right-hand side of equations. - Fixed:
`sort_product`does not always sort expressions. - Fixed:
`eliminate_metric`only acts at top level of an expression, should have`deep=True`by default. - Fixed: a bug which would lead to a segfault when using
`deep=True`.

### 2.1.2 (released 4-Jan-2017)

- Bug fix: Crash on opening of a notebook on Ubuntu 16.04 and possibly others, related to minor differences in gtk versions.
- Bug fix: Installation paths of Debian/Ubuntu/Mint binary
packages changed from
`/usr/local`to`/usr`.

### 2.1.1 (released 3-Jan-2017)

- Bug fix: Compilation error on gtk versions lower than 3.10.0.

### 2.1.0 (released 3-Jan-2017)

- First properly versioned release after a series of 2.0.x releases which were meant for testing.