Merge pygae/master until commit 09ecbd1 and fixes pga and small stuffs

Author: meuns

.lgtm.yml

@@ -0,0 +1,9 @@
+# ignore the example files, we don't need quality there, and they skew our
+# stats and drown out real issues
+path_classifiers:
+  examples:
+    - examples
+  test:
+    - test
+  docs:
+    - doc

README.md

@@ -12,7 +12,7 @@ Development Status
 
 ![PyPI - Status](https://img.shields.io/pypi/status/galgebra.svg) ![GitHub contributors](https://img.shields.io/github/contributors/pygae/galgebra.svg) [![Codacy Badge](https://api.codacy.com/project/badge/Grade/fe7642c639a54d909a36c75db6c2fa49)](https://app.codacy.com/app/utensilcandel/galgebra?utm_source=github.com&utm_medium=referral&utm_content=pygae/galgebra&utm_campaign=Badge_Grade_Settings) [![Codecov](https://img.shields.io/codecov/c/github/pygae/galgebra.svg)](https://codecov.io/gh/pygae/galgebra)
 
-[brombo/galgebra](https://github.com/brombo/galgebra) was originally written by Alan Bromborsky, but is no longer actively maintained.
+[brombo/galgebra][] was originally written by Alan Bromborsky, but was no longer actively maintained, and as of 2019-11-25 no longer exists.
 
 [pygae/galgebra](https://github.com/pygae/galgebra) is a community fork, maintained by [Pythonic Geometric Algebra Enthusiasts](https://github.com/pygae).
 
@@ -100,7 +100,7 @@ You may also check out more examples [here](https://github.com/pygae/galgebra/bl
 
 For detailed documentation, please visit https://galgebra.readthedocs.io/ .
 
-**NOTE:** If you are coming from [sympy.galgebra](https://docs.sympy.org/0.7.6.1/modules/galgebra/) or [brombo/galgebra](https://github.com/brombo/galgebra), please check out section [Migration Guide](#migration-guide) below.
+**NOTE:** If you are coming from [sympy.galgebra](https://docs.sympy.org/0.7.6.1/modules/galgebra/) or [brombo/galgebra][], please check out section [Migration Guide](#migration-guide) below.
 
 Installing GAlgebra
 ---------------------
@@ -176,7 +176,7 @@ Simply remove the `sympy.` prefix before `galgebra` then you are good to go:
 from galgebra.ga import *
 ```
 
-### Migrating from [brombo/galgebra](https://github.com/brombo/galgebra)
+### Migrating from [brombo/galgebra][]
 
 The `setgapth.py` way to install is now deprecated by `pip install galgebra` and all modules in GAlgebra should be imported from `galgebra`, for example:
 
@@ -194,3 +194,5 @@ Note that in the [doc/books](https://github.com/pygae/galgebra/blob/master/doc/b
 - `BookGA.pdf` which is a collection of notes on Geometric Algebra and Calculus based of "Geometric Algebra for Physicists" by Doran and Lasenby and on some papers by Lasenby and Hestenes.
 - `galgebra.pdf` which is the original main doc of GAlgebra in PDF format, while the math part is still valid, the part describing the installation and usage of GAlgebra is outdated, please read with cautious or visit https://galgebra.readthedocs.io/ instead.
 - `Macdonald` which constains bundled supplementary materials for [Linear and Geometric Algebra](http://www.faculty.luther.edu/~macdonal/laga/index.html) and [Vector and Geometric Calculus](http://www.faculty.luther.edu/~macdonal/vagc/index.html) by Alan Macdonald, see [here](https://github.com/pygae/galgebra/blob/master/doc/books/Macdonald/) and [here](https://github.com/pygae/galgebra/blob/master/examples/Macdonald/) for more information.
+
+[brombo/galgebra]: https://web.archive.org/web/20180611145113/https://github.com/brombo/galgebra

__init__.py

@@ -2,6 +2,33 @@
 Changelog
 =========
 
+- :feature:`78` :meth:`~galgebra.ga.Ga.grads` now raises a better error when it fails, and is faster.
+- :support:`72` Other internal cleanup
+- :feature:`66` (also :issue:`67`, :issue:`71`) Remove unused code in the public API:
+
+  * ``Ga.mul_table``, ``Ga.wedge_table``, ``Ga.dot_table``, ``Ga.left_contract_table``,
+    and ``Ga.right_contract_table``, all of which were the empty list, ``[]``.
+  * ``galgebra.mv.modules``, a string which served no purpose
+  * ``__add_ab__``, ``__sub_ab__``, ``__mul_ab__``, and ``__div_ab__``, none of are real magic method names.
+    No code should be calling these directly anyway.
+
+- :feature:`66` The :attr:`~galgebra.ga.Ga.mul_table_dict` table, and the equivalent tables for the other products, are now computed lazily when indexed. These are now all documented too.
+- :bug:`61` Make contraction and Hestenes dot products thread-safe.
+  Previously these relied on the :attr:`~galgebra.ga.Ga.dot_mode` setting not being changed mid-operation.
+  The :meth:`~galgebra.ga.Ga.dot` method still respects this setting, but is no longer used internally.
+- :bug:`60` Make :meth:`~galgebra.mv.Mv.blade_rep` and :meth:`~galgebra.mv.Mv.base_rep` not mutate the object they are called on.
+  Any code relying on this behavior will need to change from ``x.base_rep()`` to ``x = x.base_rep()``.
+- :support:`59` (also :issue:`65`) Make internal helper functions private.
+- :support:`57` (also :issue:`58`) Clean up the ``Mv(name, 'category')`` constructors to produce better error messages.
+- :support:`55` Rename ``*kargs`` to ``*args`` internally, to match convention.
+  This has no effect on callers, but makes the docs and source easier to read.
+- :feature:`50` (also :issue:`51`, :issue:`56`) Improve documentation formatting:
+
+    * LaTeX and code samples are now appropriately formatted
+    * Attributes of classes now have permalinks
+
+- :support:`46` (also :issue:`69`) Remove unnecessary executable bit from importable python files, and the corresponding no-op code that would be run.
+
 - :release:`0.4.4 <2019.09.30>`
 - :feature:`17` Fix examples under both Python 2 & 3