Add changelog, update version, update docs

CHANGELOG.rst

@@ -0,0 +1,38 @@
+`Unreleased <https://github.com/pace-neutrons/Euphonic/compare/v0.2.0...HEAD>`_
+----------
+
+`v0.2.0 <https://github.com/pace-neutrons/Euphonic/compare/v0.1-dev3...v0.2.0>`_
+------
+
+- There are several breaking changes:
+
+  - Changes to the object instantiation API. The former interface
+    ``InterpolationData(seedname)`` has been changed to
+    ``InterpolationData.from_castep(seedname)`,` in anticipation of more codes
+    being added which require more varied arguments.
+  - Changes to the Debye-Waller calculation API when calculating the structure
+    factor. The previous ``dw_arg`` kwarg accepted either a seedname or length
+    3 list describing a grid. The new kwarg is now ``dw_data`` and accepts a
+    ``PhononData`` or ``InterpolationData`` object with the frequencies
+    calculated on a grid. This is to make it clearer to the user exactly what
+    arguments are being used when calculating phonons on the grid.
+  - Changes to parallel functionality. The previous parallel implementation
+    based on Python's multiprocessing has been removed and replaced by a
+    C/OpenMP version. This has both better performance and is more robust. As
+    a result the ``n_procs`` kwarg to ``calculate_fine_phonons`` has been
+    replaced by ``use_c`` and ``n_threads`` kwargs.
+
+- Improvements:
+
+  - The parallel implementation based on Python's multiprocessing has been
+    removed and now uses C/OpenMP which both has better performance and is more
+    robust
+  - Documentation has been moved to readthedocs and is more detailed
+  - Clearer interface for calculating the Debye-Waller factor
+  - Better error handling (e.g. empty ``InterpolationData`` objects, Matplotlib
+    is not installed...)
+
+- Bug fixes:
+
+  - Fix gwidth for DOS not being converted to correct units
+  - Fix qwidth for S(Q,w) broadening being incorrectly calculated

doc/source/index.rst

@@ -50,8 +50,13 @@ Installing the C extension (optional)
 Euphonic has an optional C extension, which can lead to increased performance
 and enable use of multiple cores when interpolating phonons. By default
 Euphonic will attempt to install this extension, but will print a warning and
-fall back to the pure Python version
-if this fails.
+fall back to the pure Python version if this fails. To determine if the C
+extension is installing properly and investigate any problems, it is best to
+increase pip's verbosity:
+
+.. code-block:: bash
+
+    pip install -vvv euphonic
 
 **Windows**
 
@@ -65,20 +70,10 @@ the same pip commands as above.
 
 **Linux**
 
-The recommended compiler is ``gcc`` (currently tested with ``4.8.5``), first the
-environment variable ``CC`` must be set to the gcc compiler:
-
-.. code-block::  bash
+You should have a version of ``gcc`` on your path (currently tested with
+``4.8.5``). If ``gcc`` can be found the Euphonic extension will be automatically
+installed when using the same pip commands as above.
 
-    export CC=gcc
-
-Then the Euphonic extension will be automatically installed when using the same
-pip commands as above. If installing the C extension is failing, you can
-investigate by increasing pip's verbosity with the ``-vvv`` flag:
-
-.. code-block:: bash
-
-    pip install -vvv euphonic
 
 .. toctree::
    :hidden:

euphonic/__init__.py

@@ -1,7 +1,16 @@
-from pint import UnitRegistry
+__version__ = '0.2.0'
+
+try:
+    # Create ureg here so it is only created once. However, this __init__.py
+    # needs to be imported by setup.py to find __version__, so allow pint import
+    # to fail as in this case pint might not be installed yet
+    from pint import UnitRegistry
+
+    ureg = UnitRegistry()
+    # All values from CODATA 2014
+    ureg.define('rydberg = 13.605693009*eV = Ry')
+    ureg.define('bohr = 0.52917721067*angstrom = a_0')
+    ureg.define('electron_mass = 0.0005485799093*amu = e_mass')
+except ImportError:
+    pass
 
-ureg = UnitRegistry()
-# All values from CODATA 2014
-ureg.define('rydberg = 13.605693009*eV = Ry')
-ureg.define('bohr = 0.52917721067*angstrom = a_0')
-ureg.define('electron_mass = 0.0005485799093*amu = e_mass')

setup.py

@@ -1,4 +1,4 @@
-import os
+from euphonic import __version__
 
 try:
     from setuptools import setup, find_packages, Extension
@@ -8,6 +8,7 @@
 def run_setup(build_c=True):
 
     if build_c:
+        import os
         import numpy as np
         include_dirs = [np.get_include(), 'c']
         sources = ['c/_euphonic.c', 'c/dyn_mat.c', 'c/util.c', 'c/py_util.c',
@@ -48,7 +49,7 @@ def run_setup(build_c=True):
 
     setup(
         name='euphonic',
-        version='0.1dev3',
+        version=__version__,
         author='Rebecca Fair',
         author_email='[email protected]',
         description=(