## An Interesting 2-5 Progression

When playing a 2-5 progression, here’s a way to add a few interesting chords in between.

The principle is that you walk up from the 2 chord to the 5 chord.

i.e. 2 3 4 ♭5 5.

Alternatively, to make it easier, you can take out the 4 and walk up as follows:

2 3 ♭5 5

An example of this is:

2minor7 1maj/3 4maj7 ♭5(with a quartal chord of its flattened 7th note) 513

The fourth chord there deserves more explanation.

Let’s assume we are in the key of D, what does a ♭5 (with a quartal chord of its flattened 7th note) mean?

Well, first ♭5 tone of D♭major will be G.

The 7th note of G major is F

Then we play a quartal chord of F (F B E) on the right hand over G on the left hand.

In the key of D♭ the walk-up will be as follows

Chord LH RH
E♭minor7 E B D G
D♭major / F F A D F
G♭major7 G F B D
G (with a quartal chord of its flattened 7th note) G F B E
A♭13 A G B D F

Below is a recording of the first variant:

And of the second variant.

I use the second variant in Thank You Lord posted earlier. See if you can spot it!

Enjoy.

## How to Document Django Applications with Sphinx

In this post I go over how to automatically document Django applications. By this I refer to a way to run a tool that automatically reads your projects and docstrings and generates beautiful documentation. Sphinx is an excellent tool for the job. Sphinx makes it easy to create beautiful intelligent documentation for projects. It uses reStructuredText as its markup language. Here’s how to go about it.

First install Sphinx using the command:

pip install sphinx


Initialise Sphinx

sphinx-quickstart


You will be asked several questions which will be used to generate a configuration file, a few folders and possibly a Makefile. You will want to make sure you enable autodoc to allow generating documentation from docstrings as well as the generation of Makefile so that you can run the make command in the future to update documentation. Below is an example of the what the screen looks like for these

Welcome to the Sphinx 1.6.1 quickstart utility.

Please enter values for the following settings (just press Enter to
accept a default value, if one is given in brackets).

Enter the root path for documentation.
> Root path for the documentation [.]: ./docs

You have two options for placing the build directory for Sphinx output.
Either, you use a directory "_build" within the root path, or you separate
"source" and "build" directories within the root path.
> Separate source and build directories (y/n) [n]: n

Inside the root directory, two more directories will be created; "_templates"
for custom HTML templates and "_static" for custom stylesheets and other static
files. You can enter another prefix (such as ".") to replace the underscore.
> Name prefix for templates and static dir [_]:

The project name will occur in several places in the built documentation.
> Project name: Your Project Name
> Author name(s): Some Author Name

Sphinx has the notion of a "version" and a "release" for the
software. Each version can have multiple releases. For example, for
Python the version is something like 2.5 or 3.0, while the release is
something like 2.5.1 or 3.0a1.  If you don't need this dual structure,
just set both to the same value.
> Project version []: 0.1
> Project release [0.1]:

If the documents are to be written in a language other than English,
you can select a language here by its language code. Sphinx will then
translate text that it generates into that language.

For a list of supported codes, see
http://sphinx-doc.org/config.html#confval-language.
> Project language [en]:

The file name suffix for source files. Commonly, this is either ".txt"
or ".rst".  Only files with this suffix are considered documents.
> Source file suffix [.rst]:

One document is special in that it is considered the top node of the
"contents tree", that is, it is the root of the hierarchical structure
of the documents. Normally, this is "index", but if your "index"
document is a custom template, you can also set this to another filename.
> Name of your master document (without suffix) [index]:

Sphinx can also add configuration for epub output:
> Do you want to use the epub builder (y/n) [n]:

Please indicate if you want to use one of the following Sphinx extensions:
> autodoc: automatically insert docstrings from modules (y/n) [n]: y
> doctest: automatically test code snippets in doctest blocks (y/n) [n]: y
> intersphinx: link between Sphinx documentation of different projects (y/n) [n]: y
> todo: write "todo" entries that can be shown or hidden on build (y/n) [n]: y
> coverage: checks for documentation coverage (y/n) [n]: y
> imgmath: include math, rendered as PNG or SVG images (y/n) [n]: y
> mathjax: include math, rendered in the browser by MathJax (y/n) [n]:
> ifconfig: conditional inclusion of content based on config values (y/n) [n]:
> viewcode: include links to the source code of documented Python objects (y/n) [n]:
> githubpages: create .nojekyll file to publish the document on GitHub pages (y/n) [n]:

A Makefile and a Windows command file can be generated for you so that you
only have to run e.g. make html' instead of invoking sphinx-build
directly.
> Create Makefile? (y/n) [y]:
> Create Windows command file? (y/n) [y]: n

Creating file ./docs/conf.py.
Creating file ./docs/index.rst.
Creating file ./docs/Makefile.

Finished: An initial directory structure has been created.

You should now populate your master file ./docs/index.rst and create other documentation
source files. Use the Makefile to build the docs, like so:
make builder
where "builder" is one of the supported builders, e.g. html, latex or linkcheck.


Upon completion, a docs file should appear in your project.

## Generate HTML Documentation

You can then generate documentation in HTML format by changing to the docs folder and running the following command:

make html


You should see something like:

Running Sphinx v1.6.1
making output directory...
intersphinx inventory has moved: https://docs.python.org/objects.inv -> https://docs.python.org/2/objects.inv
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 1 source files that are out of date
updating environment: 1 added, 0 changed, 0 removed
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [100%] index
generating indices... genindex
copying static files... done
copying extra files... done
dumping search index in English (code: en) ... done
dumping object inventory... done
build succeeded.

Build finished. The HTML pages are in _build/html.


## Document Project Modules

Now we will tell Sphinx to document the modules of one of our applications.

Open docs/conf.py

After the first block of comments, add the following code so that Sphinx can read docstrings from project files:

import os
import sys
import django
sys.path.insert(0, os.path.abspath('..'))
os.environ['DJANGO_SETTINGS_MODULE'] = 'yourprojectname.settings'
django.setup()


Next, create a modules folder within docs. We will use these to hold our documentation. E.g. To document models, create a file at modules/models.rst.

Edit models.rst and add the following content:

Models
======
.. automodule:: yourappname.models
:members:


Save and close the file.

Next, make this link available in the documentation index by editing docs/index.rst.

Find the section starting with .. toctree:: and add a line modules/models under it so that it looks like this:

.. toctree::
:maxdepth: 2
:caption: Contents:

modules/models



Save and close the file.

Now is the time to regenerate the documentation.

Run the following command from inside the docs folder.

make html


You can access the documentation by opening docs/_build/html/index.html in a browser. You should see ‘Models’ under ‘Content’.

That’s it!

If you want to be able to access your documentation from the Django application itself, e.g. using a link like /docs/, you can do this using the awesome django-docs package.

Enjoy.

Reference

## How to force git push after resetting a branch to a previous commit

Hi folks,

In this post I’ll share a really small but handy tip I discovered while using Git.

Let’s say you make some commits on your local repository which you later find undesirable. You can of course use git reset –hard to put the repository in previous state that doesn’t have those commits.

Let’s assume that later (perhaps after adding a few fresh commits) you try to push this to the remote repository, git will refuse by default because the remote repository has more commits.

To force git to accept the push you need to add the -f flag.

git push -f
`

Note: you should only force a push if you are the only one with access to the repository or you are sure that other users haven’t cloned the existing state of the remote repository, otherwise forcing a push could lead to problems of diverging history for other users.