2.1. Installing

The simplest, system-agnostic, way to install SciExp²-ExpDef is using the package from the official Python Package Index (PyPi [1]) using virtualenv and pip [2]. Using virtualenv will ensure you have a controlled local installation of a specific version for each of your projects, making sure your scripts always use the same SciExp²-ExpDef version to avoid any possible future version incompatibilities.

  1. Install virtualenv and pip.

  2. Create a python package “environment”:

    virtualenv --system-site-packages ~/my-expdef

You can create as many as you want; e.g., one for each different version of the SciExp²-ExpDef package that you want to test.

If you want to ignore the python packages installed on the system, you can instead run:

virtualenv ~/my-expdef

  1. Install SciExp²-ExpDef:

    . ~/my-expdef/bin/activate
pip install sciexp2-expdef

    Or to install a specific version (version 0.0.0 in the example):

    . ~/my-expdef/bin/activate
pip install "sciexp2-expdef==0.0.0"

2.2. Running

If you have installed SciExp²-ExpDef using pip, just remember to activate your environment before using it:

. ~/my-expdef/bin/activate
# programs and paths are now properly set up

Note

Many potentially long operations provide a feedback in the form of progress indicators; you can control whether they are shown through sciexp2.common.progress.level.

2.2.1. SciExp²-ExpDef and Make

In you use make to automate the execution of your scripts, here is a simple snippet you can add to your Makefile (the example uses version 0.0.0 of SciExp²-ExpDef):

all: deps/expdef
      # run our script using expdef
      ( . deps/expdef/bin/activate && /path/to/my/script.py )

# the ".done" file ensures a partial installation will not count as a success
deps/expdef: deps/expdef/.done
      $(RM) -R $@
      mkdir -p $(dir $@)
      virtualenv --system-site-packages $@
      ( . $@/bin/activate && pip install "sciexp2-expdef==0.0.0" )
      touch $<

2.2.2. Debugging aids

You can start your scripts with ipython --pdb /path/to/my/script.py to get into a debugging shell whenever an error occurs [3]. Sometimes it is also useful to start an IPython shell [4] somewhere deep in your code to interactively evaluate its current state:

from IPython import embed
embed()

Exiting the debugging shell will returning to normal execution.