Brief

As of July 2020, the casa6 core component casatools is only available as Py36 wheels for macOS/Linux. If Python 3.6 is the default interpreter, you can just use pip-3.6 with this requirements file for installation.

$  pip install --user --upgrade -r requirement_casa6pip36.txt

However, if you are using Python >=3.7 for workflow/development, the standard pip procedure won’t work.

casa6-install provides a command-line program as a temporary workaround on the current installation issue, before the official support of the latest Python and OS from NRAO. It can help install casatools along with other casa6 modules in one step (tested on macOS10.15 and Ubuntu20.04), let you have a working copy of casa6 modules with Python >=3.7.

Usage

You have two options to use the casa6-install:

Option 1: Install as a Python Package and Run the CLI tool

Install the tool from PyPi or the GitHub repository, e.g.,

$ pip install --user casa6-install

With the “–user” option, you must add the user-level bin directory (e.g., ~/Library/Python/3.8/bin) to your PATH environment variable. After this, try:

$ casa6_install --user --upgrade

A full summary of the casa6_install command options is available:

$ casa6_install --help

Option 2: Use the Python Module Directly

You may download the python module file casa6_install/casa6_install.py and use it directly:

$ python casa6_install.py

Note

  • The program is not affiliated with NRAO and the official CASA6 development. It only serves for code developmental purposes, e.g., building/testing your own Python program/pipeline using casa6 modules. The tool modifies the official Py36 .whl file to make it “compatible” with Py37/38 (see Background below). It doesn’t build a binary from scratch.

  • Although the hacking approach in casa-install will get working casa6 modules on macOS>=10.14 with Python>=3.7, it doesn’t guarantee that the installed package will work properly on Linux. This is due to various library dependency (e.g. lack of libgfortran3) and many potential differences between the building platform and your local OS distribution. Specifically for Ubuntu20.04, please check out this Dockerfile on how to work around the dependency issue (involving the manual installation of libtinfo5, libquadmath0, libgfortran3). For this moment, I found no issue at least when using casatools and casatasks for development purposes.

  • You may need to remove previous installations before upgrading modules due to version inter-dependency:

$ pip uninstall --yes casadata casatools casatasks casaviewer casashell

Smoke Test

In [1]: import casatasks, casatools

In [2]: print('casatools ver:',casatools.version_string())
casatools ver: 6.2.0.3

In [3]: print('casatasks ver:',casatasks.version_string())
casatasks ver: 6.2.0.3

Background

The program essentially performs the following procedures:

First, casa6-install downloads the latest Py36 .whl for Linux or macOS to a working directory (default to /tmp) using pip download. The equivalent command will be,

$ pip download --python-version 36 --abi cp36m --no-deps \
    --extra-index-url https://casa-pip.nrao.edu/repository/pypi-group/simple \
    casatools

Then it will unpack .whl, perform necessary modifications to files inside, and repack them with the correct ABI matching to your Python versions.

Finally, it will spawn a subprocess and install the modified .whl, along with other casa6 packages (i.e., casatasks, casashell, casaviewer, casaplotms, casampi) which are not platform-specific. The equivalent console command will be something like:

$ pip install --user --upgrade \
    --extra-index-url https://casa-pip.nrao.edu:443/repository/pypi-group/simple \
    casadata
$ pip install --user --upgrade \
    casatools-6.1.0.107-cp36-cp36m-macosx_10_15_x86_64.whl ## assume you're working on macOS10.15
$ pip install --user --upgrade \
    --extra-index-url https://casa-pip.nrao.edu:443/repository/pypi-group/simple \
    casatasks casashell casaplotms casaviewer

  • The locations of the casaviewer and plotms are a little bit obscure and will sit in the site-packages directory, e.g. (if pip --user):

    ~/Library/Python/3.8/lib/python/site-packages/casaviewer/__bin__/casaviewer.app
~/Library/Python/3.8/lib/python/site-packages/casaplotms/__bin__/casaplotms.app

  • You may need to remove previous installations before upgrading modules due to version inter-dependency,

$ pip uninstall --yes casadata casatools casatasks casaviewer casashell