Use StartExternalSession with Python (V12 Mac OS)?

Questions
1

Hi,
I am using the new 12.0 release of Mathematica.

I have Python 2.7 installed on my Mac and it is working fine (from shell). When I execute

FindExternalEvaluators[]

it correctly identifies my Python installation. However, when I execute

StartExternalSession[“Python”]

it fails, with the message:

“StartExternalSession::noinstall: No valid installations for system
Python were found with the options specified.”

Then I tried this:

StartExternalSession[<|“System” → “Python”, “Version” → “2.7.10”,
“Executable” → “/usr/bin/python”|>]

That too fails:

StartExternalSession::replFail: The process for external system Python
(/usr/bin/python) failed to start due to : no input returned from
process.

What could be the problem?

Regards,
Rangarajan

2

Hi,

I just found out how to solve the problem I reported earlier. I have to install the “pyzmq” package for Python.

I did the following from my shell:

sudo pip install pyzmq

After this, StartExternalSession[“Python”] works as expected.

Regards,

Rangarajan

3

I can confirm this as well. I have Ubuntu 18.04.2. Same fix worked for me.