I have installed python 3.3.6 and ipython 3.0.0 from source on my account. I am on a Linux cluster (RedHad4.9). When I start ipython I get the following message:
WARNING: Attempting to work in a virtualenv. If you encounter problems, please install IPython inside the virtualenv.
WARNING: IPython History requires SQLite, your history will not be saved.
I am not sure what a virtualenv
is, and why I am attempting to work in a virtualenv
.
I have been looking into this for a while but I cannot find a solution. Could anybody hint me the right way?
Since you installed python and iPython from source, this seems to be the best fix: A simple way to fix this would be to install Python in a non-root location, and use pip to install iPython. It's finding iPython in the global modules by not in the local modules, so it assumes you're using a virtualenv. Just use a pip install.
As for virtual environments, they're a virtual python install that restricts access to global modules so you can test custom modules, do other cool stuff. For example, you can activate and deactivate different environments. After installing one with (to the same directory):
Then I'm running in a virtualenv. Since iPython the command is found, but the global Python differs from the one installed, it gives me a warning though. https://virtualenv.pypa.io/en/latest/
Normally, if you're running a virtual environment, your shell should reflect this:
Without virtualenv:
With VirtualEnv:
EDIT:
Difference between local and global modules. The path with which Python searches for installed modules can be as follows:
This is in a virtual environment. See how the search path does not include /usr/lib, etc. If I deactivate my virtualenv and search globally, I get the following:
In here, everything besides the '' (current directory) is installed globally.