Why pip does not install a package?

Question

pip install indicates that the nitime package was successfully installed but it is not. Why is this?

$ pip3 install nitime
Defaulting to user installation because normal site-packages is not writeable
Collecting nitime
  Using cached nitime-0.9.tar.gz (6.2 MB)
  Preparing metadata (setup.py) ... done
Requirement already satisfied: numpy in ./.local/lib/python3.8/site-packages (from nitime) (1.22.3)
Requirement already satisfied: cython in /usr/lib64/python3.8/site-packages (from nitime) (0.29.14)
Requirement already satisfied: scipy in ./.local/lib/python3.8/site-packages (from nitime) (1.8.0)
Requirement already satisfied: matplotlib in /usr/lib64/python3.8/site-packages (from nitime) (3.2.2)
Requirement already satisfied: networkx in /usr/lib/python3.8/site-packages (from nitime) (2.5)
Requirement already satisfied: nibabel in ./.local/lib/python3.8/site-packages (from nitime) (3.2.2)
Requirement already satisfied: cycler>=0.10 in /usr/lib/python3.8/site-packages (from matplotlib->nitime) (0.10.0)
Requirement already satisfied: kiwisolver>=1.0.1 in /usr/lib64/python3.8/site-packages (from matplotlib->nitime) (1.3.1)
Requirement already satisfied: pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1 in /usr/lib/python3.8/site-packages (from matplotlib->nitime) (2.4.7)
Requirement already satisfied: python-dateutil>=2.1 in ./.local/lib/python3.8/site-packages (from matplotlib->nitime) (2.8.2)
Requirement already satisfied: decorator>=4.3.0 in /usr/lib/python3.8/site-packages (from networkx->nitime) (4.4.0)
Requirement already satisfied: packaging>=14.3 in ./.local/lib/python3.8/site-packages (from nibabel->nitime) (21.3)
Requirement already satisfied: setuptools in ./.local/lib/python3.8/site-packages (from nibabel->nitime) (60.6.0)
Requirement already satisfied: six in /usr/lib/python3.8/site-packages (from cycler>=0.10->matplotlib->nitime) (1.14.0)
Using legacy 'setup.py install' for nitime, since package 'wheel' is not installed.
Installing collected packages: nitime
  Running setup.py install for nitime ... done
Successfully installed nitime
$ pip3 show nitime
WARNING: Package(s) not found: nitime
$ python3 -c "import nitime"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'nitime'


$ pip3 show pip
Name: pip
Version: 22.0.4
Summary: The PyPA recommended tool for installing Python packages.
Home-page: https://pip.pypa.io/
Author: The pip developers
Author-email: [email protected]
License: MIT
Location: /home/servoz/.local/lib/python3.8/site-packages
Requires: 
Required-by: 
$ uname -a
Linux 5.11.22-100.fc32.x86_64 #1 SMP Wed May 19 18:58:25 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
$ python3 -V
Python 3.8.10

EDIT: Ok! I managed to install using dnf install python3-nitime (fedora).

I don't really understand why pip doesn't work with nitime on fedora ...

Answer 1

This may be because of conflicts with other packages, so try doing this in a new environment. Try creating a virtual environment. Install virtualenv using this:

pip install virtualenv

Create a virtual environment named venv using this:

virtualenv venv

To activate the virtual environment, use this:

source ./venv/bin/activate

Try installing nitime now:

pip3 install nitime

Done!

You can deactivate the virtual environment using this:

deactivate