Installation method not working

[SamarthH]

Information

• Qiskit Terra version:
• Python version:
• Operating system:

What is the current behavior?

Installation is via python3 -m pip install .
This leads to an uneditable install, and causes cython based modules to not work

Steps to reproduce the problem

Install with python3 -m pip install .
Run the example code

What is the expected behavior?

Cython based packages work

Suggested solutions

Replace installation command with python3 -m pip install -e .
This solves the issue

[biplab37]

For common use editable option is not needed. The option is important for developer who would like to test the code while making changes to it.
The problem with the cython based module, if I can remember correctly, can be solved by running the installation command twice.

 python3 -m pip install .

I am not sure about the reason for this behaviour. Let me know if you find something and I will update the readme file accordingly.