cvxopt issues on El Capitan about pygsti

[jarthurgross]

It appears that the issue was that I had installed cvxopt via conda install cvxopt instead of pip install cvxopt. Once I install with pip, all the ImportErrors disappear. This should be mentioned in the documentation somewhere (especially since @kmrudin seems to have experienced similar issues with Enthought Canopy).

[Travis-S]

Is there some way to include these kinds of subtleties in the dependencies? As of devlop/c34ba68a590e5ad8d1adf7cf7ca840e246770c77, requirements.txt doesn't list cvxopt as a dependency.

[jarthurgross]

cvxopt is a dependency of cvxpy, which is an optional dependency for pyGSTi (it's only used to compute the diamond-norm I believe), which I think is why it's not in requirements.txt. As far as including the subtlety of using pip versus conda, I don't know of a way. If it installs via setup.py, I believe any dependencies listed in there are installed using pip.

[LSaldyt]

Just for reference:

Documentation for cvxpy indicates that mixing pip and conda installs can cause errors (especially if pip install --upgrade is used when the package was originally installed with conda).
In #6, the conda-installed version of cvxopt was preventing computing the diamond norm. Specifically, the version 1.8.1 py_35 needed to be updated to 1.8.1 py35_blas_openblas_203 [blas_openblas] conda-forge or downgraded to 1.7.1 py_35. For me, the pip version worked as well.