Notebooks enabled for Google colab ("No local install" needed)

[alexfleury-sb]

Here are the highlights. Do you have feedbacks about doing the same thing with other notebooks and the pip command (use of pip install tangelo-gc, etc.)?

• Added a cell at the beginning of the adapt, classical_shadows, dmet, oniom, vqe and vqe_custom notebooks:

try
    import tangelo
except ModuleNotFoundError:
    !pip install git+https://github.com/goodchemistryco/Tangelo.git@develop --quiet

• Removed an unused "import google" in overview notebook.
• The adapt notebook was not up-to-date with the last changes. It can be ran now.

Here are the GColab links (the links are coming from my fork for now):

Notebook	GColab link
VQE	https://colab.research.google.com/github/AlexandreF-1qbit/Tangelo/blob/gcolab/examples/vqe.ipynb
Custom VQE	https://colab.research.google.com/github/AlexandreF-1qbit/Tangelo/blob/gcolab/examples/vqe_custom_ansatz_hamiltonian.ipynb
ADAPT-VQE	https://colab.research.google.com/github/AlexandreF-1qbit/Tangelo/blob/gcolab/examples/adapt.ipynb
DMET	https://colab.research.google.com/github/AlexandreF-1qbit/Tangelo/blob/gcolab/examples/dmet.ipynb
ONIOM	https://colab.research.google.com/github/AlexandreF-1qbit/Tangelo/blob/gcolab/examples/oniom.ipynb
Classical Shadows	https://colab.research.google.com/github/AlexandreF-1qbit/Tangelo/blob/gcolab/examples/classical_shadows.ipynb

[ValentinS4t1qbit]

A few comments:

• For each notebook, make sure the cell is preceded by a sentence that makes things look natural. For example, in the VQE and DMET notebook, there's a sentence that says "In order to run this notebook, you need...": the cell would be perfect afterwards. If such a sentence does not exist, you can add one.

• We need to add stuff to README.rst in the tutorials section (or refer to TUTORIALS.rst) telling how users can turn any notebook from our repo into google collab ones, and points to useful basic info about google collab (you're also educating us).

• Don't forget about the linq notebooks

[alexfleury-sb]

2 points that could need a discussion:

• I added a sentence (copy/pasted) from the VQE notebook before every installation cell.
  This notebook assumes that you already have installed Tangelo in your Python environment, or have updated your Python path so that the imports can be resolved. If not, executing the cell below installs the minimal requirements for this notebook.
• The linq notebooks have an "installation" cell now. I also install the qiskit, braket and qulacs packages at the same time. Therefore, all cell with projectq and qdk will fail. Is it bad considering there is already a warning Here are a few examples. Some cells may fail depending on what packages you have installed.? The other option is to convert the failing cells to markdown.

[ValentinS4t1qbit]

Thank you Alexandre, I have learnt a lot from your exploration and notes