implement isrmatrix_vector_product

[apapapostolou]

Implement and test the matrix-vector product of an ISR one-particle operator through second order in perturbation theory. Both symmetric and asymmetric one-particle operators are allowed.

[maxscheurer]

Thanks for the contribution. I think the implementation should be in line with the AdcMatrix code structure. So one would need to re-group the equations into blocks and then basically copy/paste into the scaffold of the AdcMatrix code. I guess it won't be too much work ☺️

[maxscheurer]

This looks really good! Just a few comments, tests look good to me. After addressing the comments, we can merge this 🚀

[maxscheurer]

This looks great! 👍
You want to give this another look, @mfherbst?

[maxscheurer]

@apapapostolou It would be great if you could try to update the TPA example using your new IsrMatrix instead of the transition densities?

[maxscheurer]

Thanks a lot for updating the example @apapapostolou 🚀

[maxscheurer]

Is this ready from your side, @apapapostolou? 😄

[apapapostolou]

Is this ready from your side, @apapapostolou? 😄

Yes, it is 😄

[maxscheurer]

@apapapostolou feel free to create a PR and add yourself to the contributors/authors! 😬
These are listed in setup.py and adcc/__init__.py