qiskit-community / ffsim

Faster simulations of fermionic quantum circuits.
https://qiskit-community.github.io/ffsim/
Apache License 2.0
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Change RDM interface to be more space efficient and consistent with PySCF #246

Closed kevinsung closed 2 weeks ago

kevinsung commented 2 weeks ago

In the rdm function, setting spin_summed=False results in an expanded tensor with many zeros. For example, a 1-RDM will be block diagonal. I think we should change this to return, for example, a pair of RDMs, as the make_rdm1s function from PySCF does.

slater_determinant_rdm should also be updated.