Add converter for determinants coming from a PySCF CAS-CI or CAS-SCF calculation.

[amandadumi]

Proposed changes

This pull request extends the pyscf converter to support multideterminant wave functions coming from CAS-CI and CAS-SCF calculations.

What type(s) of changes does this code introduce?

• New feature
• Documentation or build script changes

Does this introduce a breaking change?

• No

What systems has this change been tested on?

Checklist

• linux workstation
• mac laptop

_Update the following with a yes where the items apply.

• Yes: This PR is up to date with current the current state of 'develop'
• n/a. Code added or changed in the PR has been clang-formatted
• Yes: This PR adds tests to cover any new code, or to catch a bug that is being fixed
• Yes: Documentation has been added (if appropriate)

[prckent]

Many thanks Amanda.

The test fails locally for me too, so this is not some CI quirk:

Start testing: May 24 10:21 EDT
----------------------------------------------------------
78/2619 Testing: converter_test_LiH_MSD_pyscf
78/2619 Test: converter_test_LiH_MSD_pyscf
Command: "/home/pk7/apps/spack/var/spack/environments/envgccnewmpi/.spack-env/view/bin/python3.11" "/home/pk7/projects/qmc/git_QMCPACK_prckent/build_pr/tests/converter/converter_test.py" "/home/pk7/projects/qmc/git_QMCPACK_prckent/build_pr/tests/converter/test_LiH_MSD_pyscf" "--exe" "/home/pk7/apps/spack/var/spack/environments/envgccnewmpi/.spack-env/view/bin/mpiexec -n 1 --bind-to none /home/pk7/projects/qmc/git_QMCPACK_prckent/build_pr/bin/convert4qmc" "--h5diff" "/home/pk7/apps/spack/var/spack/environments/envgccnewmpi/.spack-env/view/bin/h5diff"
Directory: /home/pk7/projects/qmc/git_QMCPACK_prckent/build_pr/tests/converter
"converter_test_LiH_MSD_pyscf" start time: May 24 10:21 EDT
Output:
----------------------------------------------------------
Unexpected number of inputs files (should be 1):  2
<end of output>
Test time =   0.04 sec
----------------------------------------------------------
Test Fail Reason:
Required regular expression not found. Regex=[  pass
]
"converter_test_LiH_MSD_pyscf" end time: May 24 10:21 EDT
"converter_test_LiH_MSD_pyscf" time elapsed: 00:00:00
----------------------------------------------------------

End testing: May 24 10:21 EDT

[prckent]

Test this please

[prckent]

Looks good to me (LGTM)

I did a determinants only run to check the energy of the wavefunction ( 1000 blocks of 10000 steps, 48 walkers, 8 substeps, 0.5 timestep, 400 warmup) and got a good match:

 LiH.pyscf.out:CASCI E = -7.98378359954454  E(CI) = -1.08000501124573  S^2 = 0.0000000
$qmca -q ev try.s000.scalar.dat 
                            LocalEnergy               Variance           ratio 
try  series 0  -7.983708 +/- 0.000354   6.329815 +/- 0.471319   0.7928 

[prckent]

Test this please

[prckent]

Quick note that I did some tests filtering down to a single determinant. For this case the energy is still very close to the CASCI energy since the excited state determinants don't find much correlation energy in LiH. => It will be good to see this used in some more real world cases and know the energies match.