Odometer tester

[alnaba1]

@msricher Made a test for odometer one spin for H2 system in the minimal basis, I would expect that when we pass cost of the orbitals as energies: [0.74587179 1.10115033], if q_max is bigger than 0.75 it would select only the first determinant. If it is bigger than 1.2, it would select all determinants.

Currently, selecting a value lower than 0.74, doesn't select any determinant as expected. However, if it is bigger than 1.2 currently then we get an index error (or a segmentation fault error when we tried with the H4 system). Can you help to figure out what's going on?

[msricher]

It's because you are using a fullci_wfn, for which the arguments to add_occs are a (2, $N_\text{up}$) ndarray of c_ints. I changed your code in pyci/utility.py to (starting from line 176)

    # Select determinants
    while True:
        if new[-1] < wfn.nbasis and (np.sum(cost[new]) + t * cost[new[-1]]) < qmax:
            # Accept determinant and go back to last particle
            wfn.add_occs(np.vstack((new, new)))
            j = wfn.nocc_up - 1
        else:
            # Reject determinant and cycle j
            new[:] = old
            j -= 1
...

and it works:

[1+]-[*36-cost-tester]-[michelle@t14s-g4]-[~/Git/pyci]-% pytest -sv pyci/test/test_odometer.py
================================================= test session starts =================================================
platform linux -- Python 3.11.8, pytest-7.4.4, pluggy-1.3.0 -- /home/michelle/Git/venv/bin/python
cachedir: .pytest_cache
rootdir: /home/michelle/Git/pyci
plugins: anyio-4.2.0
collecting ... converged SCF energy = -1.06610864931794
converged SCF energy = -1.06610864931794
converged SCF energy = -2.09854593699772
collected 3 items                                                                                                     

pyci/test/test_odometer.py::test_odometer_one_spin[wfn0-cost0-0-0.7] PASSED
pyci/test/test_odometer.py::test_odometer_one_spin[wfn1-cost1-0-1.0] PASSED
pyci/test/test_odometer.py::test_odometer_one_spin[wfn2-cost2-0-1.2] PASSED

================================================== 3 passed in 0.72s ==================================================

You should check if the wfn instance is a one-spin (doci or genci) or two-spin (fullci) and if it's two-spin, do as I showed here.

[msricher]

Actually an easier solution is just, start with a doci_wfn, run your odometer algorithm to fill it, and then upcast it to a fullci_wfn:

wfn = pyci.doci_wfn(nbasis, n_up, n_dn)
# fill `wfn`
# ...
wfn = pyci.fullci_wfn(wfn)

You can upcast {doci,fullci}_wfn to genci_wfn, and doci_wfn to fullci_wfn. This involves copying the wfn, though, so if it's a gigantic wfn (billions of dets) this isn't a good idea.

[alnaba1]

@msricher Is there a simple way of checking if the wfn instance is one-spin or two-spin? I've updated the Odometer algorithm to check the type of the wfn object using isinstance() but it doesn't seem elegant.

My concern with doing it this way is that we have to list out every possible type of wfn object and check if the instance of wfn is of the one-spin or two-spin type, and I'm not sure if there would be more types of wfn objects that would be implemented later and not be included in the types I have currently listed.

    if isinstance(wfn, pyci.fullci_wfn):
        two_spin = True
    elif isinstance(wfn, (pyci.doci_wfn, pyci.genci_wfn)):
        two_spin = False
    else:
        raise TypeError
    while True:
        if new[-1] < wfn.nbasis and (np.sum(cost[new]) + t * cost[new[-1]]) < qmax:
            # Accept determinant and go back to last particle
            if two_spin:
                wfn.add_occs(np.vstack((new, new)))
            else:
                wfn.add_occs(new)

[msricher]

This is fine, there's only three classes, so you can check this way. There won't be more added.

[msricher]

You can also just use the abstract superclasses pyci.one_spin_wfn and pyci.two_spin_wfn. isinstance(dociwfn, pyci.one_spin_wfn) should be true etc.

[msricher]

This looks ok to me. If the tests run, you can merge it, although I'm not as familiar with this work being done, so I'd wait for Rik to approve it.

Can you rename the h{2,4}.fcidump files to specify the basis set? E.g. h2_sto3g.fcidump.

[RichRick1]

Good job! There are few things that needs to be fixed:

1. I don't think there is a need to check a way function type in the odometer_one_spin algorithm. It is used only for the one_spin wavefunction and this can be checked directly in the test function when odometer_one_spin or odometer_two_spin is called.
2. Test if the expected orbitals are selected when custom cost is provided
3. Fix the test that throws the error on GH action. There is something wrong with a missing file

[alnaba1]

All finished, ready to merge.

[msricher]

OK, yes this is ready to be merged. Can you just rebase it on master? Then I'll merge it.

[alnaba1]

OK, yes this is ready to be merged. Can you just rebase it on master? Then I'll merge it.

@msricher All done.