TODO list for TREX-IO: to make a pull request to the main repository in the future.

[kousuke-nakano]

Dear @sunqm, @scemama, @q-posev, and @NastaMauger. I would like to complete the TREX-IO implementation so that we can make a pull request to the main repository in the future. Here is a TODO list. I would appreciate it if you could comment on and supplement it if I've missed anything else.

[Writing]

• _scf_to_trexio: Complex wavefunctions and twisted-average are missing.
• _cc_to_trexio: NotImplementedError -> We have to implement a writer corresponding to TREX-IO doc. 5.3. Amplitudes (amplitude group).
• _mcscf_to_trexio: NotImplementedError -> We have to implement a writer corresponding to TREX-IO doc. 5.2. Configuration state functions (csf group)?
• det_to_trexio -> we should not import from trexio_tools.group_tools import determinant as trexio_det; otherwise, pyscf depends on trexio_tools. We should hardcode it
• write_eri (write_mo_2e_int_eri) -> Is it completed?
• write_eri -> Those for ao_1e_int, ao_2e_int, and mo_1e_int are not needed?
• Does to_segment_contraction (all-electron cc-pVXZ) work?
• We have to implement a writer corresponding to TREX-IO doc. 5.4. Reduced density matrices (rdm group)

[Reading]

• mol_from_trexio: The ECP implementation if trexio.has_ecp(tf) is missing.
• scf_from_trexio: assert mo.shape == (nao, nao) -> Only RHY is supported. UHF and ROHF should be implemented.
• read_det_trexio -> Is it completed?
• read_eri (read_mo_2e_int_eri) -> Is it completed?
• read_eri -> Those for ao_1e_int, ao_2e_int, and mo_1e_int are not needed?
• We have to implement a reader corresponding to TREX-IO doc. 5.4. Reduced density matrices (rdm group)

[Test suites]

• Consistency checks between reading and writing for all functions

[q-posev]

Great idea, thank you @kousuke-nakano !

I would say that the MO integrals writing is almost complete. I did some tests in the past and was able to reproduce the HF energy by reading the integrals from TREXIO files produced by QP2 and PySCF (taking into account the chemists/physicist notations, but this will be fixed once PR #92 is merged). Perhaps we are fine with not storing the AO integrals since we have the MO coefficients and we probably do not want to duplicate the same integrals in both AO and MO basis.

[scemama]

Thanks @kousuke-nakano !

I think it is important to store also the AO integrals, because it is the starting point for many codes. I have somewhere a script where I write the AOs integrals of PySCF in a trexio file if needed.

[kousuke-nakano]

Dear @NastaMauger, @scemama, and @q-posev,

Thank you for the replies and reactions!

I am working on this issue in my forked repository. I have implemented a reading function for UHF wavefunctions, a reading function for ECPs, and writing and reading functions for complex WFs (with PBC). I have also improved the test suits. The remaining tasks are read_eri and write_eri for AOs.

I noticed that read_mo_2e_int_eri (write_eri and read_eri are renamed with write_mo_2e_int_eri and write_mo_2e_int_eri, respectively, because I will implement *_ao_2e_int soon) did not work for UHF wavefunctions (please uncomment lines 160--163 of def test_mf_uhf_ae_6_31g(cart): in test_trexio.py) and PBC wavefunctions (please uncomment lines 195--197 of def test_mf_k_gamma_rhf_ae_6_31g(cart): in test_trexio.py). I will try to solve these issues tomorrow, but if you provide me with any hints, I will greatly appreciate it.

[kousuke-nakano]

[Writing]

• [Completed] _scf_to_trexio: Complex wavefunctions and twisted-average are missing.
• [Not needed?]_cc_to_trexio: NotImplementedError -> We have to implement a writer corresponding to TREX-IO doc. 5.3. Amplitudes (amplitude group).
• [Completed ]_mcscf_to_trexio: NotImplementedError -> We have to implement a writer corresponding to TREX-IO doc. 5.2. Configuration state functions (csf group)?
• [Completed]det_to_trexio -> we should not import from trexio_tools.group_tools import determinant as trexio_det; otherwise, pyscf depends on trexio_tools. We should hardcode it
• [WIP] write_eri (write_mo_2e_int_eri) -> Is it completed?
• [WIP] write_eri -> Those for ao_1e_int, ao_2e_int, and mo_1e_int are not needed?
• [Completed] Does to_segment_contraction (all-electron cc-pVXZ) work?
• [Not Needed?] We have to implement a writer corresponding to TREX-IO doc. 5.4. Reduced density matrices (rdm group)

[Reading]

• [Completed] mol_from_trexio: The ECP implementation if trexio.has_ecp(tf) is missing.
• [Completed] scf_from_trexio: assert mo.shape == (nao, nao) -> Only RHY is supported. UHF and ROHF should be implemented.
• [Completed] read_det_trexio -> Is it completed?
• [WIP]read_eri (read_mo_2e_int_eri) -> Is it completed?
• [WIP]read_eri -> Those for ao_1e_int, ao_2e_int, and mo_1e_int are not needed?
• [Not needed?] We have to implement a reader corresponding to TREX-IO doc. 5.4. Reduced density matrices (rdm group)

[Test suites]

• [WIP] Consistency checks between reading and writing for all functions

[kousuke-nakano]

Updated #160.

[Writing]

• [Completed] _scf_to_trexio: Complex wavefunctions and twisted-average are missing.
• [Not needed]_cc_to_trexio: NotImplementedError -> We have to implement a writer corresponding to TREX-IO doc. 5.3. Amplitudes (amplitude group).
• [Completed]_mcscf_to_trexio: NotImplementedError -> We have to implement a writer corresponding to TREX-IO doc. 5.2. Configuration state functions (csf group)?
• [Completed]det_to_trexio -> we should not import from trexio_tools.group_tools import determinant as trexio_det; otherwise, pyscf depends on trexio_tools. We should hardcode it
• [WIP in another branch] write_eri (write_mo_2e_int_eri) -> Completed. Another pull-request.
• [WIP in another branch] write_eri -> Completed. Another pull-request.
• [Completed] Does to_segment_contraction (all-electron cc-pVXZ) work?
• [Not needed] We have to implement a writer corresponding to TREX-IO doc. 5.4. Reduced density matrices (rdm group)

[Reading]

• [Completed] mol_from_trexio: The ECP implementation if trexio.has_ecp(tf) is missing.
• [Completed] scf_from_trexio: assert mo.shape == (nao, nao) -> Only RHY is supported. UHF and ROHF should be implemented.
• [Not needed] read_det_trexio -> reading eri will not be implemented.
• [Not needed] read_eri (read_mo_2e_int_eri) -> reading eri will not be implemented.
• [Not needed] read_eri -> reading eri will not be implemented.
• [Not needed] We have to implement a reader corresponding to TREX-IO doc. 5.4. Reduced density matrices (rdm group)

[Test suites]

• [Completed] Consistency checks between reading and writing for all functions