I would like to print the CI coefficients after performing a DMRG-SCF simulation.
The output file contains the coefficients of the important determinants by default in CASSCF simulations. It is also possible to print all coefficients by changing the number of important determinants using num_dets_print. However, this does not seem to work in DMRG-SCF simulations.
Also, I found a function called getFCIcoefficient in the library of DMRG.h. However, I am getting a NameError message when I tried to use this function as follows
H 1 0.9618
H 1 0.9618 2 102.425
dmrg_irrep 0 dmrg_multiplicity 1 restricted_docc [1, 0, 0, 0] active [4, 0, 1, 3] dmrg_sweep_states [ 200, 500, 1000, 1000 ] dmrg_sweep_energy_conv [ 1e-8, 1e-8, 1e-8, 1e-8 ] dmrg_sweep_dvdson_rtol [ 1e-4, 1e-4, 1e-4, 1e-4 ] dmrg_sweep_max_sweeps [ 5, 5, 5, 100 ] dmrg_sweep_noise_prefac [ 0.03, 0.03, 0.03, 0.0 ]
scf_e, scf_wfn = energy(‘dmrg-scf’, return_wfn=True)
cicoeff1 = getFCIcoefficient([1,1,0,0,1,1,1,0],[1,1,0,0,1,1,1,0],False)
Finally, I tried to follow the method suggested in a previous post. Although the printed number of determinants is correct, all the coefficients appear to be zero.
Is there a method that prints the converged CI vector with the corresponding determinant indices after a DMRG-SCF simulation?
Thank you in advance.