Export wave functions to CHAMP

The excited states are of different symmetries, so we will generate two different setups in CHAMP, one for each state. To do that, we will save two different files, one for each state, and containing only the non-zero determinants.

First, copy the COH2 directory into COH2_GS and COH2_ES, one directory for each state:

cp -r COH2 COH2_GS
cp -r COH2 COH2_ES

Then, we will use qp_edit to extract one state in each EZFIO directory:

qp set_file COH2_GS
qp edit --state=1

qp set_file COH2_ES
qp edit --state=2

The states have been extracted, but the EZFIO databases still contain the determinants with almost zero coefficients. We can remove them by running

qp set_file COH2_GS
qp run truncate_wf

This last program is interactive and asks for the minimum weight of the kept configurations. Answer 1.d-10 to this question.

Similarly, remove the negligible determinants from the excited state:

qp set_file COH2_ES
qp run truncate_wf

We can now export the wave functions in two different TREXIO files. To do that, for each state we copy the initial TREXIO file and add the determinants information:

cp COH2.trexio COH2_GS.trexio
qp set_file COH2_GS
qp set trexio trexio_file  COH2_GS.trexio
qp run export_trexio

cp COH2.trexio COH2_ES.trexio
qp set_file COH2_ES
qp set trexio trexio_file  COH2_ES.trexio
qp run export_trexio

Now, we are ready to run the QMC calculations for each state.