qp2/src/utils_cc/README.md

# Utils for CC

Utils for the CC modules.

## Contents
- Providers related to reference occupancy
- Integrals related to the reference
- Diis for CC (but can be used for something else if you provide your own error vector)
- Guess for CC amplitudes
- Routines to update the CC amplitudes
- Phase between to arbitrary determinants
- print of the qp edit wf

## Keywords
- cc_thresh_conv: Threshold for the convergence of the residual equations. Default: 1e-6.
- cc_max_iter: Maximum number of iterations. Default: 100.
- cc_diis_depth: Diis depth. Default: 8.
- cc_level_shift: Level shift for the CC. Default: 0.0.
- cc_level_shift_guess: Level shift for the MP guess of the amplitudes. Default: 0.0.
- cc_update_method: Method used to update the CC amplitudes. none -> normal, diis -> with diis. Default: diis.
- cc_guess_t1: Guess used to initialize the T1 amplitudes. none -> 0, MP -> perturbation theory, read -> read from disk. Default: MP.
- cc_guess_t2: Guess used to initialize the T2 amplitudes. none -> 0, MP -> perturbation theory, read -> read from disk. Default: MP.
- cc_write_t1: If true, it will write on disk the T1 amplitudes at the end of the calculation. Default: False.
- cc_write_t2: If true, it will write on disk the T2 amplitudes at the end of the calculation. Default: False.
- cc_par_t: If true, the CCSD(T) will be computed.
- cc_ref: Index of the reference determinant in psi_det for CC calculation. Default: 1.

## Org files
The org files are stored in the directory org in order to avoid overwriting on user changes.
The org files can be modified, to export the change to the source code, run
```
./TANGLE_org_mode.sh and 
mv *.irp.f ../.
```