Release notes

Version v0.13.1 - 2024.07.11

DIIS.perform has been changed to DIIS.perform! in order to allow to read the vectors and residuals as Vector{}.
The signature of newmmap function has changed (the type specification is now the last argument and defaults to Float64.
The FciDump module has been renamed to FciDumps.
The FDump type has been changed to FDump{N} with N=3 (for triangular storage of 2-electron integrals) or 4. The logical variable triang has been removed (there is a function is_triang(::FDump) now). Aliases TFDump = FDump{3} and QFDump = FDump{4} have been introduced.
The ECInfo type now accepts only FDump{3}. The FDump{4} objects have to be transformed first (the transformation functions are not implemented yet).
The triangular functions have been moved to a separate file utensors.jl, part of the QMTensors module. uppertriangular function has been renamed to uppertriangular_index.
The driver functions and macros now return energies in an ordered descriptive dictionary OutDict=ODDict{String,Float64}. Use last_energy function to access the last energy (or last to access the whole entry including the key and the description).

Save the memory using in Hessian matrix calculation in dfmcscf function.
dfdump stores the MO integrals internally in mmaped files.
The header of the FDump is now stored in a type-stable structure FDumpHeader.

Export of molden files (@export_molden). At the moment the orbital energies and occupations are not exported.
Add dfmcscf part in documentation
CCSDT and DC-CCSDT closed-shell implementations generated with Quantwo.
QMTensors.SpinMatrix struct for one-electron matrices (e.g., MO coefficients)
An ordered descriptive dictionary for energy outputs (ODDict) has been implemented. Each key-value entry can have a description.
DIIS.perform! now accepts a tuple of functions to calculate cusomized dot-products (e.g., involving contravariants etc).

use SVD in DIIS.
increase number of iterations in 2D-CCSD IAS test.
interface to libcint_jll has been implemented. The basis set library is added (in Molpro format), and basis sets are parsed to a BasisSet object. GaussianBasis.jl dependency is removed.

Expand README
amdmkl() function to speed up MKL on AMD machines.
CROP-DIIS option (JCTC 11, 1518 (2015)) which is less sensitive to the DIIS dimension. To activate, set diis option crop=true, the DIIS dimension can be changed using maxcrop (default is 3).
An option print_init is added to the @print_input macro (default is false). If set to true, the ElemCo.jl info is printed again (useful if the output is redirected in julia to a file).
A simple DMRG routine is added based on ITensors (adapted from ITensorChemistry.jl).
A Molpro interface to import matrop matrices (orbitals or overlap).

Get rid of error message from git if .git is not available (e.g., in the case of the released version).
Sort orblist, which fixes issues if user occupations are not provided in a sorted list.
Fix amplitudes before Hylleraas energy calculation for FR-CC, which will properly report the energy in a (2,2) (single iteration) calculation.

EC.ms (previously of type MSys) in ECInfo is renamed to EC.system (of type AbstractSystem).
ECdriver routine is moved to CCDriver module and renamed to ccdriver. The fcidump keyword-argument is now empty by default. It doesn't accept list of methods anymore, only one method at a time.
The driver routines and macros return energies as NamedTuple.
The SVD methods have to be called now as SVD-<methodname>, e.g., svd-dcsd.
The @svdcc macro is renamed to @dfcc macro and calls the dfccdriver routine, which is intended as a driver routine for all DF-based correlation methods (i.e., methods which don't use the EC.fd integrals).

Renamed function active_orbitals to oss_active_orbitals.
Renamed function calc_ccsd_resid to calc_cc_resid.
ECdriver and oss_active_orbitals now return named tuples.
Improved documentation of occupation strings syntax.
Switched to Atom and FlexibleSystem from AtomsBase as the internal representation of the molecular system. The basis set is stored for each atom as :basis property (as Dict{String,String}, e.g., system[1][:basis]["ao"]). One can also set :basis property for the whole system.
Renamed macro @opt to @set. @opt is now an alias of @set.

The automatically generated UCCSDT and UDC-CCSDT methods have been added to the docs.
SCS-MP2, SCS-CCSD and SCS-DCSD

Cholesky threshold thr is used for integral decomposition only. Threshold for elimination of redundancies is now called thred.
Files for amplitudes and multipliers are now called ..._1, ..._2,... for singles, doubles, etc.

Fix dressing of a three-internal integral (which slightly affected the energy of CCSD/DCSD with use_kext=false).

Add various methods (DF-[U]HF, BO-[U]HF, [U/R]CCSD, [U/R]DCSD, SVD-DCSD, SVD-DC-CCSDT, CCSD(T), ΛCCSD(T), ΛDCSD...).
Setup macros, options etc.
...