Pyscf

* Added
- SA-CASSCF Nonadiabatic Coupling Vectors
- The to_gpu function to convert pyscf objects to gpu4pyscf objects.
- 4th, and 5th order XC derivatives.
* Improved
- DIIS with damping for gapless systems.
- CPHF solver with level shift for gapless systems.
- The memory footprint for rsdf_builder and rsjk_builder.
- Use UHF natural orbital for RHF chkfile initial guess.
- Pipek Mezey + Stability check using Jacobi sweep.
- The conversion between FCI strings and addresses for more than 64 orbitals.
- The interface to the dftd3 and dftd4 dispersion correction modules.
- Switch off the sparsity treatment in DFT numerical integration for small system.
- Lattice-sum cutoff for non-orthogonal cell.
- Allow turning off AO symmetry for PBC DFT.
* Fixes
- cp2k basis parsers
- k2gamma for dft classes.
- Mole.magmom attribute serialization error.
- post-hf Gradients with Cartesian GTOs.
- Basis order problem in molden.load .
- PBC DFT Becke grids rounding error.
- PBC rsdf for un-sorted basis.
- The get_bands function with k-point symmetry.

* Added
- Mulliken population analysis for KGHF.
- Interface to libmsym (https://github.com/mcodev31/libmsym) for handeling non-abelian symmetry.
- A variant of the Hückel initial SCF guess.
- PBC TDDFT with non-zero particle-hole momentum transfer for GDF/RSDF (same as the kshift used in pbc eom-ee-ccsd).
- PBC TDDFT with twisted boundary conditions (both single k-point and k-point mesh).
- NVT Molecular Dynamics.
- Gaussian charge model for int1e_grids.
- GHF with fractional occupancy.
- FCIDUMP for MCSCF orbitals.
- DF-CCSD and frozen core for FNO-CCSD.
- multi-collinear functional for PBC DFT.
- non-local functional (VV10) for PBC DFT.
- "undo" method for dynamic classes. This method can revert the action for conversion methods such as "density_fit()", "x2c()", "newton()", "as_scanner()", etc..
- Merged basis parser for molecular GTO basis and GTH basis. GTH basis can be assigned to Mole object directly.
- Merged ECP and PP parser. PP can be assigned to Mole object directly.
- C-PCM, IEF-PCM, COSMO, and SS(V)PE solvent models and their Gradients.
* Improved
- Performance of the gradients of nuclear repulsion energy.
- JK builder for short-range ERIs.
- The layout of the Mole class and Cell class. Remove the inheritance between Cell and Mole.
- The layout of various SCF classes and the conversion methods (to_ks, to_hf, to_uhf, to_ghf, etc.) between different SCF objects.
- The layout of various MCSCF classes.
- New style to generate dynamic class for DF methods, X2C, QMMM, SOSCF, Solvent model, StateAverageMCSCF, Scanner methods, etc.
- SCF smearing method.
- Make Mole and Cell object picklable.
* Fixes
- supercell symmetry.
- NAO orbital localization.
- Finite-size correction for PBC TDDFT (1/Nk convergence to TDL and agreement with molecular code).
- Bugs in FCI for num. orbitals >= 64.
- PBC empty cell error.
- The edge case CAS(2,2) for Selected CI.
- Dimension issue in PBC-GDF cderi tensor.
- Assume 46 and 78 core configurations to be f-in-valence.

* Added
- Gaussian MM charges
- Stepsize scheduler for UCASSCF
- APC active space selection
- f-in-core ECPs and core configurations
- TDDFT gradients for triplet states
- Support complex-valued h1e in fci_slow.absorb_h1e
* Improved
- Update B3LYP functional to make it behave the same to Gaussian
- Disable CLI parser by default
- Accuracy and performance of RSDF, GDF and RSJK methods
- get_lattice_Ls, and energy cutoff estimation
- Performance of PBC-AFTDF get_k method
- BCCD with semi-canonicalized orbitals
- Smearing in the molecular ROHF method
- Refactors FCI cylindrical symmetry implementation and improves its stability and performance
- Update interface of geomeTRIC library to support initial hessian
- NLC parser and NLC integral code
* Fixes
- Update ddCOSMO functional to make it behave the same to Gaussian
- Deprecated keywords when calling scipy.linalg.solve
- The numerical issue in df hessian when the overlap matrix is ill-conditioned
- PBC-DFT eval_rho2 method
- xc parser for hybrid LDA functional
- SACASSCF grad fcasscf right track nelecas
- density fitting for GHF objects
- Fix bug in MP2 gradients scanner

* Added
- Density fitting gradients and hessian for RSH functionals
- SCS-MP2 and SCS-KMP2
- Configurations of f-in-core ECPs
- ao2mo integral transformation for GHF orbitals with scalar ERIs
- Interface to access basis Set Exchange DB
- DF-UCISD
- Moment resolved GF-CCSD
- MOM (maximum overlap method) for GHF and DHF
* Improved
- PBC GDF K-build performance
- Read cubegen for crystalline systems
* Fixes
- Outdated examples
- Update to libcint 5.3.0 to filter warning messages produced by 5.2.0
- PBC density fitting CDERIArray object backward compatibility
- DIIS numerical instability
- C2v molecule orientation when symmetry is enabled
- The missed HF exchange in RSH functional wB97
- Gauge origin of Boys localization
- Check the root numbers during Davidson diagonalization iterations
- Removed hard-coded environment variable MKL_NUM_THREADS=1
- Conflicts in GDF cderi tensor for RSH functionals

* Added
- Molecular nuc grad with DF ERIs for ROHF, ROKS, CASSCF, SA-CASSCF
- K-point symmetry adapted crystalline orbital basis
- K-point symmetry for GDF, MDF, KCCSD
- VV10 gradients
- Spin density population analysis for MCSCF
- BCCD
- Cylindrical symmetry for FCI wavefunction
- Use a linearly independent basis in DIIS
- Full CI for complex integrals
- Maxwell-Boltzmann Velocity Distribution in BOMD
* Improved
- PBC integral accuracy for GDF, MDF, FFT, AFT
- PBC integral accuracy of 2D system for insufficient integral grids
- Update Libxc to Libxc-6
- get_monkhorst_pack_size for numerical noise
- Unit recognization unified
* Fixed
- MCSCF without initializing SCF
- Memory leaks in C kernels for CCSD(T)
- Fully spin-polarized UMP2, DF-UMP2, UCCSD, UCCSD(T) bugfixes
- numpy_helper.hermi_sum for non-contiguous array
- Padding and frozen orbitals bugs in KMP2
- PolEmbed interface and CASCI with PE
- Molecular density fitting hessian
- K-point symmetry adapted KS-DFT with SOSCF solvers

* Added
- CDERIArray class to load PBC GDF tensor
* Improved
- MCSCF fix_spin_ as a class for SA-CASSCF gradient compatibility
- PBC GDF and MDF accuracy
- PBC X2C hcore integrals performance
* Fixed
- Integral screening bug in ft_ao
- EOM-EE RCCSD intermediates
- MGGA fully polarized system bug