PySCF 2.9.0 (2025-04-20)
------------------------
* Added
  - Analytical PCM Hessian
  - Density fitting UCCSD
  - A general driver for finite difference gradients and hessian
* Improved
  - Assign default auxiliary basis for def2-mtzvp and def2-mtzvpp
  - Better initial guess for smearing
  - libxc interface for passing omega in composite functionals
  - The tolerance in geometry when identifying point group symmetry
  - Adjust PBC GDF eigenvalue decomposition accuracy
  - Special treatment in PBC GDF for dimension=0 systems
  - The density matrices computation performance of fci_dhf_slow
* Fixes
  - Dimension bug in spinor X2C code
  - C-PCM and SS(V)PE gradients
  - Complex density matrices for DFHF
  - Fixes COSMO-RS functionality
  - DF auxiliary basis assignment for ghost atoms
  - Lattice sum range issue for low-dimensional systems
  - The precision when dumping molecular geometry in fromfile/fromstring function
  - kpts_band in the rsdf method.


PySCF 2.8.0 (2025-01-14)
------------------------
* Added
  - The ccpy extension (https://github.com/piecuch-group/ccpy) which enables various Coupled cluster methods
  - COSMO-RS functionality
  - DFMP2 and RPA for UHF reference
  - Add functions to read and write Cell geometry, allowing Direct or Cartesian in VASP input
  - Add def2-mtzvp and def2-mtzvpp basis sets for 3c methods
  - libqcschema module to load qcschema json
* Improved
  - Integral screening for Gaunt and Breit term
  - Performance and multi-threading efficiency of DFMP2 and RPA, gaining 4x - 8x speedups
  - Stability analysis for extended system, matching with molecular version
  - Update to Libxc 7.0
  - Adjust TDDFT amplitudes to follow the CIS convention
  - Accelerate DFT density and XC potential, especially for MGGA.
  - Automatically apply SCF initial guess from existing wavefunction.
  - Improve the first order derivatives of density fitting J/K matrices for non-hermitian density matrices.
  - Improve TDDFT diagonalization numerical stability.
  - Remove redundant integral computation for SR-only (such as HSE) and LR-only (such as wb97) RSH functionals
* Fixes
  - ASE interfaces regarding to the API changes in ASE v3.11.0
  - Missing conj() for t2 amps in GCCSD and UCCSD routines
  - UCCSD damping
  - Fix biased implementation for the becke radi method.
  - Fix DFT define_xc_ interface and examples.
  - Fix SR-ERI integral screening estimator.
  - Fix CCSD two-particle density matrix for complex orbitals.
  - Take cell.rcut into account when generating becke grids for low-dimensional systems.


PySCF 2.7.0 (2024-09-23)
------------------------
* Added
  - Superposition of Atomic Potentials (SAP) initial guess for SCF methods.
  - Supports pickle serialization for all methods.
  - ADC 1-particle density matrix and dipole moment.
  - Spin-separated 3-RDMs.
  - Traceless quadrupole moment for SCF methods.
  - Supports for fractional coordinates in Cell.
  - Population analysis for KSCF.
  - A, B matrices for k-point TDRKS.
  - AutoAux scheme for generating auxiliary basis sets.
* Improved
  - Automatic cleanup for HDF5 temporary files.
  - Saves CI coefficients for SA-CASSCF to chkfile.
  - UHF/UKS initial guess with better spin-symmetry breaking code.
  - New attribute .cycles in SCF methods and CC methods to save iteration counts.
  - FFT performance.
  - CPHF convergence in nuclear hessian.
  - Eigenvalue solver for linear response theory.
  - Enhance TDDFT code with symmetry adaptation in diagonalization.
  - More efficient PBC-CDERI loading.
* Fixes
  - The missing atomic radius parameters for the Treutler-Ahlrichs scheme in DFT grids
  - Symmetry adapted GHF with complex orbitals.
  - Complex-valued FCI matvec operation.
  - Bug in Smearing-RHF for odd number of electrons and disable Smearing-ROHF.
  - MP2 FNO bug when pct_occ=1 .
  - DHF dipole moment.
  - Bug in PBC ECP integral.
  - Bug in parser for spin-orbit ECPs.
  - Wrong transition dipoles of triplet TDDFT states.
  - GHF-X2C dipole moment.
  - FCI symmetry validation code for cylindrical symmetry.
  - Missing complex conjugation for complex orbitals in SymAdaptedGHF.
  - Custom UHF objects using the Hamiltonian in FCIDUMP.


PySCF 2.6.2 (2024-06-19)
------------------------
* Fixes
  - Compatibility issues for NumPy 2.0 release.


PySCF 2.6.1 (2024-06-17)
------------------------
* Improved
  - Allow for custom options for opening h5py file.
  - Linear dependency threshold for density fitting auxiliary basis.
* Fixes
  - Compatibility issues due to NumPy 2.0 release.


PySCF 2.6.0 (2024-06-01)
------------------------
* Added
  - SMD and PCM solvent model
  - Nuclear Hessian for SMD and PCM solvent models
* Improved
  - DFT-D3 and DFT-D4 interfaces. Supporting assigning the acronym such as
    WB97M-D3BJ, WB97M-D4 to the xc attribute.
  - Optimized density fitting performance.
  - Memory usage for RPA.
  - FCI coefficients transformation for more than 64 orbitals.
  - Multi-grid DFT performance greatly optimized.
* Fixes
  - CASCI/CASSCF calculations when mixing C1 symmetry and symmetry=False .
  - "atom" initial guess for ECP with super-heavy atoms.
  - Complex conjugation issues in single k-point JK-build in PBC DF.
  - CCSD(T) for complex orbitals.
  - Dipole moment in SFX2C.
  - High-order XC derivatives.
  - Integer overflow in FCI large address.
  - Multi-collinear XC higher order derivatives.
  - Smearing with predefined chemical potential.
  - Fix frozen attribute for MP2 density matrices.


PySCF 2.5.0 (2024-02-03)
------------------------
* 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.


PySCF 2.4.0 (2023-10-16)
------------------------
* 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.
  - Coding styles and deprecated warnings from numpy.


PySCF 2.3.0 (2023-07-04)
------------------------
* 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 correspond to the original definition
  - 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


PySCF 2.2.1 (2023-03-29)
------------------------
* 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


PySCF 2.2.0 (2023-03-09)
------------------------
* 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


PySCF 2.1.1 (2022-09-21)
------------------------
* 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


PySCF 2.1.0 (2022-09-01)
------------------------
* Added
  - k-point symmetry for mean-field methods and MP2
  - UCASSCF work with state_average
  - make_rdm12s for MCSCF state_average
  - Staggered mesh method for k-point restricted periodic MP2 energy
  - PBC-X2C1E DFT methods in spin-orbital basis
  - Adds make_rdm2 to RHF and UHF
  - Auto-generate frozen-core orbitals
  - Atomic chemical core configuration
  - Various MGGA functionalities (Gradients, Hessian, TDDFT, etc.)
  - Mcfun (multi-collinear functional) and relevant GKS, DKS, X2C-DFT, TDDFT methods for molecules
  - Supports to aarch64 architecture
  - Atomic spherically averaged DFT and add HFS ground-state configurations
  - RPA, URPA
  - UCCSD with density fitting
  - X2C for GHF/GKS on spin-orbital basis (make identical to X2C-SCF with j-adapted basis)
  - Gamma-point periodic EA/IP-ADC
  - K-point periodic EA/IP-ADC
  - CVS-IP-ADC
* Improved
  - DFT numerical integral module with better integral screening
  - Aligns E(HF) of KRCCSD with other CCSD classes, and CISD, MP2 classes
  - Adjustable screening value for eval_ao function
  - MCSCF convergence for small systems
  - Renormalized perturbative triples correction in CCSD
  - Optimises UCCSD 1DM
  - Linear dependency handled for IAOs
  - vhf prescreeening efficiency
  - Lattice sum ranges in PBC AO-value evaluation
  - Various cutoffs in PBC integrals for exceptional cells
  - Handles 1e system for KS methods
  - Try to use original axes when creating Mole object if pointgroup is inputed
  - More symmetry information of MCSCF active space dumped
  - SA-CASSCF nuc grad API reform
  - Upgrade cint library to v5
  - Accelerating SGX module
  - rsdf, gdf, aft, mdf, ft_ao, rsjk modules refactored and their performance are optimized
  - The return status of HF statbility checks
  - GDF 3-index integral tensor loader to support tensor sliced from disk
* Fixed
  - Dynamic level shift for UHF
  - gamma-point TDDFT by adding response fn
  - Initial guess issue for uhf custom Hamiltonian
  - Projecting the dm to a larger basis set in PBC systems using from_chk() and init_guess
  - Ensure deterministic result from pyscf.lib.einsum
  - Symmetry detection bugs and C2v orientation for planar molecules
  - State-average CASSCF 1RDM for orbital canonicalization
  - wfnsym for state_average CASSCF
  - Concatenating two Molecule objects with ecp
  - cisd.tn_addrs_signs for impossible excitations
  - KMP2 takes KHF with precomputed GDF integrals
  - Huckel guess with mol.cart=True
  - UCCSD 2RDM without frozen


PySCF 2.0.0 (2021-11-01)
------------------------
* Added
  - Basis selector '@' to load basis from a file
  - Native version of DF-MP2 for RHF and UHF references
  - Cholesky orbitals as the initial guess for iterative orbital localization.
  - FNOCCSD
  - SCS-DF-MP2
  - Relaxed RHF-DF-MP2 density
  - int1e_grids function to compute Coulomb integrals for a list of grids
  - GDF-KMP2
  - Custom Hamiltonian for UHF
  - Natural Orbitals for DFCASCI and DFCASSCF with approximate CI solvers
  - slow and fast QCISD and QCISD(T) for restricted refs
* Improved
  - Pacakge layout, static checks, and code releasement pipeline.
    Certain features were removed from core modules, including: cornell_shci,
    dftd3, dmrgscf, doci, fciqmcscf, icmpspt, mbd, Molpro2Pyscf, mpicc, nao,
    semiempirical, shciscf, tblis, prop/efg, prop/esr, prop/freq, prop/gtensor,
    prop/hfc, prop/magnetizability, prop/nmr, prop/nsr, prop/polarizability,
    prop/rotational_gtensor, prop/ssc, prop/zfs
  - Compatibility improvements for Python 3.6 and newer
  - Compatibility improvements for h5py 3.0 and newer
  - Online documentation (https://pyscf.org/user.html)
  - Upgrade Libxc to 5.1.7
  - FCIDUMP interface to include ECP scalar contribution
  - DMRG interface
  - Ghost atoms in IAO/IBO
  - PBC-GDF auxiliary basis treatment with nonzero drop_eta
  - pivoted Cholesky factorization
  - Support high angular momentum in GTO basis (up to l=15)
  - Make Exact FF GW root finding more robust, reduce eta
  - cubegen for arbitrary unit cells
  - Range of lattice sum for non-orthogonal lattice
  - krkspu
  - Number of calls to gc.collect()
* Fixed
  - PBC-GDF and PBC-MDF when computing RSH functionals
  - The edge case for zero beta electrons in SCF
  - Atomic initial guess if multiple elements have ecp
  - The ordering of unique points in kpts.unique function
  - J matrix of AFTDF
  - kuccsd rdm1
  - GDF int2c2e integrals for non-symmetric range of lattice sum
  - Complex-valued symm. adapted basis
  - NEVPT2 for multistate CI wave function


PySCF 1.7.6 (2021-03-28)
------------------------
* Added
  - KMP2 2-particle density matrix
  - PBC J, K matrices module rsjk (RangeSeparationJKBuilder)
  - ADC (RADC, UADC, DFADC)
  - Eigenvector analyzer for IP and EA, RADC and UADC
  - Analytical nuclear gradients for state-average CASSCF
  - Support SO3 symmetry
  - ECP-SOC for GHF/GKS
  - density fitting GMP2
  - G0W0 approximations (analytic continuation, contour deformation)
  - Auxiliary second-order Green's function perturbation theory (AGF2)
  - Smearing for molecules
  - Visscher small component correction approximation for DHF
  - DFT+U
* Improved
  - Threading safety in Mole temporary context
  - Basis parser to support arithmetic expressions in basis data
  - dmrgci interface refactored
  - MP2 gradients performance
  - Interface of polariazable embedding with integral batching
  - Electron-phonon Hamiltonian module refactored
  - Remove memorization of Ewald parameters.
  - molden dumper refactored
* Fixed
  - stack overflow in ecp integral code
  - SCAN functional crashing problem
  - Ghost atoms for IAOs/IBOs
  - Fix fractional occupations for case of zero beta electrons
  - mcscf project_init_guess
  - Symmetry verification bug when deducting subgroup
  - Mole.set_geom_ bug
  - GDF with non-zero drop_eta (for diffused auxiliary basis)
  - Paddings in KMP2 when remove_linear_dep_ is applied
  - SC-NEVPT2 Sijr Srsi



PySCF 1.7.5 (2020-9-27)
-----------------------
* Added
  - Upgrade cint library to v4
  - Upgrade xcfun library to v2.1.0
  - Kramers' restricted Dirac-Hartree-Fock, X2C, DHF-SOSCF
  - Heavy elements basis in MINAO
  - Coulomb integrals of short range part for attenuated Coulomb
  - Polarizability and hyperpolarizability under PBC
* Improved
  - Support pseudo potential Atomic HF
  - Atomic HF for 1-electron system
  - Check basis angular momentum in mol.intor (l < 7)
  - FCIDUMP wrapper fcidump.py
* Fixed
  - Bugs in Mole.fromstring
  - Buffer size bug in DHF JK builder for very small systems
  - Fix pbc-eom-eaccsd_star bug
  - Bugs in integral screening for very tight direct_scf_tol


PySCF 1.7.4 (2020-8-2)
----------------------
* Added
  - FCIDUMP reader to load FCIDUMP and generate custom system.
  - Natural orbitals occupations to mc.mo_occ
  - Supporting UHF orbitals in FCI factory function
* Improved
  - Linear dependency treatment for basis uncontraction
* Fixed
  - ECP gradients bug when the system contains two or more ecp atoms
  - CHGCAR writer
  - Basis parser for basis in Gaussian 94 format


PySCF 1.7.3 (2020-6-10)
-----------------------
* Added
  - CcECP basis
  - Spin 1RDM for shci
  - PM localization for charge populations based on Becke partition
* Improved
  - Compatibility of get_jk methods between mcscf class and scf class
  - CPPE interface
  - Interface between IAO and PM
* Fixed
  - an CCSD integral bug introduced in 1.7.1
  - Td as its subgroup C2v
  - Fix an error when calculating grad of dft method with "HF" as xc



PySCF 1.7.2 (2020-5-13)
-----------------------
* Added
  - Electron-phonon Hamiltonian under PBC (pbc.eph)
  - State-average CASSCF example
  - Spin density analysis to uhf.analyze()
  - Passing point group and wfnsym to Dice
  - Analytical nuclear gradients for PBC SCF methods (based FFTDF)
  - Geometry optimizer and Gradients scanner for pbc
  - ccECPs and corresponding basis sets
  - Interacting hybrid method i-CCSD/MP2
  - Allow FNOs to be specified by number of active virtuals
  - Enable frozen natural orbital CC
  - Partial Cholesky orthogonalization
  - Use requested initial guess in DHF
* Improved
  - libxc5 compatibility
  - Redundant def2-*-jkfit basis sets were replaced by the def2-universal-jkfit basis
  - FCIDUMP reader
  - Treatment of breaksym in UHF init_guess function
  - literature references and DOIs
  - Ensure active orbitals are not changed during MCSCF canonicalization
  - Improve linear dependency treatment in projection function in scf/addons.py
  - Use customized get_xmat method for x2c if applicable
* Fixed
  - Integral bug in magnetizability
  - Integer overflow in multigrid
  - pbc.mdf h5 file initialization
  - density fitting auxiliary basis for cc-pV*Z
  - Handle basis and pp for ghost atoms in pbc initialization
  - ecp treatments for ghost atoms
  - FCI wfnsym initial guess
  - SCF initial guess for super-heavy elements
  - Initial guess "atom" due to missing basis
  - Bugs of prefix ghost
  - Handle duplicated primitives in GAMESS WFN writer


PySCF 1.7.1 (2020-2-29)
-----------------------
* Added
  - Equilibrium solvation for TDDFT
  - ddcosmo TDDFT gradients to support TDDFT geometry optimization with solvent
  - Polarizable embedding solvent model
  - Non-canonical MP2
  - Algebraic diagrammatic construction method
* Improved
  - Atomic configuration in SCF initial guess
  - IBO valence space configurations
  - For icmpspt restart option and default settings
  - TBLIS interface and compilation configurations
  - DFT-KS initialization factory functions
  - reset methods in many modules for scanner mode
  - HF/KS conversion functions
  - APIs for HF/KS response functions (used by TDDFT and other methods)
  - transform_ci function to allow projection between FCI wavefunction in
    different sizes
  - The fractional occupancy atomic HF method in SCF initial guess
  - Performance of non-local XC functional
  - FCI Performance
  - stability of linear equation solver in dynamic polarizability
  - cubegen for PBC systems
* Bugfix
  - Contributions of MM point charges in icmpspt energy
  - ROHF and UHF orbital occupancy for negative mol.spin
  - Four-component Dirac HF EFG tensor
  - Avoid twice initialization in modules GDF, SGX etc.
  - nuclear repulsion energy for single atom case
  - MINDO gradients unit (from Hartree/Angstrom to Hartree/Bohr)
  - Data prefetching bug in CCSD
  - Total energy of CCSD and CISD with non-canonical HF reference


PySCF 1.7.0 (2020-1-1)
----------------------
* Added
  - k-CCSD density matrix
  - k-CCSD(T) with core frozen
  - sgX method (a pseudo-spectral method like COSX)
  - pre_kernel and post_kernel hooks in SCF driver
  - Left eigenvectors of IP/EA-CCSD for molecular code
  - EOM-IP/EA-KCCSD, EOM-IP/EA-KRCCSD
  - Methods EOM-IP/EA-KCCSD(T) T*(a), EOM-IP/EA-KRCCSD(T) T*(a)
  - kEOM-IP/EA-CCSD*
  - KUMP2
  - KCCSD function spatial2spin that transforms amplitudes in spatial orbital
    representation to that in spin-orbital representation
  - DOCI solver, DOCI-CASCI, and DOCI-CASSCf
  - Support of RSH functionals in methods DF and sgX
  - Add RSH functionals for all PBC DFT methods
  - Semi-empirical method MINDO/3
  - Analytical nuclear gradients with density-fitting
  - Analytical nuclear hessian with density-fitting
  - Thermo-chemistry and frequency analysis
  - Huckel HF/KS initial guess
  - QM/MM with implicit solvent
  - Spin-Orbit ECP integrals
  - Geometry optimization for state-average MCSCF method
  - cube file parser
  - Orbital localization methods VVO and LIVVO
* Improved
  - Optimized regular get_j and density-fitting get_j
  - Faster k-CCSD(T)
  - Davidson diagonalization for multi-roots
  - memory usage in CCSD
  - Molecular orientation does not need to be changed when symmetry is enabled
  - Performance of density fitting initialization
  - Performance of JK-build function
  - Using direct_spin1 as the default FCI solver
  - Performance of SOSCF method (by using the direct-SCF technique)
  - Performance of semi-incore AO-MO integral transformation
* Bugfix
  - Carbon ANO data
  - Initial guess for EOM-KCCSD
  - state-average CASSCF analytical nuclear gradients
  - ddCOSMO self-consistency (as fast solvent) for post-SCF methods
  - range-separation parameter omega customization in RSH functionals


PySCF 1.6.6 (2020-1-1)
----------------------
* Improved
  - Sanity check for Wigner-Seitz cell exchange kernel
  - The linear dependency treatment for X2C uncontracted basis
  - Energy cutoff estimation for non-orthogonal lattice
  - Tolerance in geometry when detecting point group symmetry
* Fixed
  - TDDFT symmetry representation
  - cube file when containing ECP


PySCF 1.6.5 (2019-11-17)
------------------------
* Added
  - spin_square method for UCCSD
* Improved
  - Handling ".xc = None" (run DFT without exchange)
* Fixed
  - Unit conversion bug between eV and wavenumber in TDDFT
  - KGHF orbital gradients
  - Analytical gradients for implicit solvent model in geometry optimization


PySCF 1.6.4 (2019-09-14)
------------------------
* Added
  - aug-cc-pwCV*Z basis
* Improved
  - Memory footprint of FCI module
  - Mole.spin initialization. A guess can be made for spin multiplicity based on
    neutral system.
* Fixed
  - PBC SCF orbital canonicalization
  - Missed complex conjugation in HF/KS modules
  - SHCI runtime directory
  - Normalization issue for Cartesian basis in Molden output
  - cc-pwCV5Z basis


PySCF 1.6.3 (2019-07-28)
------------------------
* Added
  - cube customization for cubegen
  - Integral prescreening for RSH functional when evaluating K matrix
* Improved
  - Performance of exchange integrals in RSH functionals
* Fixed
  - handle xc = '' in eval_ao
  - cube shape in cubegen
  - Basis parser when parsing last elements in some basis set
  - ROHF-SOSCF for diatomic molecules


PySCF 1.6.2 (2019-6-17)
-----------------------
* Added
  - Slow version of KTDSCF and KGW methods for molecular systems
  - Slow version of TDSCF and GW methods for PBC systems
  - The support of various dtype (int, complex etc.) in numpy_helper functions
  - Point group symmetry conservation in geometry optimization
* Improved
  - DFHF class structure and method hooks
  - Sanity checks when saving and loading FCIDUMP file
  - Integral performance for solvent model
  - Integral performance for QM/MM interface
  - GCC 9 compatibility
* Bugfix
  - Cartesian GTOs was not handled in RSH integrals
  - geometric_solver for latest geomeTRIC release
  - Initial guess of orbital localization solver
  - MCSCF analyze function for state-averaged calculations
  - The zero-norm bug in the non-hermitian matrix diagonalization function when
    solving the complex eigenvectors for real eigenvalues.
  - IOError when reading initial guess from chkfile in SCF scanner function


PySCF 1.6.1 (2019-03-15)
------------------------
* Added
  - k-point orbitals to gamma-point orbitals transformation function k2gamma
  - Wigner D-matrix and d-matrix
  - The interface geometric_solver to geometry optimization library geomeTRIC
  - k-CCSD(T) for PBC k-point sampled systems
  - AO basis truncation shortcut "@?s?p?d"
  - Function in basis parser to restore general basis contraction from NWChem
    optimized format
  - inertia_moment function in Mole object
  - keyword resolution in CHGCAR writer
  - IAO for each k-point in PBC systems
* Improved
  - Geometry optimization module (GeometryOptimizer class, output format etc.)
  - SCF Gradients class. A hook "extra_force" was added.
  - MRLCC2 interface
  - Import gradients, properties, solvent, and all post-SCF/extended methods in SCF class
  - DFT-D3 interface
  - Pople basis parser (supporting e.g. 6311++g(2d,p)).
  - Normalizing SCF initial guess in PBC (to the right number of electrons/cell)
  - mesh estimation for inf-vacuum
  - Tuned threshold in point group symmetry detection functions
  - SCF summary in the output message
* Bugfix
  - Solvent object initialization in SCF scanner function
  - GHF get_jk function
  - QM/MM object initialization in SCF scanner function
  - Missing virtual orbitals in MCSCF project_init_guess function
  - MINAO basis data
  - Analytical Fourier transform zero elements when basis functions do not overlap
  - make_rdm1 function in state_average mcscf wrapper


PySCF 1.6 (2018-12-31)
----------------------
* Added
  - DFT-D3 interface
  - semi_incore ao2mo transformation
* Improved
  - Linear dependency threshold of qr decomposition in davidson solver
  - Optimized KUCCSD, EOM-KUCCSD performance
* Bugfix
  - hasattr issue for attributes with @property
  - DDCOSMO wrapper and kernel function
  - Num eletrons bug in PBC smearing function for custom systems
  - return value of NPTaggedArray ufunc (returning np array now)
  - PBC density fitting dimension error caused by numerical noise when handling linear dependency
  - Parsers for molpro basis and gaussian basis
  - Selected-CI returned data type


PySCF 1.6 beta (2018-11-26)
---------------------------
* Added
  - PBC k-point SCF stability analysis
  - PBC KUCCSD
  - PBC EOM-IP/EA-KRCCSD
  - PBC EOM-IP/EA-KUCCSD
  - Non-relativistic static and dynamic polarizability and hyper-polarizability tensor
* Improved
  - The treatment of HF exchange in PBC system when calling PBC MP2, CISD, CCSD code
  - Convergence performance of KCCSD iterations for low-dimension systems
* Bugfix
  - Complex density in pbc.get_j function


PySCF 1.6 alpha (2018-08-15)
----------------------------
* Added
  - X2C-UKS (LDA functional only)
  - PBC gamma point ROHF/ROKS and GKS
  - PBC KROHF/KROKS and KGKS for k-point sampling
  - DFT Coulomb and XC integrals with multigrid
  - Periodic UCCSD with k-point sampling
  - perturbative DMRG method
  - Interface to Cornell SHCI
  - PBC dipole memont and Makov-Payne correction
  - Overlap of two CISD wavefunctions
  - EFG and Mossbauer spectroscopy of crystal and molecule
  - Molecular magnetizability for HF and DFT
  - ddCOSMO and ddPCM for MCSCF, MP, CI and CC methods
* Improved
  - numint performance (eval_rho, eval_mat)
  - Energy cutoff estimation
  - CCSD convergency for 2D-PBC AFTDF, GDF and MDF methods
  - Integral transformation performance in GW


PySCF 1.5.5 (2018-12-31)
------------------------
* Improved
  - Fix symmetrization for k-point density in pbc.dft.numint.
  - Molden parser to handle UHF orbitals
* Bugfix
  - Get_fermi in KHF and KUHF
  - Execute call in dmrgci
  - Directories and paths in dmrgci
  - Read of 3-pdm and 4-pdm produced by block-1.5
  - Initialization wrapper in pbc.scf.__init__
  - Complex density in pbc.get_j function
  - Initial guess of KROHF method
  - PBC get_jk interface when calling molecular MCSCF with pbc scf object
  - keyword argument with_df of pbc.dft density_fit wrapper


PySCF 1.5.4 (2018-11-16)
------------------------
* Improved
  - Add support for GTH pseudopotentials beyond d electrons
  - Data structure of TDDFT response amplitudes (X, Y vectors): X[nvir,nocc] -> X[nocc,nvir]
* Bugfix
  - OpenMP race condition in FCI solver
  - Undefined HDF5 dataset in PBC MDF initialization
  - TD-KRHF vind function
  - SCF hessian
  - interface between DMRG-CI and DMRG-NEVPT2. Making DMRG-NEVPT2 read Block
    code settings in DMRG-CI.
  - Dimension error in pbc.fftdf.get_jk for KUHF density matrix
  - pbc.mpicc for keyword frozen
  - Periodic pseudopotential calculations with ghost atoms


PySCF 1.5.3 (2018-09-06)
------------------------
* Bugfix
  - get_jk prescreen for non-hermitian density matrices.
  - Inaccurate estimation of memory usage in ccsd rdm.
  - Frozen orbital EA-EOM-KRCCSD
  - IOError due to 4GB chunk size limit in HDF5 library


PySCF 1.5.2 (2018-08-15)
------------------------
* Improved
  - IO performance of pbc.GDF initialization
  - Default linear dependence treatment in GDF to improve accuracy
* Bugfix
  - Selected-ci 2-particle density matrices for two electron systems


PySCF 1.5.1 (2018-07-01)
------------------------
* Improved
  - The memory usage for a large number of MM particles (issue #193)
* Bugfix
  - Frozen orbitals in MCSCF canonicalization
  - Dimension error when initializing DF-CCSD integral tensor
  - EOM-EE-UCCSD initial guess and intermediates (issue #199)
  - mpi ip/eaccsd w/ frozen orbitals
  - the tdscf.get_nto function when mol.symmetry is enabled (issue #196)
  - the interface between QMMM wrapper and the gradients of post-HF methods


PySCF 1.5 (2018-06-08)
----------------------
* Added
  - Fake PySCF method adapter for arbitrary energy/gradients function in
    berny_solver wrapper
  - Function to restore DIIS object from DIIS file
  - Restart function to restore CCSD calculations
* Improved
  - CASSCF optimization step size
  - State-averaged CASSCF output message
  - RCCSD(T) and UCCSD(T) performance
  - Reduced DIIS memory footprint
  - Frozen orbitals for KRCCSD
  - PBC-TDDFT eigenvalue filter to keeps more eigenvalues which has small
    imaginary part
  - FCI convergence tolerance
  - Conversion between KRHF, KUHF, and KGHF
  - In the SOSCF solver, the diagonalization code to handle singularity in Hessian
  - In the Scanner function, to support an input of geometry (string or list)
  - SCF convergence hook
  - Density_fit hooks in mp2, cisd, and ccsd modules
  - Warning for gapless system in ccsd
  - Energy cutoff for PBC GDF method.
  - XC functional parser to support '-' in XC name and XC functional
    abbreviations (SVWN, BLYP, PBE, M05, etc.)
  - Orbital frozen in core and virtual space for KMP2 and KCCSD modules
* Bugfix
  - The ghost atom is now treated as a regular atom in berny_solver wrapper.
  - QM/MM nuclear gradients
  - Updating 6-31+G* basis which is now equivalent to the EMSL published basis
  - Symmetry detection code to discover D2d, D4d, D6d group
  - xcfun O3LYP functional which is now the same to libxc definition (but
    different to the equation in the original paper)
  - xcfun cam-b3lyp functional interface
  - HCI wrapper to handle the system without beta electrons
  - Dimension error for spinor integrals in general JK-build function
  - The orbital ordering of the returned orbitals of the UHF stability analysis
  - Filling up the upper triangular part for symmetry Hamiltonian in fcidump.read
  - The attributes kpts and kpt of PBC SCF class when SCF data are loaded from
    chkfile
  - Nuclear Hessian in ECP and all-electron mixed systems
  - Natural orbitals of state-averaged CASSCF


PySCF 1.5 beta (2018-04-15)
---------------------------
* Added
  - ddCOSMO analytical nuclear gradients
  - TDA and TDDFT analytical nuclear gradients for UHF and UKS
  - CISD/GCISD/UCISD 1-particle transition density matrix
* Improved
  - Memory usage of KRHF-KCCSD and IP/EA-EOM-KCCSD
* Bugfix
  - Fock matrix of ddCOSMO and ddPCM method.


PySCF 1.5 alpha (2018-03-21)
----------------------------
* Added
  - ddCOSMO solvent model
  - VV10 NLC functional for molecule
  - range-separated hybrid features for RKS and UKS, including
    > Analytical nuclear gradients
    > Second order SCF
    > Hessian and frequency
    > TDDFT
    > TDDFT gradients
    > NMR
  - IAO and IBO for molecular and PBC systems
  - UHF analytical nuclear Hessian
  - UKS analytical nuclear Hessian
  - FFT for low-dimension (2D) PBC systems
  - Generalized CCSD (GCCSD)
  - Generalized CCSD lambda solver
  - Generalized Hartree-Fock with PBC
  - PBC GCCSD and RCCSD with k-point sampling
  - PBC GCCSD(T) and RCCSD(T) with k-point sampling
  - RCCSD(T) and UCCSD(T) for non-canonical HF orbitals
  - RCISD and UCISD analytical nuclear gradients
  - RCISD, UCISD analytical nuclear gradients for excited states
  - RMP2 and UMP2 analytical nuclear gradients
  - UCCSD analytical nuclear gradients
  - Frozen orbitals in MP2, CISD, CCSD, CCSD(T) nuclear gradients
  - SF-X2C-1E analytical nuclear gradients
  - SF-X2C-1E analytical nuclear hessian
  - Analytical nuclear gradients and hessian for ECP integrals
  - GIAO-ECP integrals for NMR shielding
  - Interface to pyWannier90
  - Restricted MP2 with k-point sampling
  - RCCSD(T), UCCSD(T) and GCCSD(T) 1-particle and 2-particle density matrices
  - RCCSD(T), UCCSD(T) analytical nuclear gradients
  - CASCI/CASSCF analytical nuclear gradients
  - CASCI analytical nuclear gradients for excited states
  - Cartesian GTO (6d 10f) basis in PBC calculations
  - Natural transition orbital analysis
  - direct-RPA (no exchange, aka TDH)
  - direct-TDA (TDA without exchange)
  - Function to set OpenMP threads
* Improved
  - Independent OpenMP threads in FCI solver
  - Supported even number of grids in pbc calculations
  - Performance of UCCSD lambda solver
  - The function to get SCF initial guess from the chkfile of the molecule with
    different geometry
  - The mcscf natural orbitals in the state-average calculation
  - Performance of ECP integrals
  - Prescreening for PBC 3-center integrals
  - Performance and memory efficiency of G0W0
  - KMP2 memory efficiency
  - Efficiency to evaluate the value of periodic AO on grids
  - libxc parser to support the customized Range-separated XC functionals


PySCF 1.4.7 (2018-04-15)
------------------------
* Bugfix
  - Outcore ao2mo transform when basis functions are cartesian Gaussians
  - Fix errors in dmrg-nevpt interface, which overwrite nevpt configure files by
    variational dmrg configure files.
  - The order of elements of a list that are loaded by chkfile.load


PySCF 1.4.6 (2018-04-02)
------------------------
* Added
  dip_moment method for ROHF class


PySCF 1.4.5 (2018-03-23)
------------------------
* Bugfix
  - Numerical grids not converged in ECP integrals
  - Python3 compatibility in shci module


PySCF 1.4.4 (2018-03-20)
------------------------
* Improved
  - Non-Hermitian matrix diagonalization
  - Symmetric grids in cubegen
  - FCI initial guess when the system has Dooh or Doov symmetry
  - Using stable sort when sorting orbital energies
  - Attribute "e_tot" in the MP2 methods to access the total energy
* Bugfix
  - meta-GGA density in dft.numint.eval_rho2
  - intor parser in ao2mo module
  - ecp parser if ecp data not found
  - 1-electron system for UCCSD
  - Python-3 compatibility for dmrgscf module
  - Handling the errors which were raised in the background threads
  - UHF/ROHF density matrices in nao localization method


PySCF 1.4.3 (2018-01-17)
------------------------
* Improved
  - Assert convergence in geometry optimization
  - Initial guess in SCF PES scanning
  - Memory usage for generating Becke-grids in DFT
* Bugfix
  - XC parser to support the scaled compound functional
  - In the second order SCF algorithm, removing level_shift
  - k-point RCCSD for non-canonical HF reference
  - ECP integrals


PySCF 1.4.2 (2017-12-06)
------------------------
* Added
  - Frank Jensen, Polarization consistent basis sets
* Improved
  - Memory usage of pbc KHF calculation when HF exchange is computed with FFTDF
* Bugfix
  - pyberny interface
  - PBC GDF initialization for hybrid functional
  - guess of wfn symmetry for given fci wfn
  - Entropy of Gaussian smearing


PySCF 1.4.1 (2017-11-12)
------------------------
* Bugfix
  - meta-GGA functional detection code in XC parser
  - Orbital symmetry label in mcscf initial guess projection
  - Eigenvalue ordering for Davidson eigen solver
  - Madelung constant of non-orthogonal lattice
  - Convergence of Madelung constant for huge number of k-points samples
  - basis parser for pople-type basis
  - RCCSD when running large number of virtual orbitals on small memory machine

PySCF 1.4 (2017-10-05)
----------------------
* Improved
  - Kinetic energy cutoff estimation
  - Density fitting default auxiliary basis
  - Memory usage for FFTDF module
  - libxc interface
* Bugfix
  - KUHF dimension error in smearing function
  - SCF results inconsistency in chkfile and SOSCF solver
  - OMP stack overflow in GTO basis evaluator
  - Default grids in DFT gen_grid function for system with ECP/PP
  - mol.intor function to generate STG and YP integrals in 8-fold symmetry
  - TDDFT analytical gradients
  - DMRG-CI runtime scratch path
  - PBC GDF integrals for auxiliary basis with g functions
  - post-HF initialization function when mean-field object is DF-SOSCF method
  - Single orbital localization
  - Race condition in MP2 IO


PySCF 1.4 beta (2017-08-22)
---------------------------
* Added
  - Generalized Hartree-Fock (GHF)
  - Second order SCF solver for GHF
  - non-relativistic UHF, UKS g-tensor (with various SOC approximations)
  - non-relativistic UHF, UKS hyperfine coupling
  - SHCI interface to Dice program
  - spin-orbital CISD
  - UCISD and UCISD 1- and 2-RDM
  - Restricted CC2 method
  - Density-fitting CCSD
  - Heat-bath selected CI (HCI) spin-orbital 1- and 2-RDM
  - "scanner" function for HF, DFT and CCSD to simplify energy or
    gradients scanning for systems of different geometry.
  - Interface to pyberny geometry optimizer (geometry optimization for
    RHF, RKS and RCCSD are supported).
* Improved
  - U-CCSD(T) performance
  - Package structure (following "The Hitchhiker's Guide to Python")
  - ECP basis localization in Mulliken pop analysis
  - Changing the CASCI/CASSCF default FCI solver (the default solver will not
    use spin symmetry for singlet state)
  - Supporting remove_linear_dep function to handle basis linear dependence in
    k-point SCF
  - cell.rcut estimation for better integral accuracy
  - Convergence rates of PM localization
  - MP2 and RCISD integral transformation performance
  - Disk usage of CCSD-DIIS
  - Input basis parser to support union basis set (eg mol.basis=(bas1,bas2))
  - SCF initial guess for systems with pseudopotential (or ECP)
  - SCF initial guess for low-dimension PBC systems
* Bugfix
  - wfnsym of FCI solver for Dooh symmetry
  - In CIAH newton solver, the special treatment of negative hessian has
    been revised.
  - import lock which freezes threads for functions running in background


PySCF 1.4 alpha (2017-07-24)
----------------------------
* Added
  - General function to evaluate Spinor GTO on real space grids
  - Dirac-Kohn-Sham (LDA functional)
  - EDIIS and ADIIS
  - Periodic CCSD with k-point sampling
  - Periodic EOM-IP-CCSD and EOM-EA-CCSD for single k-point calculation
  - spin-square value (per unit cell) of KUHF calculation
  - Update interface to fciqmc for standalone executing
  - Routines in fciqmc to read in the spinned one and two RDMs
  - Heat-Bath CI
  - Functions in dmrgci interface to access 3-pdm and 4-pdm
  - Function get_fermi
  - UCCSD lambda equation and 1,2-particle density matrix
  - SCF wfn stability analysis
  - Many-Body van der Waals Interactions (MBD)
  - Second order SCF solver for periodic HF and DFT
  - TDDFT for periodic k-point HF and DFT
  - U-TDHF and U-TDDFT for molecular and crystal systems
  - Many-body dispersion
  - MP2-F12 and F12 basis and F12 RI basis
  - Cartesian GTO (6d 10f) basis in molecular calculations
  - CP2K's HF pseudopotential data
  - Frozen core MP2
  - Molecular electrostatic potential (MEP)
  - CPHF and UCPHF solver
  - Non-relativistic RHF, UHF 4-component UHF spin-spin coupling
  - non-relativistic UHF, 4-component UHF g-tensor (in testing)
  - non-relativistic UHF, 4-component UHF hyperfine coupling (in testing)
  - non-relativistic UHF zero-field splitting (in testing)
* Improved
  - Performance of PBC-Gaussian function evaluator
  - Performance of analytical Fourier transformation for AO product
  - Performance of PBC 3-center integrals
  - Performance of PBC PP local-part integrals
  - Numerical stability associated to OpenMP reduce function
  - Performance of FCI 2-electron contraction function
  - Basis parser for Pople style basis sets
  - Arbitrary problem size in FCI solver
  - Symmetry labels in orbital coefficients
  - Disk usage of integral transformation in MP2
  - Performance of J/K contractions in molecular density fitting code
  - Input geometry parser for ghost atoms
* Bugfix
  - PBC super cell function.  Atoms was missing on the super cell boundary
  - PBC dft atomic grids for low-dimension systems
  - The missing occ-vir blocks of Fock matrix in UCCSD
  - MGGA integration error
* Removed
  - Dependence to joblib library


PySCF 1.3.5 (2017-08-11)
------------------------
* Bugfix
  - The undefined += operation (numpy issue #5241) in CISD and CCSD methods


PySCF 1.3.4 (2017-08-08)
------------------------
* Improvements
  - Handle ghost atom in HF initial guess.
  - Remove special treatments on CIAH negative hessians which often cause convergence problem
  - Memory usage in CISD
  - Proper treatment of ECP/PP in Mulliken pop analysis
* Bugfix
  - For ROHF reference, CCSD function takes UCCSD method.
  - Handle zero beta electrons in UCCSD.
  - Fix bug in FCI solver when system has Dooh symmetry.
  - Fix bug in KUHF gradients which affects newton SCF convergence.
  - Fix bug in gradients of PM localization which affects convergence.
  - Fix "hcore" initial guess for KHF.
  - Fix bug in Mulliken pop analysis caused by wrong overlap matrix for PBC calculations.


PySCF 1.3.3 (2017-07-05)
------------------------
* Bugfix
  - GIAO contributions to the off diagonal part of NMR shielding tensor.
  - Handle zero core electrons in ECP parser.
  - Handle zero occupied orbitals in CCSD module.
  - Handle 1-electron system in UHF.
  - Fix orbital ordering in SCF canonicalization when point group symmetry is used.
  - Fix the missing fov term in UCCSD intermediates.
  - Fix pbc atomic grids for low dimensional system.
  - Avoid negative hessian in second order SCF solver.
  - Fix bug in fci solver when system has cylinder spatial symmetry
  - Fix eval_rho for GGA functional for non-hermitian density matrix


PySCF 1.3.2 (2017-06-05)
------------------------
* Bugfix
  - CCSD frozen core when using AO-driven algorithm
  - DFT UKS orbital hessian
  - PBC gamma-point UHF exxdiv=ewald correction
  - KUHF get_bands function


PySCF 1.3.1 (2017-05-14)
------------------------
* Bugfix
  - CISD output message for multiple roots
  - UHF hessian function in the second order SCF solver
  - Integer overflow in npdot
  - Module import error in PBC second order SCF solver
  - Update makefile due to the bugfix in libcint library


PySCF 1.3 (2017-04-25)
----------------------
* Improved
  - Treatment of auxiliary basis linear dependence in PBC DF/MDF module
  - Cutoff radius in real space lattice summation for better accuracy
  - PBC get_bands to compute the bands of arbitrary input k-points
  - Ewald sum convergence
  - Atomic grids in PBC DFT calculation
* Bugfix
  - Analytical Fourier transformation for non-orthogonal lattice
  - Spinor integral buffer size when kappa!=0
  - AVAS active space when mol.symmetry is enabled
  - Input parser for Gaussian nuclear model
  - Sorting CISD RDM2 in Chemist's ordering
  - runtimeDir in dmrg interface
  - numpy.exp overflow in PBC smearing function
  - The FFT-based MO integrals in compressed format
  - Input parser to handle unicode
  - UHF spin-square function for complex orbitals
  - Setfault in FCI 4-particle transition density matrix
* Removed
  - The cache of PBC AO value on grids
  - Split-fitting MDF module


PySCF 1.3 beta (2017-02-15)
---------------------------
* Added
  - sf-X2C for PBC Hamiltonian
  - Overlap of two CI wavefunctions over different orbital bases
  - EOM-CCSD for user guess, Koopmans' excitations, etc
  - Approximate EOM-CCSD (MBPT2 ground state and partitioned EOM Hbar)
  - AVAS method for constructing mcscf active space
  - Molpro XML file reader and interface to read Molpro orbitals
  - UCCSD
* Improved
  - EOM-EE-RCCSD and EOM-EE-UCCSD performance
  - memory usage of the non-symmetric Davidson solver in EOM-CCSD


PySCF 1.3 alpha-2 (2017-01-04)
------------------------------
* Added
  - Supports for 1D, 2D PBC systems
* Improved
  - Integral transformation for PBC 2-electron integrals
  - CASSCF state-average interface to handle sub-solvers of different spins
  - Numerical stability for Davidson diagonalization solver
  - Numerical stability of FCI contraction function under multithreading environment
  - FCI 2-electron contraction function with point group symmetry
* Bugfix
  - X2C to use custom basis for X matrix


PySCF 1.3 alpha-1 (2016-12-04)
------------------------------
* Added
  - Quantum chemistry ECP for solid
  - AO-direct RCCSD
  - CI coefficients transformation for one-particle basis rotation
  - CIAH second order SCF solver for PBC KRHF and KUHF methods
  - CISD and CISD 1, 2-particle density matrices
  - Selected-CI and Selected-CI 1, 2-particle density matrices
  - Smearing for PBC mean-field calculation
  - PBC density fitting
* Improved
  - Performance of CCSD(T)
  - Change the default kpts mesh (to always include gamma point)
  - PBC repeated images used by lattice summation


PySCF 1.2.3 (2017-04-24)
------------------------
* Bugfix
  - PBC 2e integrals for wrap-around k-points
  - CI coefficients in GAMESS WFN format
  - Input parser for Gaussian nuclear model
  - Density fitting outcore module for user input auxiliary basis


PySCF 1.2.2 (2017-02-15)
------------------------
* Bugfix
  - GTO normalization in molden file
  - multi-threading dgemm


PySCF 1.2.1 (2017-01-26)
------------------------
* Added
  - transition metal BFD basis
  - script to fix dylib library dependence for Mac
* Bugfix
  - active space 1pdm in mc chkfile if natural orbitals are required
  - dmrg example
  - state-average dmrgci interface
  - analytic GTO-PW integral
  - for population analysis when ecp is presented.
  - for mcscf state-specific function to support ground state as the target state
  - get_coulG round-off bug
  - unit cell size estimation for non-orth crystals
  - lib.norm function for complex vector


PySCF 1.2 (2016-11-07)
----------------------


PySCF 1.2 beta (2016-09-13)
---------------------------
* Added
  - State average CASSCF helper function for mixed spin/spatial-symmetry FCI solvers
  - Example for transition dipole momentum
  - U-CCSD (based on spin-orbital formulation)
  - IP/EA/EE-EOM-CCSD
  - Function to dump CASSCF canonical orbitals in molden format
  - Analytical Fourier transformation for AO and AO product
  - Co-iterative augmented hessian (CIAH) orbital optimizer
  - Optimized einsum function using numpy.tensordot function
  - Burkatzi-Filippi-Dolg pseudo potential
  - FCI solver to support integrals which do not have 8-fold symmetry
  - Dual interface to call pyFFTW or numpy.fft
  - Maximum overlap method (MOM) method for SCF method
* Improved
  - Memory usage for MDF method (molecular and PBC systems)
  - PBC AO value evaluation performance
  - Orbitals space symmetrization
  - CASSCF subspace (core, active, external) symmetrization
  - Created X2C object to hold X2C functions and parameters
  - Boys, Edmiston, Pipek-Mezey Localization with general CIAH optimizer
  - PBC integrals to handle ghost atom in PBC calculation
  - Asynchronized IO to overlap integration and IO for ao2mo integral transformation
  - SCF gradients to eliminate the symmetry forbidden matrix elements
  - Fixing orbital ordering for degenerated SCF orbitals
  - Efficiency of transpose_sum function
  - FCIDUMP output format
* Bugfix
  - CASSCF/QMMM interface for the missing term in nuclear repulsion
  - Screening small density for MGGA functionals
  - Molden interface to handle symmetry broken orbitals
  - MP2 density matrix to include HF DM


PySCF 1.2 alpha (2016-8-5)
--------------------------
* Added
  - MDF (mixed density fitting) method for molecule and PBC 2-election integrals
  - GAMESS WFN wirter
  - Periodic boundary condition (PBC) for gamma point RHF, UHF, RKS, UKS
  - PBC RHF, UHF, RKS, UKS with k-point sampling
  - PBC AO integrals
  - PBC MO integral transformation
  - PBC density fitting
  - IC-MPS-PT2
  - DMET decomposition to generate CASSCF active space
  - FCI electron-phonon coupling solver
  - meta-GGA for ground state DFT


Version 1.1 (2016-6-4):
* Improved
  - "unc-" prefix for uncontracted basis in the input
  - linear dependence problem in mcscf.project_init_guess
* Bugfix
  - CCSD(T) rdm
  - CASCI.analyze for multiple CI roots
  - function to write FCIDUMP when system has symmetry


Version 1.1 beta (2016-4-11):
* Added
  - Orbital hessian for SCF Newton solver
  - (maximum overlap method) for Delta SCF
  - determinant overlap
  - Canonicalization flag for Newton solver
* Improved
  - Default density fitting basis for heavy atoms
  - Density fitting MCSCF to allow inputing 3-center integrals
  - Rewriting NEVPT2 interface
  - Mole object serialization with json
  - Orbital energy output format for ROHF
* Bugfix
  - meta-lowdin orthogonalization for high angular memontum basis
  - Orbital occupancy for ROHF with symmetry
  - CASSCF initializing from x2c-UHF
  - ECP accuracy
  - QMMM interface


Version 1.1 alpha-2 (2016-3-8):
* Added
  - CCSD(T) and CCSD(T) gradients
  - General JK contraction function
  - RHF analytical nuclear Hessian
  - RKS analytical nuclear Hessian
  - Function to symmetrize given orbital space
  - General XC functional evaluator (using Libxc or Xcfun)
  - Intrinsic Atomic Orbital (IAO)
* Improved
  - NEVPT interface
  - Default DFT pruning scheme
  - Improving linear dependence issue for X2C module
* Bugfix
  - CCSD density matrix
  - Atomic radii for DFT grids
  - Handling h function for molden
  - Projecting CASSCF initial guess from orbitals of different shape

Version 1.1 alpha-1 (2016-2-8):
* Added
  - CCSD gradients
  - DMRG-NEVPT2 interface
  - DFT gradients
  - TDDFT and TDDFT gradients
  - DFT NMR
  - QM/MM interface
  - Pipek-Mezey localization
  - DF-CASSCF
  - State-specific CASSCF for excited states
  - Stream operations: apply, run, set
  - General basis value evaluator
  - DMRG (Block) examples
* Improved
  - Default DFT grids schemes (grid density, prune etc)


Version 1.0 (2015-10-8):
* 1.0 Release

Version 1.0 rc (2015-9-7):
* Add examples
* Add documents
* Optimize CCSD lambda solver and CCSD density matrix
* Optimize Boys localization.
* Tune CASSCF solver parameters
* Bug fixing for mcscf, localizer, nevpt2 and dft modules

Version 1.0 beta (2015-8-2):
* FCI spin eigen function
* Add state-average CASSCF
* CCSD lambda equation and density matrix

Version 1.0 alpha 2 (2015-7-3):
* Optimize HF J K contraction
* MP2 2 particle density matrix
* Default population analysis with meta-Lowdin orthogonalized AO
* Update FCI to handle more than 23 orbitals
* Multiple roots for FCI solver
* Optimize MCSCF convergence
* FCI/MCSCF wave function symmetry
* Z-matrix input
* Add chkfile_util script to analyze calculation on the fly
* CI determinants overlap
* Fix DIIS bug

Version 1.0-alpha (2015-4-7):
* D{\infty}h and C{\infty}v
* Fix bug in DFT screening functions

Version 0.11 (2015-3-6):
* Remove redundant module fci.direct_ms0
* Update the point group symmetry detect function
* Optimized DFT grids
* NEVPT2 (By S. Guo)
* X2C-1e HF
* Boys localization (By S. Wouters)
* Edmiston-Ruedenberg localization (By S. Wouters)
* Density fitting CASSCF

Version 0.10 (2015-2-4):
* Refactoring:
  - Expose class member functions to module level
  - Rename member function of class Mole,
    xxx_of_atm -> atom_xxx, xxx_of_bas -> bas_xxx
  - Rename scf.hf.scf_cycle to scf.hf.kernel
  - Rename conv_threshold to conv_tol
  - Rename hf.calc_tot_elec_energy to hf.energy_tot
  - Rename hf.set_mo_occ to hf.get_occ
  - unify variable names, mo -> mo_coeff, log -> verbose
  - Include nuclear repulsion in mcscf.e_tot
  - Add tests for most module level functions
  - Define update_casdm for CASSCF
* Add tests, cover ~ 90% of code
* Support molecular geometry string as input for Mole.atom
* Improve density fitting model for non-relativistic SCF
* Add documentation for whole package
* API updates:
  - Remove the first argument (Mole object) in CASSCF/CASCI class initialization
  - Change the return value ordering of function scf.hf.kernel
  - Set default value for the arguments of most class functions
* Removing the default calling of analyze() in kernel functions
* Fix screening bug in ao2mo.outcore for long-range separated molecule
* Add 4pdm

Version 0.9 (2015-1-4):
* Add 2-step FCIQMC-CASSCF, using NECI as FCI solver
* Solve Python 3.x compatibility
* general AO2MO integral transformation
* Add density fitting HF, DF-MP2

Version 0.8 (2014-12-21):
* Support OS X
* MCSCF for triplet
* Add symmetry support for MCSCF
* Add UHF-MCSCF
* Add 2-step DMRGSCF, using Block and CheMPS2 as FCI solver
* Add ROHF

Version 0.7 (2014-11-12):
* Fix memory leaks
* Runtime keywords checking
* Add MP2 density matrix
* Add FCI based on uhf integrals
* Add CCSD

Version 0.6 (2014-10-17):
* Fix bug in dhf
* add future/lo for localized orbital

Version 0.5 (2014-10-01):
* Change basis format
* Remove Cython dependence
* Upgrade dft to use libxc-2.0.0
* Add DFT, FCI, CASSCF, HF-gradients (NR and R), HF-NMR (NR and R)

Version 0.4 (2014-08-17):
* Module "future" for upcoming functions
* One-line command to run QC calculation with pyscf
* Fix bug of AO to MO transformation in OpenMP environment

Version 0.3 (2014-07-03):
* Change import layout

Version 0.2 (2014-05-08):
* Integral transformation

Version 0.1 (2014-05-03):
* Setup pyscf

