Common LCAO NLDF Infrastructure

The molecular NLDF implementation is divided between PySCF adapters and a host-independent linear-combination-of-atomic-orbitals (LCAO) layer. The classes on this page define the atom-centered grid indexing, auxiliary Gaussian convolutions, and grid/basis interpolation used by the PySCF forward and adjoint paths.

Atom-centered grid indexing

class ciderpress.dft.grids_indexer.AtomicGridsIndexer

AtomicGridsIndexer relates PySCF’s sorted and screened quadrature points to atom, radial shell, angular point, and spherical-harmonic indices. Energy, potential, and grid-response operations share this mapping.

Auxiliary Gaussian convolutions

class ciderpress.dft.lcao_convolutions.ATCBasis

class ciderpress.dft.lcao_convolutions.ConvolutionCollection

class ciderpress.dft.lcao_convolutions.ConvolutionCollectionK

ATCBasis stores the atom-centered auxiliary Gaussian basis and its angular layout. ConvolutionCollection builds the matrices that convolve the source expansion for version-I/J features; ConvolutionCollectionK supplies the corresponding version-K operations.

Grid/basis interpolation

class ciderpress.dft.lcao_interpolation.LCAOInterpolator

class ciderpress.dft.lcao_interpolation.LCAOInterpolatorDirect

The interpolators transfer fields between the atom-centered auxiliary basis and molecular quadrature points. Their forward and backward methods form the pair used for NLDF values and potentials. The direct variant treats the on-site contribution explicitly and is used by the packaged molecular NLDF path.

NLDF orchestration

class ciderpress.dft.lcao_nldf_generator.LCAONLDFGenerator

LCAONLDFGenerator combines an exponent-interpolation plan, convolution collection, and LCAO interpolator. The PySCF-specific PyscfNLDFGenerator constructs these objects from a molecule and its CIDER grid.

See Numerical Evaluation of NLDF Features for the mathematical description and PySCF Numerical and Derivative Implementation for the PySCF numerical implementation details.