Module scf 

Self-Consistent Field (SCF) Iterative Driver Self-Consistent Field (SCF) Iterative Driver

Solves the generalized Roothaan-Hall equation (FC = SCE) to find the molecular ground state electronic energy.

Implements Direct Inversion in the Iterative Subspace (DIIS) to aggressively accelerate convergence, strictly bounded within the zero-heap constraints.

Structs

RhfResult

Converged RHF result: the electronic energy plus everything a caller needs to compute post-SCF observables (orbital energies for HOMO/LUMO, the density and overlap-consistent MO coefficients for Mulliken populations and the dipole).

Enums

ScfError

ScfFormalism

Constants

DIIS_SUBSPACE_SIZE

Subspace size for DIIS. Maximum historical Fock/Density/Error vectors kept.

MAX_SCF_ITERATIONS

SCF_CONVERGENCE_THRESHOLD

Functions

gaussian_elimination

Gaussian elimination solver for small DIIS mixing matrices. Solves Ax = b where A is an N x N matrix, returning x. All done strictly on the stack.

jacobi_diagonalization

Zero-heap Jacobi eigenvalue algorithm for real symmetric matrices. Returns eigenvalues and eigenvectors.

orthogonalization_matrix

Calculate symmetric orthogonalization matrix X = S^(-1/2)

solve_rhf_scf

Perform a full Restricted Hartree-Fock SCF iteration with DIIS

solve_rhf_scf_4index

Full Restricted Hartree-Fock SCF with a REAL 4-index two-electron contraction and DIIS acceleration.

transpose

Helper function to perform matrix transposition on zero heap.