exatomic.core.matrices module

Matrices

For handling matrices of common dimensionality in QM calcs.

class exatomic.core.matrices.Triangle(*args, **kwargs)

Bases: _Symmetric

Triangular matrices having dimensions N * (N + 1) // 2 sharing natural indices all belong in the same table. As applied to exatomic that includes but is not limited to:

• one-electron integrals (overlap, kinetic, nuclear attraction energies,

  multipole integrals, etc.)

Note

When parsing matrices like these, it may be more efficient to have indices chi0 and chi1 not in the same order as they may be for other matrices of the same dimensions. This can be dangerous if one then adds a column expecting different index ordering. Therefore, it is recommended to only add columns to this table by using the merge bound method and instances of this class.

merge(other, column=None)

Correctly adds a column, ensuring that if index ordering is not the same between two instances, that it is remedied.