openfermion.utils.map_two_pdm_to_one_pdm

Contract a 2-RDM to a 1-RDM

Main aliases

openfermion.utils.map_two_pdm_to_one_pdm(
    tpdm, particle_number
)

Args
`tpdm`	`numpy.ndarray` The 2-RDM as a 4-index tensor. Indices follow the internal convention of tpdm[p, q, r, s] == \(a_{p}^{\dagger}a_{q}^{\dagger}a_{r}a_{s}\).
`particle_number`	`float` number of particles in the system

Args

tpdm

numpy.ndarray

The 2-RDM as a 4-index tensor. Indices follow the internal convention of tpdm[p, q, r, s] == \(a_{p}^{\dagger}a_{q}^{\dagger}a_{r}a_{s}\).

particle_number

float

number of particles in the system

Returns
`opdm`	`numpy.ndarray` The 1-RDM contracted from the tpdm.

opdm

numpy.ndarray

The 1-RDM contracted from the tpdm.

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Last updated 2025-06-06 UTC.