ffsim.random.random_t2_amplitudes_spinless

ffsim.random.random_t2_amplitudes_spinless(norb, nocc, *, seed=None, dtype=<class 'complex'>)

Sample random t2 amplitudes for spinless fermions.

The t2 amplitudes of spinless fermions satisfy t2[i, j, a, b] == -t2[j, i, a, b] == -t2[i, j, b, a]. This is also the symmetry of the same-spin blocks of unrestricted t2 amplitudes. The independent entries t2[i, j, a, b] with i < j and a < b are sampled independently from the standard normal distribution if dtype is a real type, and from the standard complex normal distribution if dtype is a complex type.

Parameters:

• norb (int) – The number of orbitals.

• nocc (int) – The number of orbitals that are occupied by a fermion.

• seed – A seed to initialize the pseudorandom number generator. Should be a valid input to np.random.default_rng.

• dtype – The data type to use for the result.

Return type:

ndarray

Returns:

The sampled t2 amplitudes tensor.