Convert amplitudes for use with singlet UCCSD

The output list contains only those amplitudes that are relevant to singlet UCCSD, in an order suitable for use with the function uccsd_singlet_generator.

single_amplitudes(ndarray): [NxN] array storing single excitation amplitudes corresponding to t[i,j] * (a_i^\dagger a_j - H.C.) double_amplitudes(ndarray): [NxNxNxN] array storing double excitation amplitudes corresponding to t[i,j,k,l] * (a_i^\dagger a_j a_k^\dagger a_l - H.C.) n_qubits(int): Number of spin-orbitals used to represent the system, which also corresponds to number of qubits in a non-compact map. n_electrons(int): Number of electrons in the physical system.

packed_amplitudes(list): List storing the unique single and double excitation amplitudes for a singlet UCCSD operator. The ordering lists unique single excitations before double excitations.