qiskit_addon_sqd.fermion.bitstring_matrix_to_ci_strs

bitstring_matrix_to_ci_strs(bitstring_matrix, open_shell=False)[source]

Convert bitstrings (rows) in a bitstring_matrix into integer representations of determinants.

This function separates each bitstring in bitstring_matrix in half, flips the bits and translates them into integer representations, and finally appends them to their respective (spin-up or spin-down) lists. Those lists are sorted and output from this function.

Parameters:

  • bitstring_matrix (ndarray) – A 2D array of bool representations of bit values such that each row represents a single bitstring

  • open_shell (bool) – A flag specifying whether unique configurations from the left and right halves of the bitstrings should be kept separate. If False, configurations from the left and right halves of the bitstrings are combined into a single set of unique configurations. That combined set will be returned for both the left and right bitstrings.

Returns:

A length-2 tuple of determinant lists representing the right (spin-up) and left (spin-down) halves of the bitstrings, respectively.

Return type:

tuple[ndarray, ndarray]