ffsim.strings_to_addresses¶

ffsim.strings_to_addresses(strings, norb, nelec)[source]¶

Convert bitstrings to state vector addresses.

Example:

import numpy as np

import ffsim

norb = 3
nelec = (2, 1)
dim = ffsim.dim(norb, nelec)

addresses = ffsim.strings_to_addresses(
    [
        0b001011,
        0b010101,
        0b100101,
        0b010110,
        0b100110,
    ],
    norb,
    nelec,
)
print(addresses)  # prints [0 4 5 7 8]

addresses = ffsim.strings_to_addresses(
    [
        "001011",
        "010101",
        "100101",
        "010110",
        "100110",
    ],
    norb,
    nelec,
)
print(addresses)  # prints [0 4 5 7 8]

addresses = ffsim.strings_to_addresses(
    np.array(
        [
            [False, False, True, False, True, True],
            [False, True, False, True, False, True],
            [True, False, False, True, False, True],
            [False, True, False, True, True, False],
            [True, False, False, True, True, False],
        ]
    ),
    norb,
    nelec,
)
print(addresses)  # prints [0 4 5 7 8]

Parameters:

strings (Sequence[int] | Sequence[str] | ndarray) – The bitstrings to convert to state vector addresses. Can be a list of strings, a list of integers, or a Numpy array of bits.
norb (int) – The number of spatial orbitals.
nelec (int | tuple[int, int]) – Either a single integer representing the number of fermions for a spinless system, or a pair of integers storing the numbers of spin alpha and spin beta fermions.

Return type:

ndarray

Returns:

The state vector addresses, as a Numpy array of integers.