quspin.tools.misc.ints_to_array

quspin.tools.misc.ints_to_array(basis_ints, N=None)[source]

Converts QuSpin basis type integers to a state array with binary elements.

This function takes an array of batched QuSpin basis type integers and converts it to a batched state array with 0/1 elements representing spin-down/up or 0/1 occupation.

Parameters:

basis_ints: np.ndarray(int)

batched integers to be converted

N: int, optional

number of sites (doubled for spinful fermions), default to be the biggest size

represented by `basis_ints.dtype`.

Returns:

state_array: np.ndarray(np.uint8)

batched state array with binary entries

Notes

Conversion to higher spins or larger occupation numbers is not yet implemented.

Examples

 1from quspin.basis import spin_basis_general
 2from quspin.tools.misc import ints_to_array, array_to_ints
 3
 4N = 10
 5basis = spin_basis_general(N, make_basis=False)
 6
 7# initial states
 8num_states = 2
 9state_array = np.random.randint(0, 2, (num_states, N), dtype=np.uint8)
10print(f"The {num_states} initial states are")
11print(state_array)
12
13# convert state array to basis integers
14basis_ints = array_to_ints(state_array, basis.dtype)
15
16# apply Sx on site 4
17ME, bra, ket = basis.Op_bra_ket("x", [4], 1.0, np.float64, basis_ints)
18
19# convert outcome back to state array
20bra_array = ints_to_array(bra, N)
21
22print("Applying Sx on site 4, the new states are")
23print(bra_array)