purge `get_subsystem_statevector`
@@ -22,25 +22,6 @@ from collections import defaultdict
from qiskit.tools.qi.qi import partial_trace
-# def get_subsystem_statevector(statevector, trace_systems):
-# """
-# Compute the statevector of the quantum subsystem.
-#
-# Args:
-# statevector (list|array): The state vector of the complete system
-# trace_systems (list|range): The indices of the qubits to be traced.
-# to trace qubits 0 and 4 trace_systems = [0,4]
-#
-# Returns:
-# The state vector of the desired subsystem
-# """
-# rho = np.outer(statevector, statevector)
-# rho_sub = partial_trace(rho, trace_systems)
-# u, s, v = np.linalg.svd(rho_sub)
-# state_sub = np.dot(s, v)
-# return state_sub
-
-
def get_subsystem_density_matrix(statevector, trace_systems):
"""
Compute the reduced density matrix of a quantum subsystem.
