remove utils function for getting qubit order

qiskit/transpiler/passes/routing/stochastic_swap.py

@@ -25,7 +25,6 @@
 from qiskit.transpiler.passes.routing.utils import (
     route_cf_multiblock,
     route_cf_looping,
-    get_ordered_virtual_qubits,
     combine_permutations,
 )
 from qiskit.circuit import IfElseOp, WhileLoopOp, ForLoopOp, ControlFlowOp
@@ -254,10 +253,11 @@ def _layer_update(self, dag, layer, best_layout, best_depth, best_circuit):
             logger.debug("layer_update: there are no swaps in this layer")
         # Output this layer
         layer_circuit = layer["graph"]
-        order = combine_permutations(
-            get_ordered_virtual_qubits(self.initial_layout, dag.qregs),
-            get_ordered_virtual_qubits(layout, dag.qregs),
-        )
+        initial_v2p = self.initial_layout.get_virtual_bits()
+        new_v2p = layout.get_virtual_bits()
+        initial_order = [initial_v2p[qubit] for qubit in dag.qubits]
+        new_order = [new_v2p[qubit] for qubit in dag.qubits]
+        order = combine_permutations(initial_order, new_order)
         dag.compose(layer_circuit, qubits=order)
 
     def _mapper(self, circuit_graph, coupling_graph, trials=20):

qiskit/transpiler/passes/routing/utils.py

@@ -165,21 +165,6 @@ def route_cf_looping(tpass, cf_opnode, current_layout, root_dag, seed=None):
     return cf_op.replace_blocks([updated_circ_block]), current_layout, idle_qubits
 
 
-def get_ordered_virtual_qubits(layout, qregs):
-    """Get list of virtual qubits associated with ordered list
-    of physical qubits.
-
-    Args:
-        layout (Layout): circuit layout
-        qregs (list(QuantumRegister)): list of registers for circuit
-
-    Returns:
-        list(int): list of virtual qubit indices
-    """
-    p2v = layout.get_virtual_bits()
-    return [p2v[qubit] for qreg in qregs.values() for qubit in qreg]
-
-
 def combine_permutations(*permutations):
     """
     Chain a series of permutations.