Use AutoRebase in tk_to_qiskit rather than RebaseCustom (#387)

* use AutoRebase instead of RebaseCustom

* remove unused Union import

Author: CalMacCQ

pytket/extensions/qiskit/qiskit_convert.py

@@ -19,7 +19,6 @@
 from typing import (
     Callable,
     Optional,
-    Union,
     Any,
     Iterable,
     cast,
@@ -82,7 +81,7 @@
 from pytket.pauli import Pauli, QubitPauliString
 from pytket.architecture import Architecture, FullyConnected
 from pytket.utils import QubitPauliOperator, gen_term_sequence_circuit
-from pytket.passes import RebaseCustom
+from pytket.passes import AutoRebase
 
 if TYPE_CHECKING:
     from qiskit_ibm_runtime.ibm_backend import IBMBackend  # type: ignore
@@ -762,9 +761,6 @@ def append_tk_command_to_qiskit(
     return qcirc.append(g, qargs=qargs)
 
 
-# Define varibles for RebaseCustom
-_cx_replacement = Circuit(2).CX(0, 1)
-
 # The set of tket gates that can be converted directly to qiskit gates
 _supported_tket_gates = set(_known_gate_rev_phase.keys())
 
@@ -779,18 +775,8 @@ def append_tk_command_to_qiskit(
 )
 
 
-Param = Union[float, "sympy.Expr"]  # Type for TK1 and U3 parameters
-
-
-# Use the U3 gate for tk1_replacement as this is a member of _supported_tket_gates
-def _tk1_to_u3(a: Param, b: Param, c: Param) -> Circuit:
-    tk1_circ = Circuit(1)
-    tk1_circ.add_gate(OpType.U3, [b, a - 1 / 2, c + 1 / 2], [0]).add_phase(-(a + c) / 2)
-    return tk1_circ
-
-
 # This is a rebase to the set of tket gates which have an exact substitution in qiskit
-supported_gate_rebase = RebaseCustom(_protected_tket_gates, _cx_replacement, _tk1_to_u3)
+supported_gate_rebase = AutoRebase(_protected_tket_gates)
 
 
 def tk_to_qiskit(