update conversion to use symengine (#314)

* update conversion to use symengine

* update version and changelog

* fix mypy

_metadata.py

@@ -1,2 +1,2 @@
-__extension_version__ = "0.51.0"
+__extension_version__ = "0.51.1rc0"
 __extension_name__ = "pytket-qiskit"

docs/changelog.rst

@@ -1,11 +1,12 @@
 Changelog
 ~~~~~~~~~
 
-Unreleased
-----------
+0.51.1rc0 (April 2024)
+----------------------
 
 * Update pytket version requirement to 1.26.
 * Update qiskit-aer version requirement to 0.14.
+* Update conversion to qiskit to use symengine for symbolic circuits
 
 0.51.0 (March 2024)
 -------------------

pytket/extensions/qiskit/qiskit_convert.py

@@ -34,6 +34,7 @@
 from uuid import UUID
 
 import numpy as np
+from symengine import sympify  # type: ignore
 
 import sympy
 import qiskit.circuit.library.standard_gates as qiskit_gates  # type: ignore
@@ -580,7 +581,7 @@ def param_to_qiskit(
     if len(ppi.free_symbols) == 0:
         return float(ppi.evalf())
     else:
-        return ParameterExpression(symb_map, ppi)
+        return ParameterExpression(symb_map, sympify(ppi))
 
 
 def _get_params(
@@ -724,7 +725,7 @@ def append_tk_command_to_qiskit(
 
     if optype == OpType.TK1:
         params = _get_params(op, symb_map)
-        half = ParameterExpression(symb_map, sympy.pi / 2)
+        half = ParameterExpression(symb_map, sympify(sympy.pi / 2))
         qcirc.global_phase += -params[0] / 2 - params[2] / 2
         return qcirc.append(
             qiskit_gates.UGate(params[1], params[0] - half, params[2] + half),
@@ -749,7 +750,7 @@ def append_tk_command_to_qiskit(
     if type(phase) == float:
         qcirc.global_phase += phase * np.pi
     else:
-        qcirc.global_phase += phase * sympy.pi
+        qcirc.global_phase += sympify(phase * sympy.pi)
     return qcirc.append(g, qargs=qargs)