Add rebase functionality to QasmModule

pyqasm/elements.py

@@ -162,3 +162,21 @@ def __repr__(self) -> str:
             f"value = {self.value}, is_constant = {self.is_constant}, "
             f"readonly = {self.readonly}, is_register = {self.is_register})"
         )
+
+
+class BasisSet(Enum):
+    """
+    Enum for the different basis sets in Qasm.
+    """
+
+    DEFAULT = 0
+    TOFFOLI = 1
+    CLIFFORD = 2
+    PAULI = 3
+
+    def __repr__(self):
+        return f"<{self.__class__.__name__}.{self.name}: {self.value}>"
+
+    @staticmethod
+    def get_supported_bases():
+        return list(BasisSet)

pyqasm/maps.py

@@ -36,7 +36,7 @@
     UintType,
 )
 
-from pyqasm.elements import InversionOp
+from pyqasm.elements import BasisSet, InversionOp
 from pyqasm.exceptions import ValidationError
 from pyqasm.linalg import kak_decomposition_angles
 
@@ -691,6 +691,31 @@ def two_qubit_gate_op(
     "cswap": cswap_gate,
 }
 
+BASIS_GATE_MAP = {
+    # default basis set is the gate set of the stdgates.inc library file
+    BasisSet.DEFAULT: {
+        "id",
+        "rx",
+        "ry",
+        "rz",
+        "h",
+        "x",
+        "y",
+        "z",
+        "s",
+        "sx",
+        "t",
+        "sdg",
+        "tdg",
+        "cx",
+        "cz",
+        "swap",
+    },
+    BasisSet.CLIFFORD: {"h", "t", "s", "cx"},
+    BasisSet.PAULI: {"rx", "ry", "rz", "cx"},
+    BasisSet.TOFFOLI: {"h", "ccx"},
+}
+
 
 def map_qasm_op_to_callable(op_name: str):
     """

pyqasm/modules/base.py

@@ -20,7 +20,7 @@
 from openqasm3.ast import Include, Program
 
 from pyqasm.analyzer import Qasm3Analyzer
-from pyqasm.elements import ClbitDepthNode, QubitDepthNode
+from pyqasm.elements import BasisSet, ClbitDepthNode, QubitDepthNode
 from pyqasm.exceptions import UnrollError, ValidationError
 from pyqasm.maps import QUANTUM_STATEMENTS
 from pyqasm.visitor import QasmVisitor
@@ -445,6 +445,41 @@ def reverse_qubit_order(self, in_place=True):
         # 4. return the module
         return qasm_module
 
+    def _transform_to_basis(self, basis_set: BasisSet):
+        """Transform the unrolled module to a new basis set
+
+        Args:
+            basis_set (BasisSet): The basis set to transform the module to
+
+        Returns:
+            None
+        """
+        if basis_set == BasisSet.DEFAULT:
+            return
+
+
+    def rebase(self, basis_set: BasisSet = BasisSet.DEFAULT, in_place=True):
+        """Rebases an openqasm program to a new gate set.
+        Will unroll the module if not already done.
+
+        Args:
+            basis_set (BasisSet): The new gate set to rebase the program to.
+
+        Returns:
+            QasmModule: The module rebased to the new gate set. If in_place is False, a new module
+                        with the rebased gate set is returned.
+
+        """
+
+        if not isinstance(basis_set, BasisSet):
+            raise TypeError(f"'gate_set' must be one of {BasisSet.get_supported_bases()}")
+
+        qasm_module = self if in_place else self.copy()
+        qasm_module.unroll()
+        qasm_module._transform_to_basis(basis_set)
+
+        return qasm_module
+
     def validate(self):
         """Validate the module"""
         if self._validated_program is True: