Add user choice between U3 or GPI2 as single-qubit native gate

doc/source/code-examples/advancedexamples.rst

@@ -2011,10 +2011,9 @@ Multiple transpilation steps can be implemented using the :class:`qibo.transpile
     from qibo import gates
     from qibo.models import Circuit
     from qibo.transpiler.pipeline import Passes, assert_transpiling
-    from qibo.transpiler.abstract import NativeType
     from qibo.transpiler.optimizer import Preprocessing
     from qibo.transpiler.router import ShortestPaths
-    from qibo.transpiler.unroller import NativeGates
+    from qibo.transpiler.unroller import Unroller, NativeGates
     from qibo.transpiler.placer import Random
 
     # Define connectivity as nx.Graph
@@ -2040,10 +2039,10 @@ Multiple transpilation steps can be implemented using the :class:`qibo.transpile
     # Routing step
     custom_passes.append(ShortestPaths(connectivity=star_connectivity()))
     # Gate decomposition step
-    custom_passes.append(NativeGates(two_qubit_natives=NativeType.iSWAP))
+    custom_passes.append(Unroller(native_gates=NativeGates.default()))
 
     # Define the general pipeline
-    custom_pipeline = Passes(custom_passes, connectivity=star_connectivity(), native_gates=NativeType.iSWAP)
+    custom_pipeline = Passes(custom_passes, connectivity=star_connectivity(), native_gates=NativeGates.default())
 
     # Call the transpiler pipeline on the circuit
     transpiled_circ, final_layout = custom_pipeline(circuit)
@@ -2057,10 +2056,10 @@ Multiple transpilation steps can be implemented using the :class:`qibo.transpile
         connectivity=star_connectivity(),
         initial_layout=initial_layout,
         final_layout=final_layout,
-        native_gates=NativeType.iSWAP
+        native_gates=NativeGates.default()
     )
 
 In this case circuits will first be transpiled to respect the 5-qubit star connectivity, with qubit 2 as the middle qubit. This will potentially add some SWAP gates.
-Then all gates will be converted to native. The :class:`qibo.transpiler.unroller.NativeGates` transpiler used in this example assumes Z, RZ, GPI2 or U3 as
+Then all gates will be converted to native. The :class:`qibo.transpiler.unroller.Unroller` transpiler used in this example assumes Z, RZ, GPI2 or U3 as
 the single-qubit native gates, and supports CZ and iSWAP as two-qubit natives. In this case we restricted the two-qubit gate set to CZ only.
 The final_layout contains the final logical-physical qubit mapping.

src/qibo/transpiler/abstract.py

@@ -1,35 +1,11 @@
 from abc import ABC, abstractmethod
-from enum import Flag, auto
 from typing import Tuple
 
 import networkx as nx
 
-from qibo import gates
-from qibo.config import raise_error
 from qibo.models import Circuit
 
 
-class NativeType(Flag):
-    """Define available types of native gates.
-
-    Should have the same names with qibo gates.
-    """
-
-    M = auto()
-    Z = auto()
-    RZ = auto()
-    GPI2 = auto()
-    CZ = auto()
-    iSWAP = auto()
-
-    @classmethod
-    def from_gate(cls, gate: gates.Gate):
-        try:
-            return getattr(cls, gate.__class__.__name__)
-        except AttributeError:
-            raise ValueError(f"Gate {gate} cannot be used as native.")
-
-
 class Placer(ABC):
     @abstractmethod
     def __init__(self, connectivity: nx.Graph, *args):
@@ -72,51 +48,11 @@ class Optimizer(ABC):
 
     @abstractmethod
     def __call__(self, circuit: Circuit, *args) -> Circuit:
-        """Find initial qubit mapping
+        """Optimize transpiled circuit.
 
         Args:
             circuit (:class:`qibo.models.circuit.Circuit`): circuit to be optimized
 
         Returns:
             (:class:`qibo.models.circuit.Circuit`): circuit with optimized number of gates.
         """
-
-
-class Unroller(ABC):
-    @abstractmethod
-    def __init__(self, native_gates: NativeType, *args):
-        """An unroller decomposes gates into native gates."""
-
-    @abstractmethod
-    def __call__(self, circuit: Circuit, *args) -> Circuit:
-        """Find initial qubit mapping
-
-        Args:
-            circuit (:class:`qibo.models.circuit.Circuit`): circuit to be optimized
-
-        Returns:
-            (:class:`qibo.models.circuit.Circuit`): circuit with native gates.
-        """
-
-
-def _find_gates_qubits_pairs(circuit: Circuit):
-    """Translate qibo circuit into a list of pairs of qubits to be used by the router and placer.
-
-    Args:
-        circuit (:class:`qibo.models.circuit.Circuit`): circuit to be transpiled.
-
-    Returns:
-        (list): list containing qubits targeted by two qubit gates.
-    """
-    translated_circuit = []
-    for gate in circuit.queue:
-        if isinstance(gate, gates.M):
-            pass
-        elif len(gate.qubits) == 2:
-            translated_circuit.append(sorted(gate.qubits))
-        elif len(gate.qubits) >= 3:
-            raise_error(
-                ValueError, "Gates targeting more than 2 qubits are not supported"
-            )
-
-    return translated_circuit