[Issue 14] Rebasing + avoiding Phase gate with ser/de (#19)

* Adding ser/de pass to fix phase gate issue

* removing comment

* adding test for all qasm files

* changing log cli level

* Applying recommended approach for decomposing circuits and ignoring phase

* checking for phase gates within conditionals

* adding check

---------

Co-authored-by: Neal Erickson <neal.erickson@quantinuum.com>

pytket/phir/rebasing/rebaser.py

@@ -3,6 +3,7 @@
 from pytket.extensions.quantinuum.backends.quantinuum import (
     QuantinuumBackend,
 )
+from pytket.passes import DecomposeBoxes
 
 
 def rebase_to_qtm_machine(circuit: Circuit, qtm_machine: str) -> Circuit:
@@ -13,6 +14,10 @@ def rebase_to_qtm_machine(circuit: Circuit, qtm_machine: str) -> Circuit:
         machine_debug=False,
         api_handler=qapi_offline,  # type: ignore [arg-type]
     )
+
+    # Decompose boxes to ensure no problematic phase gates
+    DecomposeBoxes().apply(circuit)
+
     # Optimization level 0 includes rebasing and little else
     # see: https://cqcl.github.io/pytket-quantinuum/api/#default-compilation
     return backend.get_compiled_circuit(circuit, 0)

pytket/phir/sharding/sharder.py

@@ -14,6 +14,7 @@
     OpType.SetBits,
     OpType.ClassicalExpBox,  # some classical operations are rolled up into a box
     OpType.RangePredicate,
+    OpType.ExplicitPredicate,
 ]
 
 logger = logging.getLogger(__name__)
@@ -46,8 +47,15 @@ def shard(self) -> list[Shard]:
         -------
             list of Shards needed to schedule
         """
-        logger.debug("Sharding begins....")
-        for command in self._circuit.get_commands():
+        logger.debug("Sharding beginning")
+        commands = self._circuit.get_commands()
+
+        if logger.isEnabledFor(logging.DEBUG):
+            logger.debug("All commands:")
+            for command in commands:
+                logger.debug(command)
+
+        for command in commands:
             self._process_command(command)
         self._cleanup_remaining_commands()
 
@@ -69,6 +77,10 @@ def _process_command(self, command: Command) -> None:
             msg = f"OpType {command.op.type} not supported!"
             raise NotImplementedError(msg)
 
+        if self._is_command_global_phase(command):
+            logger.debug("Ignoring global Phase gate")
+            return
+
         if self.should_op_create_shard(command.op):
             logger.debug(
                 f"Building shard for command: {command}",
@@ -77,6 +89,12 @@ def _process_command(self, command: Command) -> None:
         else:
             self._add_pending_sub_command(command)
 
+    def _is_command_global_phase(self, command: Command) -> bool:
+        return command.op.type == OpType.Phase or (
+            command.op.type == OpType.Conditional
+            and cast(Conditional, command.op).op.type == OpType.Phase
+        )
+
     def _build_shard(self, command: Command) -> None:
         """Builds a shard.
 
@@ -165,10 +183,10 @@ def _add_pending_sub_command(self, command: Command) -> None:
         Args:
             command:  tket command (operation, bits, etc)
         """
-        key = command.qubits[0]
-        if key not in self._pending_commands:
-            self._pending_commands[key] = []
-        self._pending_commands[key].append(command)
+        qubit_key = command.qubits[0]
+        if qubit_key not in self._pending_commands:
+            self._pending_commands[qubit_key] = []
+        self._pending_commands[qubit_key].append(command)
         logger.debug(
             f"Adding pending command {command}",
         )

tests/test_api.py

@@ -1,8 +1,14 @@
+import logging
+
+import pytest
+
 from pytket.phir.api import pytket_to_phir
 from pytket.phir.qtm_machine import QtmMachine
 
 from .sample_data import QasmFile, get_qasm_as_circuit
 
+logger = logging.getLogger(__name__)
+
 
 class TestApi:
     def test_pytket_to_phir_no_machine(self) -> None:
@@ -11,9 +17,9 @@ def test_pytket_to_phir_no_machine(self) -> None:
 
         assert pytket_to_phir(circuit)
 
-    def test_pytket_to_phir_h1_1(self) -> None:
+    @pytest.mark.parametrize("test_file", list(QasmFile))
+    def test_pytket_to_phir_h1_1_all_circuits(self, test_file: QasmFile) -> None:
         """Standard case."""
-        circuit = get_qasm_as_circuit(QasmFile.baby)
+        circuit = get_qasm_as_circuit(test_file)
 
-        # TODO(neal): Make this test more valuable once PHIR is actually returned
         assert pytket_to_phir(circuit, QtmMachine.H1_1)