Arbitrary qreg naming

pytket/phir/sharding/shards2ops.py

@@ -9,6 +9,8 @@
 from typing import TYPE_CHECKING, TypeAlias
 
 if TYPE_CHECKING:
+    from pytket.unit_id import UnitID
+
     from .shard import Shard, ShardLayer
 
 Layer: TypeAlias = list[list[int]]
@@ -22,6 +24,8 @@ def parse_shards_naive(
     shards_in_layer: list[ShardLayer] = []
     scheduled: set[int] = set()
     num_shards: int = len(shards)
+    qid_count: int = 0
+    qubits2ids: dict["UnitID", int] = {}
 
     while len(scheduled) < num_shards:
         layer: Layer = []
@@ -39,17 +43,31 @@ def parse_shards_naive(
             # if there are more than 2 qubits used, treat them all as parallel sq ops
             # one qubit will just be a single sq op
             # 3 or more will be 3 or more parallel sq ops
+            # when iterating through qubits,
+            # map all the qubits to a unique id to prevent duplicates in placement
             if len(shard.qubits_used) != 2:  # noqa: PLR2004
                 for qubit in shard.qubits_used:
-                    op = qubit.index
+                    qid, qid_count = get_qid(qubit, qubits2ids, qid_count)
+                    op = [qid]
                     layer.append(op)
             else:
                 for qubit in shard.qubits_used:
-                    op.append(qubit.index[0])
+                    qid, qid_count = get_qid(qubit, qubits2ids, qid_count)
+                    op.append(qid)
                 layer.append(op)
 
             scheduled.add(shard.ID)
 
         layers.append(layer)
 
     return layers, shards_in_layer
+
+
+def get_qid(
+    qubit: "UnitID", qubits2ids: dict["UnitID", int], qid_count: int
+) -> tuple[int, int]:
+    """Get qubit ID even if it is missing in the dict."""
+    qid = qubits2ids.setdefault(qubit, qid_count)
+    if qid == qid_count:
+        qid_count += 1
+    return qid, qid_count

tests/data/qasm/arbitrary_qreg_names.qasm

@@ -0,0 +1,40 @@
+OPENQASM 2.0;
+include "qelib1.inc";
+include "hqslib1_dev.inc";
+
+qreg q[2];
+qreg a[2];
+creg c[2];
+creg l[2];
+ry(0.5*pi) q[0];
+rx(3.5*pi) q[1];
+rz(3.5*pi) q[1];
+ZZ q[0],q[1];
+rz(3.5*pi) q[0];
+ry(3.5*pi) q[1];
+barrier q[0],q[1];
+rz(3.5*pi) q[0];
+rx(0.5*pi) q[1];
+ry(0.5*pi) q[1];
+ZZ q[0],q[1];
+ry(3.5*pi) q[0];
+rx(3.5*pi) q[1];
+barrier q[0],q[1];
+barrier q[0], a[0];
+x a[0];
+h a[0];
+ZZ q[0], a[0];
+barrier q[0], a[0];
+ZZ q[0], a[0];
+h a[0];
+measure a[0] -> l[0];
+measure q[0] -> c[0];
+barrier q[1], a[1];
+x a[1];
+h a[1];
+ZZ q[1], a[1];
+barrier q[1], a[1];
+ZZ q[1], a[1];
+h a[1];
+measure a[1] -> l[1];
+measure q[1] -> c[1];

tests/test_utils.py

@@ -47,6 +47,7 @@ class QasmFile(Enum):
     classical_ordering = auto()
     single_qubit_parallel_test = auto()
     exec_order_two_qubits = auto()
+    arbitrary_qreg_names = auto()
 
 
 class WatFile(Enum):