feat!: qubits are now reset on allocation, and dirty_qubit added (#…

…325) Closes #322 BREAKING CHANGE: `qubit`s are now reset on allocation --------- Co-authored-by: Mark Koch <[email protected]>
CQCL · Jul 25, 2024 · 4a9e205 · 4a9e205
1 parent 314409c
commit 4a9e205
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Showing 3 changed files with 46 additions and 3 deletions.
diff --git a/guppylang/prelude/_internal.py b/guppylang/prelude/_internal.py
@@ -26,7 +26,14 @@
 from guppylang.tys.builtin import bool_type, int_type, list_type
 from guppylang.tys.const import ConstValue
 from guppylang.tys.subst import Inst, Subst
-from guppylang.tys.ty import FunctionType, NoneType, NumericType, Type, unify
+from guppylang.tys.ty import (
+    FunctionType,
+    NoneType,
+    NumericType,
+    Type,
+    type_to_row,
+    unify,
+)
 
 
 class ConstInt(BaseModel):
@@ -442,3 +449,16 @@ def compile(self, args: list[OutPortV]) -> list[OutPortV]:
             quantum_op("QFree"), inputs=[measure.add_out_port(qubit.ty)]
         )
         return [measure.add_out_port(bool_type())]
+
+
+class QAllocCompiler(CustomCallCompiler):
+    """Compiler for the `qubit` function."""
+
+    def compile(self, args: list[OutPortV]) -> list[OutPortV]:
+        from .quantum import quantum_op
+
+        [qubit_ty] = type_to_row(get_type(self.node))
+        qalloc = self.graph.add_node(quantum_op("QAlloc"), inputs=args)
+        qalloc_result = qalloc.add_out_port(qubit_ty)
+        reset = self.graph.add_node(quantum_op("Reset"), inputs=[qalloc_result])
+        return [reset.add_out_port(qubit_ty)]
diff --git a/guppylang/prelude/quantum.py b/guppylang/prelude/quantum.py
@@ -8,7 +8,7 @@
 from guppylang.decorator import guppy
 from guppylang.hugr_builder.hugr import UNDEFINED
 from guppylang.module import GuppyModule
-from guppylang.prelude._internal import MeasureCompiler
+from guppylang.prelude._internal import MeasureCompiler, QAllocCompiler
 
 quantum = GuppyModule("quantum")
 
@@ -28,10 +28,14 @@ def quantum_op(op_name: str) -> ops.OpType:
     linear=True,
 )
 class qubit:
-    @guppy.hugr_op(quantum, quantum_op("QAlloc"))
+    @guppy.custom(quantum, QAllocCompiler())
     def __new__() -> "qubit": ...
 
 
+@guppy.hugr_op(quantum, quantum_op("QAlloc"))
+def dirty_qubit() -> qubit: ...
+
+
 @guppy.hugr_op(quantum, quantum_op("H"))
 def h(q: qubit) -> qubit: ...
 

diff --git a/tests/integration/test_qalloc.py b/tests/integration/test_qalloc.py
@@ -0,0 +1,19 @@
+from guppylang.decorator import guppy
+from guppylang.module import GuppyModule
+from guppylang.prelude.quantum import qubit
+
+import guppylang.prelude.quantum as quantum
+from guppylang.prelude.quantum import cx, measure, dirty_qubit
+
+
+def test_dirty_qubit(validate):
+    module = GuppyModule("test")
+    module.load(quantum)
+
+    @guppy(module)
+    def test() -> tuple[bool, bool]:
+        q1, q2 = qubit(), dirty_qubit()
+        q1, q2 = cx(q1, q2)
+        return (measure(q1), measure(q2))
+
+    validate(module.compile())