auto register channels on circuit class

Author: refraction-ray

CHANGELOG.md

@@ -30,6 +30,8 @@
 
 - Add `tc.utils.arg_alias` which is a decorator that adds alias argument for function with the doc fixed accordingly
 
+- Add quantum channel auto resgisteration method in `Circuit` class
+
 ### Changed
 
 - `rxx`, `ryy`, `rzz` gates now has 1/2 factor before theta consitent with `rx`, `ry`, `rz` gates. (breaking change)
@@ -54,6 +56,8 @@
 
 - Fix `arg_alias` when the docstring for each argument is in multiple lines
 
+- Noise channel apply methods in `DMCircuit` can also absorb `status` keyword (directly omitting it) for a consistent API with `Circuit`
+
 ## 0.3.1
 
 ### Added

tensorcircuit/circuit.py

@@ -11,6 +11,7 @@
 import tensornetwork as tn
 
 from . import gates
+from . import channels
 from .cons import backend, contractor, dtypestr, npdtype
 from .quantum import QuOperator, identity
 from .simplify import _full_light_cone_cancel
@@ -255,6 +256,7 @@ def depolarizing2(
         # roughly benchmark shows that performance of two depolarizing in terms of
         # building time and running time are similar
 
+    # overwritten now, deprecated
     def depolarizing(
         self,
         index: int,
@@ -414,6 +416,7 @@ def step_function(x: Tensor) -> Tensor:
 
         if status is None:
             status = backend.implicit_randu()[0]
+        status = backend.convert_to_tensor(status)
         status = backend.real(status)
         prob_cumsum = backend.cast(prob_cumsum, dtype=status.dtype)  # type: ignore
         r = step_function(status)
@@ -576,6 +579,46 @@ def general_kraus(
 
     apply_general_kraus = general_kraus
 
+    @staticmethod
+    def apply_general_kraus_delayed(
+        krausf: Callable[..., Sequence[Gate]]
+    ) -> Callable[..., None]:
+        def apply(
+            self: "Circuit",
+            *index: int,
+            status: Optional[float] = None,
+            name: Optional[str] = None,
+            **vars: float,
+        ) -> None:
+            kraus = krausf(**vars)
+            self.apply_general_kraus(kraus, *index, status=status, name=name)
+
+        return apply
+
+    @classmethod
+    def _meta_apply_channels(cls) -> None:
+        for k in channels.channels:
+            setattr(
+                cls,
+                k,
+                cls.apply_general_kraus_delayed(getattr(channels, k + "channel")),
+            )
+            doc = """
+            Apply %s quantum channel on the circuit.
+            See :py:meth:`tensorcircuit.channels.%schannel`
+
+            :param index: Qubit number that the gate applies on.
+            :type index: int.
+            :param status: uniform external random number between 0 and 1
+            :type status: Tensor
+            :param vars: Parameters for the channel.
+            :type vars: float.
+            """ % (
+                k,
+                k,
+            )
+            getattr(cls, k).__doc__ = doc
+
     def is_valid(self) -> bool:
         """
         [WIP], check whether the circuit is legal.
@@ -757,6 +800,7 @@ def expectation(  # type: ignore
 
 
 Circuit._meta_apply()
+Circuit._meta_apply_channels()
 
 
 def expectation(

tensorcircuit/densitymatrix.py

@@ -203,6 +203,10 @@ def apply_general_kraus_delayed(
         krausf: Callable[..., Sequence[Gate]]
     ) -> Callable[..., None]:
         def apply(self: "DMCircuit", *index: int, **vars: float) -> None:
+            for key in ["status", "name"]:
+                if key in vars:
+                    del vars[key]
+            # compatibility with circuit API
             kraus = krausf(**vars)
             self.apply_general_kraus(kraus, [index])
 
@@ -339,6 +343,9 @@ def apply_general_kraus_delayed(
         krausf: Callable[..., Sequence[Gate]]
     ) -> Callable[..., None]:
         def apply(self: "DMCircuit2", *index: int, **vars: float) -> None:
+            for key in ["status", "name"]:
+                if key in vars:
+                    del vars[key]
             kraus = krausf(**vars)
             self.apply_general_kraus(kraus, *index)
 

tests/test_circuit.py

@@ -1152,3 +1152,12 @@ def test_sample_format(backend):
                         random_generator=key,
                     ),
                 )
+
+
+@pytest.mark.parametrize("backend", [lf("npb"), lf("tfb"), lf("jaxb")])
+def test_channel_auto_register(backend, highp):
+    c = tc.Circuit(2)
+    c.H(0)
+    c.reset(0, status=0.8)
+    s = c.state()
+    np.testing.assert_allclose(s[0], 1.0, atol=1e-9)