Add pass to remove Phase gates (#1735)

pytket/binders/passes.cpp

@@ -679,6 +679,11 @@ PYBIND11_MODULE(passes, m) {
   m.def(
       "RemoveBarriers", &RemoveBarriers,
       "A pass to remove all barrier instructions from the circuit.");
+  m.def(
+      "RemovePhaseOps", &RemovePhaseOps,
+      "A pass to remove all Phase operations from the circuit. This includes "
+      "conditional Phase operations, but not Phase operations inside "
+      "CircBoxes, QControlBoxes or other nested structures.");
   m.def(
       "ZXGraphlikeOptimisation", &ZXGraphlikeOptimisation,
       "Attempt to optimise the circuit by simplifying in ZX calculus and "

pytket/conanfile.py

@@ -38,7 +38,7 @@ def requirements(self):
         self.requires("pybind11_json/0.2.15")
         self.requires("symengine/0.13.0")
         self.requires("tkassert/0.3.4@tket/stable")
-        self.requires("tket/1.3.60@tket/stable")
+        self.requires("tket/1.3.61@tket/stable")
         self.requires("tklog/0.3.3@tket/stable")
         self.requires("tkrng/0.3.3@tket/stable")
         self.requires("tktokenswap/0.3.9@tket/stable")

pytket/docs/changelog.rst

@@ -1,6 +1,13 @@
 Changelog
 =========
 
+Unreleased
+----------
+
+Features:
+
+* Add `RemovePhaseOps` pass.
+
 1.38.0 (January 2025)
 ---------------------
 

pytket/pytket/_tket/circuit.pyi

@@ -2574,7 +2574,7 @@ class Circuit:
     @property
     def wasm_uid(self) -> str | None:
         """
-        :return: the unique wasm uid of the circuit
+        :return: the unique WASM UID of the circuit, or `None` if the circuit has none
         """
 class ClBitVar:
     """

pytket/pytket/_tket/passes.pyi

@@ -9,7 +9,7 @@ import pytket._tket.transform
 import pytket._tket.unit_id
 import sympy
 import typing
-__all__ = ['AASRouting', 'Audit', 'AutoRebase', 'AutoSquash', 'BasePass', 'CNotSynthType', 'CXMappingPass', 'CliffordPushThroughMeasures', 'CliffordResynthesis', 'CliffordSimp', 'CnXPairwiseDecomposition', 'CommuteThroughMultis', 'ComposePhasePolyBoxes', 'ContextSimp', 'CustomPass', 'CustomRoutingPass', 'DecomposeArbitrarilyControlledGates', 'DecomposeBoxes', 'DecomposeClassicalExp', 'DecomposeMultiQubitsCX', 'DecomposeSingleQubitsTK1', 'DecomposeSwapsToCXs', 'DecomposeSwapsToCircuit', 'DecomposeTK2', 'Default', 'DefaultMappingPass', 'DelayMeasures', 'EulerAngleReduction', 'FlattenRegisters', 'FlattenRelabelRegistersPass', 'FullMappingPass', 'FullPeepholeOptimise', 'GlobalisePhasedX', 'GreedyPauliSimp', 'GuidedPauliSimp', 'HamPath', 'KAKDecomposition', 'NaivePlacementPass', 'NormaliseTK2', 'OptimisePhaseGadgets', 'PauliExponentials', 'PauliSimp', 'PauliSquash', 'PeepholeOptimise2Q', 'PlacementPass', 'RebaseCustom', 'RebaseTket', 'Rec', 'RemoveBarriers', 'RemoveDiscarded', 'RemoveImplicitQubitPermutation', 'RemoveRedundancies', 'RenameQubitsPass', 'RepeatPass', 'RepeatUntilSatisfiedPass', 'RepeatWithMetricPass', 'RoundAngles', 'RoutingPass', 'SWAP', 'SafetyMode', 'SequencePass', 'SimplifyInitial', 'SimplifyMeasured', 'SquashCustom', 'SquashRzPhasedX', 'SquashTK1', 'SynthesiseTK', 'SynthesiseTket', 'SynthesiseUMD', 'ThreeQubitSquash', 'ZXGraphlikeOptimisation', 'ZZPhaseToRz']
+__all__ = ['AASRouting', 'Audit', 'AutoRebase', 'AutoSquash', 'BasePass', 'CNotSynthType', 'CXMappingPass', 'CliffordPushThroughMeasures', 'CliffordResynthesis', 'CliffordSimp', 'CnXPairwiseDecomposition', 'CommuteThroughMultis', 'ComposePhasePolyBoxes', 'ContextSimp', 'CustomPass', 'CustomRoutingPass', 'DecomposeArbitrarilyControlledGates', 'DecomposeBoxes', 'DecomposeClassicalExp', 'DecomposeMultiQubitsCX', 'DecomposeSingleQubitsTK1', 'DecomposeSwapsToCXs', 'DecomposeSwapsToCircuit', 'DecomposeTK2', 'Default', 'DefaultMappingPass', 'DelayMeasures', 'EulerAngleReduction', 'FlattenRegisters', 'FlattenRelabelRegistersPass', 'FullMappingPass', 'FullPeepholeOptimise', 'GlobalisePhasedX', 'GreedyPauliSimp', 'GuidedPauliSimp', 'HamPath', 'KAKDecomposition', 'NaivePlacementPass', 'NormaliseTK2', 'OptimisePhaseGadgets', 'PauliExponentials', 'PauliSimp', 'PauliSquash', 'PeepholeOptimise2Q', 'PlacementPass', 'RebaseCustom', 'RebaseTket', 'Rec', 'RemoveBarriers', 'RemoveDiscarded', 'RemoveImplicitQubitPermutation', 'RemovePhaseOps', 'RemoveRedundancies', 'RenameQubitsPass', 'RepeatPass', 'RepeatUntilSatisfiedPass', 'RepeatWithMetricPass', 'RoundAngles', 'RoutingPass', 'SWAP', 'SafetyMode', 'SequencePass', 'SimplifyInitial', 'SimplifyMeasured', 'SquashCustom', 'SquashRzPhasedX', 'SquashTK1', 'SynthesiseTK', 'SynthesiseTket', 'SynthesiseUMD', 'ThreeQubitSquash', 'ZXGraphlikeOptimisation', 'ZZPhaseToRz']
 class BasePass:
     """
     Base class for passes.
@@ -618,6 +618,10 @@ def RemoveImplicitQubitPermutation() -> BasePass:
     
     Note that if the circuit contains measurements, they may become mid-circuit measurements in the transformed circuit.
     """
+def RemovePhaseOps() -> BasePass:
+    """
+    A pass to remove all Phase operations from the circuit. This includes conditional Phase operations, but not Phase operations inside CircBoxes, QControlBoxes or other nested structures.
+    """
 def RemoveRedundancies() -> BasePass:
     """
     Removes gate-inverse pairs, merges rotations, removes identity rotations, and removes redundant gates before measurement. Does not add any new gate types.

pytket/pytket/passes/script.py

@@ -41,6 +41,7 @@
     RebaseTket,
     RemoveBarriers,
     RemoveDiscarded,
+    RemovePhaseOps,
     RemoveRedundancies,
     RepeatPass,
     SequencePass,
@@ -85,6 +86,7 @@
     | rebase_tket
     | remove_barriers
     | remove_discarded
+    | remove_phase_ops
     | remove_redundancies
     | simplify_initial
     | simplify_initial_no_classical
@@ -127,6 +129,7 @@
 rebase_tket: "RebaseTket"
 remove_barriers: "RemoveBarriers"
 remove_discarded: "RemoveDiscarded"
+remove_phase_ops: "RemovePhaseOps"
 remove_redundancies: "RemoveRedundancies"
 simplify_initial: "SimplifyInitial"
 simplify_initial_no_classical: "SimplifyInitialNoClassical"
@@ -286,6 +289,9 @@ def remove_barriers(self, t: list) -> BasePass:
     def remove_discarded(self, t: list) -> BasePass:
         return RemoveDiscarded()
 
+    def remove_phase_ops(self, t: list) -> BasePass:
+        return RemovePhaseOps()
+
     def remove_redundancies(self, t: list) -> BasePass:
         return RemoveRedundancies()
 

pytket/tests/passes_serialisation_test.py

@@ -340,6 +340,7 @@ def nonparam_predicate_dict(name: str) -> Dict[str, Any]:
     "DecomposeSingleQubitsTK1",
     "RebaseTket",
     "RebaseUFR",
+    "RemovePhaseOps",
     "RemoveRedundancies",
     "SynthesiseTK",
     "SynthesiseTket",

pytket/tests/predicates_test.py

@@ -68,6 +68,7 @@
     RemoveBarriers,
     RemoveDiscarded,
     RemoveImplicitQubitPermutation,
+    RemovePhaseOps,
     RemoveRedundancies,
     RenameQubitsPass,
     RepeatPass,
@@ -496,6 +497,15 @@ def test_remove_barriers() -> None:
         assert cmd.op.type == OpType.CX
 
 
+def test_remove_phase_ops() -> None:
+    circ = Circuit(2, 2).H(0).H(1).measure_all()
+    circ0 = circ.copy()
+    circ.Phase(0.0)
+    circ.Phase(0.1, condition_bits=[Bit(0), Bit(1)], condition_value=3)
+    assert RemovePhaseOps().apply(circ)
+    assert circ == circ0
+
+
 def test_user_defined_swap_decomp() -> None:
     circ = Circuit(2)
     circ.SWAP(0, 1)

schemas/compiler_pass_v1.json

@@ -138,6 +138,7 @@
             "RemoveDiscarded",
             "SimplifyMeasured",
             "RemoveBarriers",
+            "RemovePhaseOps",
             "DecomposeBridges",
             "KAKDecomposition",
             "ThreeQubitSquash",
@@ -948,6 +949,7 @@
                   "RemoveDiscarded",
                   "SimplifyMeasured",
                   "RemoveBarriers",
+                  "RemovePhaseOps",
                   "DecomposeBridges"
                 ]
               }

tket/conanfile.py

@@ -23,7 +23,7 @@
 
 class TketConan(ConanFile):
     name = "tket"
-    version = "1.3.60"
+    version = "1.3.61"
     package_type = "library"
     license = "Apache 2"
     homepage = "https://github.com/CQCL/tket"

tket/include/tket/Predicates/PassLibrary.hpp

@@ -146,4 +146,7 @@ const PassPtr &RemoveImplicitQubitPermutation();
  */
 const PassPtr &ZXGraphlikeOptimisation();
 
+/** Remove all \ref OpType::Phase (including conditionals) from the circuit. */
+const PassPtr &RemovePhaseOps();
+
 }  // namespace tket

tket/src/Predicates/CompilerPass.cpp

@@ -449,6 +449,8 @@ PassPtr deserialise(
       pp = SimplifyMeasured();
     } else if (passname == "RemoveBarriers") {
       pp = RemoveBarriers();
+    } else if (passname == "RemovePhaseOps") {
+      pp = RemovePhaseOps();
     } else if (passname == "ComposePhasePolyBoxes") {
       pp = ComposePhasePolyBoxes(content.at("min_size").get<unsigned>());
     } else if (passname == "RebaseCustom") {

tket/src/Predicates/PassLibrary.cpp

@@ -17,6 +17,7 @@
 #include <memory>
 
 #include "tket/Converters/Converters.hpp"
+#include "tket/OpType/OpType.hpp"
 #include "tket/Predicates/CompilationUnit.hpp"
 #include "tket/Predicates/CompilerPass.hpp"
 #include "tket/Predicates/Predicates.hpp"
@@ -512,4 +513,34 @@ const PassPtr &ZXGraphlikeOptimisation() {
   return pp;
 }
 
+const PassPtr &RemovePhaseOps() {
+  static const PassPtr pp([]() {
+    Transform t = Transform([](Circuit &circ) {
+      VertexList phases;
+      BGL_FORALL_VERTICES(v, circ.dag, DAG) {
+        Op_ptr op = circ.get_Op_ptr_from_Vertex(v);
+        OpType optype = op->get_type();
+        bool conditional = optype == OpType::Conditional;
+        if (conditional) {
+          const Conditional &cond = static_cast<const Conditional &>(*op);
+          op = cond.get_op();
+          optype = op->get_type();
+        }
+        if (optype == OpType::Phase) {
+          phases.push_back(v);
+        }
+      }
+      circ.remove_vertices(
+          phases, Circuit::GraphRewiring::Yes, Circuit::VertexDeletion::Yes);
+      return !phases.empty();
+    });
+    const PredicatePtrMap no_precons;
+    PostConditions postcons = {{}, {}, Guarantee::Preserve};
+    nlohmann::json j;
+    j["name"] = "RemovePhaseOps";
+    return std::make_shared<StandardPass>(no_precons, t, postcons, j);
+  }());
+  return pp;
+}
+
 }  // namespace tket

tket/test/src/test_CompilerPass.cpp

@@ -619,6 +619,25 @@ SCENARIO("RemoveBarriers pass") {
   }
 }
 
+SCENARIO("RemovePhaseOps pass") {
+  GIVEN("A circuit containing Phase ops") {
+    Circuit circ(1, 1), circ0(1, 1);
+    circ.add_op<unsigned>(OpType::Phase, 0.1, {});
+    circ.add_op<unsigned>(OpType::H, {0});
+    circ0.add_op<unsigned>(OpType::H, {0});
+    circ.add_measure(0, 0);
+    circ0.add_measure(0, 0);
+    circ.add_conditional_gate<unsigned>(OpType::Phase, {0.2}, {}, {0}, 1);
+    circ.add_op<unsigned>(OpType::Phase, 0.3, {});
+    CompilationUnit cu(circ);
+    REQUIRE(RemovePhaseOps()->apply(cu));
+    const Circuit& circ1 = cu.get_circ_ref();
+    REQUIRE(circ1 == circ0);
+    CompilationUnit cu0(circ0);
+    REQUIRE_FALSE(RemovePhaseOps()->apply(cu0));
+  }
+}
+
 SCENARIO("gen_placement_pass test") {
   GIVEN("A simple circuit and device and base Placement.") {
     Circuit circ(4);

tket/test/src/test_json.cpp

@@ -935,6 +935,7 @@ SCENARIO("Test compiler pass serializations") {
   COMPPASSJSONTEST(SimplifyMeasured, SimplifyMeasured())
   COMPPASSJSONTEST(ZZPhaseToRz, ZZPhaseToRz())
   COMPPASSJSONTEST(RemoveBarriers, RemoveBarriers())
+  COMPPASSJSONTEST(RemovePhaseOps, RemovePhaseOps())
   COMPPASSJSONTEST(ComposePhasePolyBoxes, ComposePhasePolyBoxes())
   COMPPASSJSONTEST(DecomposeBridges, DecomposeBridges())
   COMPPASSJSONTEST(