Ensure CXMappingPass works on circuits containing barriers or wire …

…swaps (#1598)
CQCL · Sep 30, 2024 · f1c1cf2 · f1c1cf2
1 parent 953d3a8
commit f1c1cf2
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Showing 5 changed files with 26 additions and 4 deletions.
diff --git a/pytket/conanfile.py b/pytket/conanfile.py
@@ -38,7 +38,7 @@ def requirements(self):
         self.requires("pybind11_json/0.2.14")
         self.requires("symengine/0.12.0")
         self.requires("tkassert/0.3.4@tket/stable")
-        self.requires("tket/1.3.29@tket/stable")
+        self.requires("tket/1.3.30@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")

diff --git a/pytket/docs/changelog.rst b/pytket/docs/changelog.rst
@@ -17,6 +17,7 @@ Fixes:
 
 * Fix QASM conversion of non-register-aligned `MultiBitOp`.
 * Fix `DecomposeClassicalExp()` when target occurs in expression.
+* Allow barriers and wire swaps in `DecomposeSwapsToCXs()`.
 
 1.32.0 (September 2024)
 -----------------------

diff --git a/tket/conanfile.py b/tket/conanfile.py
@@ -23,7 +23,7 @@
 
 class TketConan(ConanFile):
     name = "tket"
-    version = "1.3.29"
+    version = "1.3.30"
     package_type = "library"
     license = "Apache 2"
     homepage = "https://github.com/CQCL/tket"

diff --git a/tket/src/Predicates/PassGenerators.cpp b/tket/src/Predicates/PassGenerators.cpp
@@ -780,15 +780,14 @@ PassPtr gen_decompose_routing_gates_to_cxs_pass(
     OpTypeSet in_optypes = out_optypes;
     in_optypes.insert(OpType::SWAP);
     in_optypes.insert(OpType::BRIDGE);
+    in_optypes.insert(OpType::Barrier);
     PredicatePtr twoqbpred = std::make_shared<MaxTwoQubitGatesPredicate>();
     PredicatePtr connected = std::make_shared<ConnectivityPredicate>(arc);
-    PredicatePtr wireswaps = std::make_shared<NoWireSwapsPredicate>();
     PredicatePtr directedpred = std::make_shared<DirectednessPredicate>(arc);
     PredicatePtr ingates = std::make_shared<GateSetPredicate>(in_optypes);
     PredicatePtr outgates = std::make_shared<GateSetPredicate>(out_optypes);
     precons = {
         CompilationUnit::make_type_pair(connected),
-        CompilationUnit::make_type_pair(wireswaps),
         CompilationUnit::make_type_pair(ingates)};
     s_postcons = {
         CompilationUnit::make_type_pair(directedpred),

diff --git a/tket/test/src/test_CompilerPass.cpp b/tket/test/src/test_CompilerPass.cpp
@@ -1612,6 +1612,28 @@ SCENARIO("CX mapping pass") {
       REQUIRE_THROWS_AS(pass->apply(cu), UnsatisfiedPredicate);
     }
   }
+  GIVEN("CXMappingPass preconditions") {
+    // https://github.com/CQCL/tket/issues/1597
+    // Construct a circuit with a barrier and an implicit wire swap; check that
+    // we can apply CXMappingPass.
+    Circuit c(2, 2);
+    c.add_op<unsigned>(OpType::CX, {0, 1});
+    c.add_op<unsigned>(OpType::CX, {1, 0});
+    c.add_barrier({0, 1});
+    c.add_op<unsigned>(OpType::CX, {0, 1});
+    c.add_measure(0, 0);
+    c.add_measure(1, 1);
+    Transforms::clifford_simp().apply(c);
+    CHECK(c.has_implicit_wireswaps());
+    std::vector<std::pair<unsigned, unsigned>> edges = {{0, 1}};
+    Architecture arc(edges);
+    Placement::Ptr plptr = std::make_shared<Placement>(arc);
+    std::vector<RoutingMethodPtr> config = {
+        std::make_shared<LexiRouteRoutingMethod>()};
+    PassPtr p = gen_cx_mapping_pass(arc, plptr, config, true, false);
+    CompilationUnit cu(c);
+    REQUIRE_NOTHROW(p->apply(cu));
+  }
 }
 
 SCENARIO("ThreeQubitSquah") {