Update quantum trajectories.

CMakeLists.txt

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-cmake_minimum_required(VERSION 3.31)
+cmake_minimum_required(VERSION 3.28)
 project(qsim LANGUAGES CXX)
 
 include(CheckLanguage)

Makefile

@@ -171,9 +171,9 @@ run-tests tests: $(TESTS)
 
 .PHONY: check-cuquantum-root-set
 check-cuquantum-root-set:
-	@if [[ -z "$(CUQUANTUM_ROOT)" ]]; then \
-	    echo Error: '$$CUQUANTUM_ROOT must be set in order to use cuStateVec.' \
-	    exit 1 \
+	@if test -z "$(CUQUANTUM_ROOT)"; then \
+	    echo Error: '$$CUQUANTUM_ROOT must be set in order to use cuStateVec.'; \
+	    exit 1; \
 	fi
 
 eigen:

apps/qsim_qtrajectory_cuda.cu

@@ -30,6 +30,7 @@
 #include "../lib/gates_qsim.h"
 #include "../lib/io_file.h"
 #include "../lib/qtrajectory.h"
+#include "../lib/run_qsim.h"
 #include "../lib/simulator_cuda.h"
 
 struct Options {
@@ -190,7 +191,7 @@ int main(int argc, char* argv[]) {
   using fp_type = float;
 
   struct Factory {
-    using Simulator = qsim::SimulatorCUDA<float>;
+    using Simulator = qsim::SimulatorCUDA<fp_type>;
     using StateSpace = Simulator::StateSpace;
 
     Factory(const StateSpace::Parameter& param) : param(param) {}
@@ -209,17 +210,18 @@ int main(int argc, char* argv[]) {
   using Simulator = Factory::Simulator;
   using StateSpace = Simulator::StateSpace;
   using State = StateSpace::State;
-  using Fuser = MultiQubitGateFuser<IO, GateQSim<fp_type>>;
-  using QTSimulator = QuantumTrajectorySimulator<IO, GateQSim<fp_type>,
-                                                 MultiQubitGateFuser,
-                                                 Simulator>;
+  using Gate = GateQSim<fp_type>;
+  using Fuser = MultiQubitGateFuser<IO, Gate>;
+  using FuserQT = MultiQubitGateFuser<IO, const Gate*>;
+  using RunnerQT = QSimRunner<IO, FuserQT, Factory>;
+  using QTSimulator = QuantumTrajectorySimulator<IO, Gate, RunnerQT>;
 
   auto opt = GetOptions(argc, argv);
   if (!ValidateOptions(opt)) {
     return 1;
   }
 
-  Circuit<GateQSim<fp_type>> circuit;
+  Circuit<Gate> circuit;
   unsigned maxtime = opt.times.back();
   if (!CircuitQsimParser<IOFile>::FromFile(maxtime, opt.circuit_file,
                                            circuit)) {
@@ -254,7 +256,7 @@ int main(int argc, char* argv[]) {
 
   auto noisy_circuits = AddNoise(circuit, opt.times, channel1, channel2);
 
-  auto observables = GetObservables<GateQSim<fp_type>>(circuit.num_qubits);
+  auto observables = GetObservables<Gate>(circuit.num_qubits);
 
   std::vector<std::vector<std::vector<std::complex<double>>>> results;
   results.reserve(opt.num_trajectories);

lib/BUILD

@@ -475,6 +475,7 @@ cc_library(
     name = "run_qsim",
     hdrs = ["run_qsim.h"],
     deps = [
+        ":circuit",
         ":gate",
         ":gate_appl",
         ":util",
@@ -636,7 +637,6 @@ cuda_library(
     name = "simulator_custatevec",
     hdrs = [
         "simulator_custatevec.h",
-        "simulator_custatevec_kernels.h",
     ],
     deps = [
         ":bits",

lib/circuit.h

@@ -31,6 +31,49 @@ struct Circuit {
   std::vector<Gate> gates;
 };
 
+namespace detail {
+
+/**
+ * An adapter for vectors of gates.
+ */
+template <typename Circuit>
+struct Gates;
+
+template <typename Gate>
+struct Gates<qsim::Circuit<Gate>> {
+  static const std::vector<Gate>& get(const qsim::Circuit<Gate>& circuit) {
+    return circuit.gates;
+  }
+
+  static const Gate& gate(const Gate& g) {
+    return g;
+  }
+};
+
+template <typename Gate>
+struct Gates<std::vector<Gate>> {
+  static const std::vector<Gate>& get(const std::vector<Gate>& gates) {
+    return gates;
+  }
+
+  static const Gate& gate(const Gate& g) {
+    return g;
+  }
+};
+
+template <typename Gate>
+struct Gates<std::vector<Gate*>> {
+  static const std::vector<Gate*>& get(const std::vector<Gate*>& gates) {
+    return gates;
+  }
+
+  static const Gate& gate(const Gate* g) {
+    return *g;
+  }
+};
+
+}  // namespace detail
+
 }  // namespace qsim
 
 #endif  // CIRCUIT_H_

lib/qtrajectory.h

@@ -31,19 +31,18 @@ namespace qsim {
  * Quantum trajectory simulator.
  */
 template <typename IO, typename Gate,
-          template <typename, typename> class FuserT, typename Simulator,
-          typename RGen = std::mt19937>
+          typename Runner, typename RGen = std::mt19937>
 class QuantumTrajectorySimulator {
  public:
-  using Fuser = FuserT<IO, const Gate*>;
+  using Simulator = typename Runner::Simulator;
   using StateSpace = typename Simulator::StateSpace;
-  using State = typename Simulator::State;
+  using State = typename StateSpace::State;
   using MeasurementResult = typename StateSpace::MeasurementResult;
 
   /**
    * User-specified parameters for the simulator.
    */
-  struct Parameter : public Fuser::Parameter {
+  struct Parameter : public Runner::Parameter {
     /**
      * If true, collect statistics of sampled Kraus operator indices.
      */
@@ -265,7 +264,8 @@ class QuantumTrajectorySimulator {
       if (channel[0].kind == gate::kMeasurement) {
         // Measurement channel.
 
-        if (!ApplyDeferredOps(param, num_qubits, simulator, gates, state)) {
+        if (!ApplyDeferredOps(
+                 param, num_qubits, state_space, simulator, gates, state)) {
           return false;
         }
 
@@ -309,7 +309,8 @@ class QuantumTrajectorySimulator {
 
       if (r < cp) continue;
 
-      if (!ApplyDeferredOps(param, num_qubits, simulator, gates, state)) {
+      if (!ApplyDeferredOps(
+               param, num_qubits, state_space, simulator, gates, state)) {
         return false;
       }
 
@@ -351,7 +352,8 @@ class QuantumTrajectorySimulator {
     }
 
     if (apply_last_deferred_ops || !stat.primary) {
-      if (!ApplyDeferredOps(param, num_qubits, simulator, gates, state)) {
+      if (!ApplyDeferredOps(
+               param, num_qubits, state_space, simulator, gates, state)) {
         return false;
       }
 
@@ -372,20 +374,13 @@ class QuantumTrajectorySimulator {
   }
 
   static bool ApplyDeferredOps(
-      const Parameter& param, unsigned num_qubits, const Simulator& simulator,
+      const Parameter& param, unsigned num_qubits,
+      const StateSpace& state_space, const Simulator& simulator,
       std::vector<const Gate*>& gates, State& state) {
     if (gates.size() > 0) {
-      auto fgates = Fuser::FuseGates(param, num_qubits, gates);
-
+      bool rc = Runner::Run(param, gates, state_space, simulator, state);
       gates.resize(0);
-
-      if (fgates.size() == 0) {
-        return false;
-      }
-
-      for (const auto& fgate : fgates) {
-        ApplyFusedGate(simulator, fgate, state);
-      }
+      return rc;
     }
 
     return true;

lib/run_qsim.h

@@ -19,6 +19,7 @@
 #include <string>
 #include <vector>
 
+#include "circuit.h"
 #include "gate.h"
 #include "gate_appl.h"
 #include "util.h"
@@ -174,6 +175,56 @@ struct QSimRunner final {
   static bool Run(const Parameter& param, const Factory& factory,
                   const Circuit& circuit, State& state,
                   std::vector<MeasurementResult>& measure_results) {
+    StateSpace state_space = factory.CreateStateSpace();
+    Simulator simulator = factory.CreateSimulator();
+
+    return Run(param, circuit, state_space, simulator, state, measure_results);
+  }
+
+  /**
+   * Runs the given circuit and make the final state available to the caller,
+   * discarding the result of any intermediate measurements in the circuit.
+   * @param param Options for gate fusion, parallelism and logging.
+   * @param factory Object to create simulators and state spaces.
+   * @param circuit The circuit to be simulated.
+   * @param state As an input parameter, this should contain the initial state
+   *   of the system. After a successful run, it will be populated with the
+   *   final state of the system.
+   * @return True if the simulation completed successfully; false otherwise.
+   */
+  template <typename Circuit>
+  static bool Run(const Parameter& param, const Factory& factory,
+                  const Circuit& circuit, State& state) {
+    StateSpace state_space = factory.CreateStateSpace();
+    Simulator simulator = factory.CreateSimulator();
+
+    std::vector<MeasurementResult> discarded_results;
+
+    return Run(
+        param, circuit, state_space, simulator, state, discarded_results);
+  }
+
+  /**
+   * Runs the given circuit and make the final state available to the caller,
+   * recording the result of any intermediate measurements in the circuit.
+   * @param param Options for gate fusion, parallelism and logging.
+   * @param circuit The circuit to be simulated.
+   * @param state_space StateSpace object required to perform measurements.
+   * @param simulator Simulator object. Provides specific implementations for
+   *   applying gates.
+   * @param state As an input parameter, this should contain the initial state
+   *   of the system. After a successful run, it will be populated with the
+   *   final state of the system.
+   * @param measure_results As an input parameter, this should be empty.
+   *   After a successful run, this will contain all measurements results from
+   *   the run, ordered by time and qubit index.
+   * @return True if the simulation completed successfully; false otherwise.
+   */
+  template <typename Circuit>
+  static bool Run(const Parameter& param, const Circuit& circuit,
+                  const StateSpace& state_space, const Simulator& simulator,
+                  State& state,
+                  std::vector<MeasurementResult>& measure_results) {
     double t0 = 0.0;
     double t1 = 0.0;
 
@@ -183,19 +234,18 @@ struct QSimRunner final {
 
     RGen rgen(param.seed);
 
-    StateSpace state_space = factory.CreateStateSpace();
-    Simulator simulator = factory.CreateSimulator();
-
     if (param.verbosity > 1) {
       t1 = GetTime();
       IO::messagef("init time is %g seconds.\n", t1 - t0);
       t0 = GetTime();
     }
 
-    auto fused_gates = Fuser::FuseGates(param, circuit.num_qubits,
-                                        circuit.gates);
+    using Gates = detail::Gates<Circuit>;
+    const auto& gates = Gates::get(circuit);
 
-    if (fused_gates.size() == 0 && circuit.gates.size() > 0) {
+    auto fused_gates = Fuser::FuseGates(param, state.num_qubits(), gates);
+
+    if (fused_gates.size() == 0 && gates.size() > 0) {
       return false;
     }
 
@@ -242,18 +292,23 @@ struct QSimRunner final {
    * Runs the given circuit and make the final state available to the caller,
    * discarding the result of any intermediate measurements in the circuit.
    * @param param Options for gate fusion, parallelism and logging.
-   * @param factory Object to create simulators and state spaces.
    * @param circuit The circuit to be simulated.
+   * @param state_space StateSpace object required to perform measurements.
+   * @param simulator Simulator object. Provides specific implementations for
+   *   applying gates.
    * @param state As an input parameter, this should contain the initial state
    *   of the system. After a successful run, it will be populated with the
    *   final state of the system.
    * @return True if the simulation completed successfully; false otherwise.
    */
   template <typename Circuit>
-  static bool Run(const Parameter& param, const Factory& factory,
-                  const Circuit& circuit, State& state) {
+  static bool Run(const Parameter& param, const Circuit& circuit,
+                  const StateSpace& state_space, const Simulator& simulator,
+                  State& state) {
     std::vector<MeasurementResult> discarded_results;
-    return Run(param, factory, circuit, state, discarded_results);
+
+    return Run(
+        param, circuit, state_space, simulator, state, discarded_results);
   }
 };
 

lib/simulator_custatevec.h

@@ -66,7 +66,7 @@ class SimulatorCuStateVec final {
       uint64_t size = uint64_t{1} << state.num_qubits();
 
       if (StateSpace::is_float) {
-        cuComplex a = {matrix[0], matrix[1]};
+        cuComplex a = {(float) matrix[0], (float) matrix[1]};
         auto p = (cuComplex*) state.get();
         ErrorCheck(cublasCscal(cublas_handle_, size, &a, p, 1));
       } else {

lib/vectorspace.h

@@ -74,7 +74,7 @@ class VectorSpace {
       return num_qubits_;
     }
 
-    bool requires_copy_to_host() const {
+    static constexpr bool requires_copy_to_host() {
       return false;
     }
 
@@ -174,7 +174,7 @@ class VectorSpace {
     return true;
   }
 
-  void DeviceSync() {}
+  static void DeviceSync() {}
 
  protected:
   For for_;

lib/vectorspace_cuda.h

@@ -72,7 +72,7 @@ class VectorSpaceCUDA {
       return num_qubits_;
     }
 
-    bool requires_copy_to_host() const {
+    static constexpr bool requires_copy_to_host() {
       return true;
     }
 
@@ -160,7 +160,7 @@ class VectorSpaceCUDA {
     return true;
   }
 
-  void DeviceSync() {
+  static void DeviceSync() {
     ErrorCheck(cudaDeviceSynchronize());
   }
 

pybind_interface/avx2/CMakeLists.txt

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-cmake_minimum_required(VERSION 3.31)
+cmake_minimum_required(VERSION 3.28)
 project(qsim)
 
 IF (WIN32)