Merge pull request #437 from jaeyoo/add_fp_type_in_mps_sim

Support ApplyFusedGate in MPSSimulator
quantumlib · Sep 30, 2021 · da4cc61 · da4cc61
2 parents 96a85d8 + 016af85
commit da4cc61
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Showing 4 changed files with 111 additions and 3 deletions.
diff --git a/lib/mps_simulator.h b/lib/mps_simulator.h
@@ -35,11 +35,12 @@ namespace mps {
 /**
  *  Truncated Matrix Product State (MPS) circuit simulator w/ vectorization.
  */
-template <typename For, typename fp_type = float>
+template <typename For, typename FP = float>
 class MPSSimulator final {
  public:
-  using MPSStateSpace_ = MPSStateSpace<For, fp_type>;
+  using MPSStateSpace_ = MPSStateSpace<For, FP>;
   using State = typename MPSStateSpace_::MPS;
+  using fp_type = typename MPSStateSpace_::fp_type;
 
   using Complex = std::complex<fp_type>;
   using Matrix =

diff --git a/lib/mps_statespace.h b/lib/mps_statespace.h
@@ -51,10 +51,11 @@ inline void free(void* ptr) {
  * Class containing context and routines for fixed bond dimension
  * truncated Matrix Product State (MPS) simulation.
  */
-template <typename For, typename fp_type = float>
+template <typename For, typename FP = float>
 class MPSStateSpace {
  private:
  public:
+  using fp_type = FP;
   using Pointer = std::unique_ptr<fp_type, decltype(&detail::free)>;
 
   using Complex = std::complex<fp_type>;

diff --git a/tests/BUILD b/tests/BUILD
@@ -613,6 +613,7 @@ cc_test(
         "@com_google_googletest//:gtest_main",
         "//lib:gate_appl",
         "//lib:gates_cirq",
+        "//lib:gates_qsim",
         "//lib:mps_simulator",
         "//lib:formux",
     ],

diff --git a/tests/mps_simulator_test.cc b/tests/mps_simulator_test.cc
@@ -17,6 +17,7 @@
 #include "../lib/formux.h"
 #include "../lib/gate_appl.h"
 #include "../lib/gates_cirq.h"
+#include "../lib/gates_qsim.h"
 #include "gtest/gtest.h"
 
 namespace qsim {
@@ -802,6 +803,110 @@ TEST(MPSSimulator, OneTwoQubitFuzz) {
   */
 }
 
+TEST(MPSSimulator, ApplyFusedGateLeft) {
+  // Apply a fused gate matrix to the first two qubits.
+  // Compute the state vector of:
+  //   |     |     |
+  // +-+-----+-+   |
+  // |FusedGate|   |
+  // +-+-----+-+   |
+  //   |     |     |
+  // +-+-+ +-+-+ +-+-+
+  // | 0 +-+ 1 +-+ 2 |
+  // +---+ +---+ +---+
+  auto sim = MPSSimulator<For, float>(1);
+  using MPSStateSpace = MPSSimulator<For, float>::MPSStateSpace_;
+  auto ss = MPSStateSpace(1);
+
+  auto gate1 = GateCZ<float>::Create(2, 0, 1);
+  auto gate2 = GateHd<float>::Create(0, 0);
+  auto gate3 = GateHd<float>::Create(0, 1);
+
+  GateFused<GateQSim<float>> fgate1{kGateCZ, 2, {0, 1}, &gate1,
+                                    {&gate2, &gate3}};
+  auto mps = ss.Create(3, 4);
+  ss.SetStateZero(mps);
+  ApplyFusedGate(sim, fgate1, mps);
+
+  float wf[32];
+  float ground_truth[] = {0.5, 0., 0., 0., 0.5, 0., 0., 0.,
+                          0.5, 0., 0., 0., 0.5, 0., 0., 0.};
+  ss.ToWaveFunction(mps, wf);
+  for (int i = 0; i < 16; i++) {
+    EXPECT_NEAR(wf[i], ground_truth[i], 1e-4);
+  }
+}
+
+TEST(MPSSimulator, ApplyFusedGateRight) {
+  // Apply a fused gate matrix to the last two qubits.
+  // Compute the state vector of:
+  //   |     |     |
+  //   |   +-+-----+-+
+  //   |   |FusedGate|
+  //   |   +-+-----+-+ 
+  //   |     |     |
+  // +-+-+ +-+-+ +-+-+
+  // | 0 +-+ 1 +-+ 2 |
+  // +---+ +---+ +---+
+  auto sim = MPSSimulator<For, float>(1);
+  using MPSStateSpace = MPSSimulator<For, float>::MPSStateSpace_;
+  auto ss = MPSStateSpace(1);
+
+  auto gate1 = GateCZ<float>::Create(2, 1, 2);
+  auto gate2 = GateHd<float>::Create(0, 1);
+  auto gate3 = GateHd<float>::Create(0, 2);
+
+  GateFused<GateQSim<float>> fgate1{kGateCZ, 2, {1, 2}, &gate1,
+                                    {&gate2, &gate3}};
+  auto mps = ss.Create(3, 4);
+  ss.SetStateZero(mps);
+  ApplyFusedGate(sim, fgate1, mps);
+
+  float wf[32];
+  float ground_truth[] = {0.5, 0., 0.5, 0., 0.5, 0., 0.5, 0.,
+                          0., 0., 0., 0., 0., 0., 0., 0.};
+  ss.ToWaveFunction(mps, wf);
+  for (int i = 0; i < 16; i++) {
+    EXPECT_NEAR(wf[i], ground_truth[i], 1e-4);
+  }
+}
+
+TEST(MPSSimulator, ApplyFusedGateMiddle) {
+  // Apply a fused gate matrix to the middle two qubits.
+  // Compute the state vector of:
+  //   |     |     |     |
+  //   |   +-+-----+-+   |
+  //   |   |FusedGate|   |
+  //   |   +-+-----+-+   |
+  //   |     |     |     |
+  // +-+-+ +-+-+ +-+-+ +-+-+
+  // | 0 +-+ 1 +-+ 2 |-| 3 |
+  // +---+ +---+ +---+ +-+-+
+  auto sim = MPSSimulator<For, float>(1);
+  using MPSStateSpace = MPSSimulator<For, float>::MPSStateSpace_;
+  auto ss = MPSStateSpace(1);
+
+  auto gate1 = GateCZ<float>::Create(2, 1, 2);
+  auto gate2 = GateHd<float>::Create(0, 1);
+  auto gate3 = GateHd<float>::Create(0, 2);
+
+  GateFused<GateQSim<float>> fgate1{kGateCZ, 2, {1, 2}, &gate1,
+                                    {&gate2, &gate3}};
+  auto mps = ss.Create(4, 4);
+  ss.SetStateZero(mps);
+  ApplyFusedGate(sim, fgate1, mps);
+
+  float wf[64];
+  float ground_truth[] = {0.5, 0., 0., 0., 0.5, 0., 0., 0.,
+                          0.5, 0., 0., 0., 0.5, 0., 0., 0.,
+                          0., 0., 0., 0., 0., 0., 0., 0.,
+                          0., 0., 0., 0., 0., 0., 0., 0.};
+  ss.ToWaveFunction(mps, wf);
+  for (int i = 0; i < 32; i++) {
+    EXPECT_NEAR(wf[i], ground_truth[i], 1e-4);
+  }
+}
+
 }  // namespace
 }  // namespace mps
 }  // namespace qsim