add a test to the new gray code m_ctrl gen

Signed-off-by: Alex McCaskey <mccaskeyaj@ornl.gov>

quantum/plugins/algorithms/qpe/ControlledGateApplicator.cpp

@@ -290,11 +290,12 @@ bool ControlledU::expand(const xacc::HeterogeneousMap &runtimeOptions) {
 
   auto ctrlU = uComposite;
 
-  auto should_run_gray_mcu_synth = [ctrlU,&ctrlIdxs]() {
+  auto should_run_gray_mcu_synth = [ctrlU, &ctrlIdxs]() {
     if (ctrlU->nInstructions() == 1) {
       std::vector<std::string> allowed{"Z"};
       auto inst = ctrlU->getInstruction(0);
-      if (xacc::container::contains(allowed, inst->name()) && ctrlIdxs.size() > 2) {
+      if (xacc::container::contains(allowed, inst->name()) &&
+          ctrlIdxs.size() > 2) {
         return true;
       }
     }
@@ -303,6 +304,30 @@ bool ControlledU::expand(const xacc::HeterogeneousMap &runtimeOptions) {
 
   if (should_run_gray_mcu_synth()) {
     ctrlU = __gray_code_mcu_gen(ctrlU, ctrlIdxs);
+    std::vector<int> zero_rotation_idxs;
+    for (int i = 0; i < ctrlU->nInstructions(); i++) {
+      auto inst = ctrlU->getInstruction(i);
+      if (inst->name() == "U") {
+        auto p0 = inst->getParameter(0);
+        auto p1 = inst->getParameter(1);
+        auto p2 = inst->getParameter(2);
+        if (p0.isNumeric() && p1.isNumeric() && p2.isNumeric()) {
+          if (std::fabs(xacc::InstructionParameterToDouble(p0)) < 1e-12 &&
+              std::fabs(xacc::InstructionParameterToDouble(p1)) < 1e-12 &&
+              std::fabs(xacc::InstructionParameterToDouble(p2)) < 1e-12) {
+            // std::cout << "Removing " << inst->toString() << "\n";
+            // inst->disable();
+            zero_rotation_idxs.push_back(i);
+          }
+        }
+      }
+    }
+
+    for (auto iter = zero_rotation_idxs.rbegin();
+         iter != zero_rotation_idxs.rend(); ++iter) {
+      ctrlU->removeInstruction(*iter);
+    }
+
   } else {
 
     // Recursive application of control bits:

quantum/plugins/algorithms/qpe/tests/ControlledGateTester.cpp

@@ -3,7 +3,7 @@
 #include "xacc_service.hpp"
 #include "CommonGates.hpp"
 #include <Eigen/Dense>
-#include "GateFusion.hpp"
+#include "CountGatesOfTypeVisitor.hpp"
 
 using namespace xacc;
 using namespace xacc::quantum;
@@ -283,7 +283,7 @@ TEST(ControlledGateTester, checkControlSwap)
 
 TEST(ControlledGateTester, checkEltonBug) {
     auto gateRegistry = xacc::getService<xacc::IRProvider>("quantum");
-    auto z = std::make_shared<Z>(5);
+    auto z = std::make_shared<Z>(4);
     z->setBufferNames(std::vector<std::string>{"q"});
 
     std::shared_ptr<xacc::CompositeInstruction> comp =
@@ -293,16 +293,24 @@ TEST(ControlledGateTester, checkEltonBug) {
         xacc::getService<Instruction>("C-U"));
     const std::vector<int> ctrl_idxs{0,1,2,3};
     multi_ctrl_z->expand({{"U", comp}, {"control-idx", ctrl_idxs}});
-    auto opt = xacc::getIRTransformation("circuit-optimizer");
-    opt->apply(multi_ctrl_z, nullptr);
+
     std::cout << "HOWDY: \n" << multi_ctrl_z->toString() << "\n";
     std::cout << multi_ctrl_z->nInstructions() << "\n";
 
-    Eigen::MatrixXcd expected = Eigen::MatrixXcd::Identity(32,32);
-    expected(31,31) = -1;
-    std::cout << expected << "\n";
+    // Eigen::MatrixXcd expected = Eigen::MatrixXcd::Identity(32,32);
+    // expected(31,31) = -1;
+    // std::cout << expected << "\n";
+
+    xacc::quantum::CountGatesOfTypeVisitor<CNOT> vis(multi_ctrl_z);
+    xacc::quantum::CountGatesOfTypeVisitor<U> visu(multi_ctrl_z);
+
+
+    // QiskitImpl Reports: OrderedDict([('cx', 44), ('p', 30), ('u', 30)])
+    // all ours are U+CX, and we remove U(0,0,0). 
+    // There are 8 U(0,0,0). So should have 44 CX, 60-8=52 Us
+    EXPECT_EQ(vis.countGates(), 44);
+    EXPECT_EQ(visu.countGates(), 52);
 
-    // FIXME Need to test
 
 }