Commit 68210c68 authored by Nguyen, Thien Minh's avatar Nguyen, Thien Minh
Browse files

Support Measure return for FTQC 



We want the runtime mz to return a boolean in FTQC. For NISQ, the boolean return is just a dummy one.

Whenever we need to use the return value of the Measure (e.g. assignment or conditional), it's parsed as a classical instruction.

Hence, we just need to do token replacement in that code path.

Also, fixing the `else` path of the token collector to prevent it from combining the next line (could be a quantum instruction) into the `else` line.

Signed-off-by: default avatarThien Nguyen <nguyentm@ornl.gov>
parent 1758ac20

examples/ftqc_qrt/bit-flip-code.cpp

+5 −8
Original line number Diff line number Diff line
@@ -45,18 +45,16 @@ __qpu__ void correctLogicalQubit(qreg q, int logicalIdx, int ancIdx) { 
  // Assume that we only has 1 ancilla qubit

  CX(q[physicalIdx], q[ancIdx]);

  CX(q[physicalIdx + 1], q[ancIdx]);

  Measure(q[ancIdx]);

  const bool parity01 = q.creg[ancIdx];

  if (q.creg[ancIdx]) {

  const bool parity01 = Measure(q[ancIdx]);

  if (parity01) {

    // Reset anc qubit for reuse

    X(q[ancIdx]);

  }



  CX(q[physicalIdx + 1], q[ancIdx]);

  CX(q[physicalIdx + 2], q[ancIdx]);

  Measure(q[ancIdx]);

  const bool parity12 = q.creg[ancIdx];

  if (q.creg[ancIdx]) {

  const bool parity12 = Measure(q[ancIdx]);

  if (parity12) {

    // Reset anc qubit

    X(q[ancIdx]);

  }
@@ -86,8 +84,7 @@ __qpu__ void runQecCycle(qreg q) { 
__qpu__ void resetAll(qreg q) {

  for (int i = 0; i < q.size(); ++i) {

    // Reset qubits by measure + correct.

    Measure(q[i]);

    if (q.creg[i]) {

    if (Measure(q[i])) {

      X(q[i]);

    }

  }

examples/ftqc_qrt/repeat-until-success.cpp

+5 −7
Original line number Diff line number Diff line
@@ -20,16 +20,14 @@ __qpu__ void PrepareStateUsingRUS(qreg q, int maxIter) { 


    // In order to measure in the PauliX basis, changes the basis.

    H(q[1]);

    Measure(q[1]);

    bool outcome = q.creg[1];

    if (!outcome) {

    if (!Measure(q[1])) {

      // Success (until (outcome == Zero))

      std::cout << "Success after " << i + 1 << " iterations.\n";

      break;

    } 

    // Fix up: Bring the auxiliary and target qubits back to |+> state.

    if (outcome) {

    else {

      // Measure 1: |1> state

      // Fix up: Bring the auxiliary and target qubits back to |+> state.

      X(q[1]);

      H(q[1]);

      X(q[0]);

examples/ftqc_qrt/simple-demo.cpp

+5 −5
Original line number Diff line number Diff line
@@ -10,18 +10,18 @@ __qpu__ void bell(qreg q, int nbRuns) { 
  for (int i = 0; i < nbRuns; ++i) {

    H(q[0]);

    CX(q[0], q[1]);

    Measure(q[0]);

    Measure(q[1]);

    if (q.creg[0] == q.creg[1]) {

    const bool q0Result = Measure(q[0]);

    const bool q1Result = Measure(q[1]);

    if (q0Result == q1Result) {

      std::cout << "Iter " << i << ": Matched!\n";

    } else {

      std::cout << "Iter " << i << ": NOT Matched!\n";

    }

    // Reset qubits

    if (q.creg[0]) {

    if (q0Result) {

      X(q[0]);

    }

    if (q.creg[1]) {

    if (q1Result) {

      X(q[1]);

    }

  }

handlers/token_collector/xasm/xasm_single_visitor.hpp

+22 −0
Original line number Diff line number Diff line
@@ -181,6 +181,28 @@ public: 
          ss << c->getText() << " ";

        }

      }

    } else if (context->getText().find("Measure") != std::string::npos) {

      // Found measure in a classical instruction.

      // std::cout << "FOUND MEAS: " << context->getText() << "\n";

      // To be extra careful, we use search and replace to handle edge case

      // whereby `!Measure` is considered as 1 token.

      const auto replaceAll = [](std::string &s, const std::string &search,

                                 const std::string &replace) {

        for (size_t pos = 0;; pos += replace.length()) {

          pos = s.find(search, pos);

          if (pos == std::string::npos) {

            break;

          }



          s.erase(pos, search.length());

          s.insert(pos, replace);

        }

      };

      for (auto c : context->children) {

        auto origText = c->getText();

        replaceAll(origText, "Measure", " quantum::mz");

        ss << origText << " ";

      }

    } else {

      for (auto c : context->children) {

        ss << c->getText() << " ";

handlers/token_collector/xasm/xasm_token_collector.cpp

+8 −1
Original line number Diff line number Diff line
@@ -131,7 +131,14 @@ void XasmTokenCollector::collect(clang::Preprocessor &PP, 


      lines.push_back("}\n");



    } else {

    } else if (current_token.is(clang::tok::kw_else)) { 

      auto tokenStr = PP.getSpelling(current_token);

      if (Toks[i + 1].is(clang::tok::l_brace)) {

        tokenStr += " { ";

      }

      lines.push_back(tokenStr);

    }

    else {



      // here we have some general statement, so

      // search til the semi colon