Commit 1b6fe359 authored by Nguyen, Thien Minh's avatar Nguyen, Thien Minh
Browse files

Refactor Measure rewrite to a helper 



Also, apply Python constant rewrite and Measure result access to all classical context: If conditions and assigments.

Signed-off-by: default avatarThien Nguyen <nguyentm@ornl.gov>
parent b6a4c079

handlers/token_collector/pyxasm/pyxasm_visitor.hpp

+35 −26
Original line number Diff line number Diff line
@@ -220,7 +220,8 @@ class pyxasm_visitor : public pyxasmBaseVisitor { 
      // Handle simple assignment: a = expr

      std::stringstream ss;

      const std::string lhs = ctx->testlist_star_expr(0)->getText();

      const std::string rhs = ctx->testlist_star_expr(1)->getText();

      const std::string rhs = replacePythonConstants(

          replaceMeasureAssignment(ctx->testlist_star_expr(1)->getText()));

      ss << "auto " << lhs << " = " << rhs << "; \n";

      result.first = ss.str();

      if (rhs.find("**") != std::string::npos) {
@@ -264,31 +265,10 @@ class pyxasm_visitor : public pyxasmBaseVisitor { 
    // Only support single clause atm

    if (ctx->test().size() == 1) {

      std::stringstream ss;

      std::string ifConditionExpr = ctx->test(0)->getText();



      if (ifConditionExpr.find("Measure") != std::string::npos) {

        // Found measure in an if statement instruction.

        const auto replaceMeasureInst = [](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;

            }

            if (!isspace(s[pos + search.length()]) &&

                (s[pos + search.length()] != '(')) {

              continue;

            }

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

            s.insert(pos, replace);

          }

        };

        // Handle FTQC Measure in *if* conditional clause

        replaceMeasureInst(ifConditionExpr, "Measure", "quantum::mz");

      }



      ss << "if (" << ifConditionExpr << ") {\n";

      ss << "if ("

         << replacePythonConstants(

                replaceMeasureAssignment(ctx->test(0)->getText()))

         << ") {\n";

      result.first = ss.str();

      return 0;

    }
@@ -311,4 +291,33 @@ class pyxasm_visitor : public pyxasmBaseVisitor { 
    }

    return newSrc;

  }



  // Assignment of Measure results -> variable or in if conditional statements

  std::string replaceMeasureAssignment(const std::string &in_expr) const {

    if (in_expr.find("Measure") != std::string::npos) {

      // Found measure in an if statement instruction.

      const auto replaceMeasureInst = [](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;

          }

          if (!isspace(s[pos + search.length()]) &&

              (s[pos + search.length()] != '(')) {

            continue;

          }

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

          s.insert(pos, replace);

        }

      };



      std::string result = in_expr;

      replaceMeasureInst(result, "Measure", "quantum::mz");

      return result;

    } else {

      return in_expr;

    }

  }

};
 
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python/examples/bit_flip_code_ftqc.py

0 → 100644
+49 −0
Original line number Diff line number Diff line 
# Using QCOR FTQC runtime, which supports 

# fast feedforward of measurement results.



from qcor import qjit, qalloc, qreg



# Encode qubits into logical qubits:

# Assume q[0], q[3], q[6] are initial physical qubits

# that will be mapped to logical qubits q[0-2], q[3-5], etc.

@qjit

def encodeLogicalQubit(q : qreg):

    nbLogicalQubits = q.size() / 3

    for i in range(nbLogicalQubits):

        physicalQubitIdx = 3 * i

        CX(q[physicalQubitIdx], q[physicalQubitIdx + 1])

        CX(q[physicalQubitIdx], q[physicalQubitIdx + 2])



# Measure syndromes of a logical qubit using the provided ancilla

# Assume that the ancilla is in |0> state and must be returned in that state.

@qjit

def measureSyndrome(q : qreg, logicalIdx: int, ancIdx: int):

    physicalIdx = logicalIdx * 3

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

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

    parity01 = Measure(q[ancIdx])

    if parity01: 

        #Reset anc qubit

        X(q[ancIdx])

    

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

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

    parity12 = Measure(q[ancIdx])

    if parity12:

        #Reset anc qubit

        X(q[ancIdx])



@qjit

def testBitflipCode(q : qreg):

    H(q[0])

    encodeLogicalQubit(q)

    measureSyndrome(q, 0, 3)

    # Apply an X error

    X(q[0])

    measureSyndrome(q, 0, 3)





# Allocate 4 qubits: 3 qubits + 1 ancilla

q = qalloc(4)



testBitflipCode(q)
 
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