Commit ddf7d0d9 authored by Nguyen, Thien Minh's avatar Nguyen, Thien Minh
Browse files

Start working on QEC std lib 



Signed-off-by: default avatarThien Nguyen <nguyentm@ornl.gov>
parent 3e2e0690

examples/ftqc_qrt/error_correcting_code.cpp

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#include <qcor_qec>



int main() {

  auto q = qalloc(4);

  bit_flip_encoder(q, 0, {1, 2});

}
 
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lib/impl/bit_flip_code.hpp

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#pragma once

#include <qcor_common>



__qpu__ void bit_flip_encoder(qreg q, int dataQubitIdx,

                              std::vector<int> scratchQubitIdx) {

  CX(q[dataQubitIdx], q[scratchQubitIdx[0]]);

  CX(q[dataQubitIdx], q[scratchQubitIdx[1]]);

}



#ifdef _QCOR_FTQC_RUNTIME

namespace ftqc {

__qpu__ void measure_stabilizer_generators(

    qreg q, std::vector<std::vector<qcor::PauliOperator>> stabilizerGroup,

    std::vector<int> logicalReg, int scratchQubitIdx,

    std::vector<int> &out_syndromes) {

  for (auto &stabilizer : stabilizerGroup) {

    for(auto &op : stabilizer) {

      // TODO: generalize for all codes

      std::map<int, int> bitMap;

      bitMap[0] = logicalReg[0];

      bitMap[1] = logicalReg[1];

      bitMap[2] = logicalReg[2];

      op.mapQubitSites(bitMap);

    }

    int syndromeResult;

    measure_basis_with_scratch(q, scratchQubitIdx, stabilizer, syndromeResult);

    out_syndromes.emplace_back(syndromeResult);

  }

}

} // namespace ftqc

#endif
 
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lib/impl/common.hpp

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@@ -35,5 +35,37 @@ __qpu__ void measure_basis(qreg q, std::vector<qcor::PauliOperator> bases, 
  }

  out_parity = oneCount - 2 * (oneCount / 2);

}



// Measure the given Pauli operator using an explicit scratch qubit to perform the measurement.

__qpu__ void measure_basis_with_scratch(qreg q, int scratchQubit,

                                        std::vector<qcor::PauliOperator> bases,

                                        int &out_result) {

  H(q[scratchQubit]);

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

    auto pauliOp = bases[i];

    const std::string pauliStr = pauliOp.toString().substr(6);

    const auto bitIdx = std::stoi(pauliStr.substr(1));

    // Pauli-X

    if (pauliStr.rfind("X", 0) == 0) {

      CX(q[scratchQubit], q[bitIdx]);

    }

    // Pauli-Y

    if (pauliStr.rfind("Y", 0) == 0) {

      CY(q[scratchQubit], q[bitIdx]);

    }

    // Pauli-Z

    if (pauliStr.rfind("Z", 0) == 0) {

      CZ(q[scratchQubit], q[bitIdx]);

    }

  }

  H(q[scratchQubit]);

  if (Measure(q[scratchQubit])) {

    out_result = 1;

    // Reset scratchQubit as well

    X(q[scratchQubit]);

  } else {

    out_result = 0;

  }

}

} // namespace ftqc

#endif
 
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lib/qcor_qec

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#pragma once

#include "impl/bit_flip_code.hpp"