Commit 2781e522 authored by Nguyen, Thien Minh's avatar Nguyen, Thien Minh
Browse files

Port FTQC VQE to standard lib 



Signed-off-by: default avatarThien Nguyen <nguyentm@ornl.gov>
parent 9b77d7ab

examples/CMakeLists.txt

+2 −1
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@@ -14,3 +14,4 @@ add_test(NAME qrt_adapt COMMAND ${CMAKE_BINARY_DIR}/qcor -c ${CMAKE_CURRENT_SOUR 
add_test(NAME qrt_ftqc_simple COMMAND ${CMAKE_BINARY_DIR}/qcor -c -qrt ftqc ${CMAKE_CURRENT_SOURCE_DIR}/ftqc_qrt/simple-demo.cpp)

add_test(NAME qrt_ftqc_rus COMMAND ${CMAKE_BINARY_DIR}/qcor -c -qrt ftqc ${CMAKE_CURRENT_SOURCE_DIR}/ftqc_qrt/repeat-until-success.cpp)

add_test(NAME qrt_ftqc_qec COMMAND ${CMAKE_BINARY_DIR}/qcor -c -qrt ftqc ${CMAKE_CURRENT_SOURCE_DIR}/ftqc_qrt/bit-flip-code.cpp)

add_test(NAME qrt_ftqc_deuteron COMMAND ${CMAKE_BINARY_DIR}/qcor -c -qrt ftqc ${CMAKE_CURRENT_SOURCE_DIR}/ftqc_qrt/deuteron.cpp)
 
 No newline at end of file

examples/ftqc_qrt/deuteron.cpp

+4 −7
Original line number Diff line number Diff line 
#include "ftqc/vqe.hpp"

#include "xacc.hpp"

#include <qcor_vqe>



// Compile with:

// qcor -qpu qpp -qrt ftqc -I<qcor/examples/shared> deuteron.cpp 

// qcor -qpu qpp -qrt ftqc deuteron.cpp 



__qpu__ void ansatz(qreg q, double theta) {

  X(q[0]);
@@ -15,10 +16,6 @@ int main(int argc, char **argv) { 
  // Hamiltonian

  auto H = 5.907 - 2.1433 * X(0) * X(1) - 2.1433 * Y(0) * Y(1) + .21829 * Z(0) -

           6.125 * Z(1);

  // TODO:

  // We can hook this up to the QCOR's Objective function

  // The amount of code to manually instantiate the optimization loop here is

  // also very minimal.

  auto optimizer = createOptimizer("nlopt");

  xacc::OptFunction f(

      [&](const std::vector<double> &x, std::vector<double> &dx) {
@@ -26,7 +23,7 @@ int main(int argc, char **argv) { 
        auto statePrep =

            std::function<void(qreg)>{[angle](qreg q) { ansatz(q, angle); }};

        double energy = 0.0;

        EstimateEnergy(q, statePrep, H, 1024, energy);

        ftqc::estimate_energy(q, statePrep, H, 1024, energy);

        std::cout << "Energy(" << angle << ") = " << energy << "\n";

        return energy;

      },

examples/shared/ftqc/vqe.hpp→lib/impl/vqe.hpp

+19 −11
Original line number Diff line number Diff line
@@ -4,7 +4,13 @@ 
#include "qcor_observable.hpp"

#include <qcor_common>



__qpu__ void EstimateTermExpectation(qreg q, const std::function<void(qreg)>& statePrep, std::vector<qcor::PauliOperator> bases, int nSamples, double& out_energy) {



#ifdef _QCOR_FTQC_RUNTIME

namespace ftqc {

__qpu__ void estimate_term_expectation(qreg q,

                                     const std::function<void(qreg)> &statePrep,

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

                                     int nSamples, double &out_energy) {

  double sum = 0.0;

  for (int i = 0; i < nSamples; ++i) {

    statePrep(q);
@@ -20,8 +26,8 @@ __qpu__ void EstimateTermExpectation(qreg q, const std::function<void(qreg)>& st 
  out_energy = sum / nSamples;

}



// Estimates the energy of a Pauli observable by summing the energy contributed by the individual terms.

// Input:

// Estimates the energy of a Pauli observable by summing the energy contributed

// by the individual terms. Input:

// - observable

// The Pauli Hamiltonian.

// - nSamples
@@ -29,7 +35,9 @@ __qpu__ void EstimateTermExpectation(qreg q, const std::function<void(qreg)>& st 
//

// Output

// The estimated energy of the observable

__qpu__ void EstimateEnergy(qreg q, const std::function<void(qreg)>& statePrep, qcor::PauliOperator observable, int nSamples, double& out_energy) {

__qpu__ void estimate_energy(qreg q, const std::function<void(qreg)> &statePrep,

                            qcor::PauliOperator observable, int nSamples,

                            double &out_energy) {

  std::complex<double> energy = 0.0;

  for (auto &[termStr, pauliInst] : observable.getTerms()) {

    auto coeff = pauliInst.coeff();
@@ -48,14 +56,14 @@ __qpu__ void EstimateEnergy(qreg q, const std::function<void(qreg)>& statePrep, 
    }

    if (!ops.empty()) {

      double termEnergy = 0.0;

      EstimateTermExpectation(q, statePrep, ops, nSamples, termEnergy);

      estimate_term_expectation(q, statePrep, ops, nSamples, termEnergy);

      energy = energy + (coeff * termEnergy);

    }

    else {

    } else {

      // Identity term:

      energy = energy + coeff;

    }

  }

  out_energy = energy.real();

}

} // namespace ftqc

#endif

lib/qcor_vqe

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+2 −0
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#pragma once

#include "impl/vqe.hpp"