Commit 9374de14 authored by Nguyen, Thien Minh's avatar Nguyen, Thien Minh
Browse files

Optimize qrt exp function 



Trying to follow the xasm str construction to make sure we don't introduce bugs.

Signed-off-by: default avatarThien Nguyen <nguyentm@ornl.gov>
parent 46b17eda

runtime/qrt/impls/nisq/nisq_qrt.cpp

+28 −39
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include "xacc_internal_compiler.hpp"

#include "xacc_observable.hpp"

#include "xacc_service.hpp"

#include "CommonGates.hpp"



using namespace cppmicroservices;

using namespace xacc;
@@ -173,7 +174,7 @@ class NISQ : public ::quantum::QuantumRuntime { 


    double pi = xacc::constants::pi;

    auto gateRegistry = xacc::getIRProvider("quantum");

    std::string xasm_src = "";

    std::vector<xacc::InstPtr> exp_insts;



    auto q_name = q.name();

    for (auto inst : terms) {
@@ -192,7 +193,7 @@ class NISQ : public ::quantum::QuantumRuntime { 
      int largestQbitIdx = terms[terms.size() - 1].first;



      std::vector<std::size_t> qidxs;

      std::stringstream basis_front, basis_back;

      std::vector<xacc::InstPtr> basis_front, basis_back;



      for (auto &term : terms) {

        auto qid = term.first;
@@ -201,14 +202,11 @@ class NISQ : public ::quantum::QuantumRuntime { 
        qidxs.push_back(qid);



        if (pop == "X") {

          basis_front << "H(" << q_name << "[" << qid << "]);\n";

          basis_back << "H(" << q_name << "[" << qid << "]);\n";



          basis_front.emplace_back(std::make_shared<xacc::quantum::Hadamard>(qid));

          basis_back.emplace_back(std::make_shared<xacc::quantum::Hadamard>(qid));

        } else if (pop == "Y") {

          basis_front << "Rx(" << q_name << "[" << qid << "], " << 1.57079362679

                      << ");\n";

          basis_back << "Rx(" << q_name << "[" << qid << "], " << -1.57079362679

                     << ");\n";

          basis_front.emplace_back(std::make_shared<xacc::quantum::Rx>(qid, 1.57079362679));

          basis_back.emplace_back(std::make_shared<xacc::quantum::Rx>(qid, -1.57079362679));

        }

      }
@@ -223,54 +221,45 @@ class NISQ : public ::quantum::QuantumRuntime { 
      }



      // std::cout << "HOWDY: \n" << cnot_pairs << "\n";

      std::stringstream cnot_front, cnot_back;

      std::vector<xacc::InstPtr> cnot_front, cnot_back;

      for (int i = 0; i < qidxs.size() - 1; i++) {

        Eigen::VectorXi pairs = cnot_pairs.col(i);

        auto c = pairs(0);

        auto t = pairs(1);

        cnot_front << "CNOT(" << q_name << "[" << c << "], " << q_name << "["

                   << t << "]);\n";

        cnot_front.emplace_back(std::make_shared<xacc::quantum::CNOT>(c, t));

      }



      for (int i = qidxs.size() - 2; i >= 0; i--) {

        Eigen::VectorXi pairs = cnot_pairs.col(i);

        auto c = pairs(0);

        auto t = pairs(1);

        cnot_back << "CNOT(" << q_name << "[" << c << "], " << q_name << "["

                  << t << "]);\n";

        cnot_back.emplace_back(std::make_shared<xacc::quantum::CNOT>(c, t));

      }



      xasm_src = xasm_src + "\n" + basis_front.str() + cnot_front.str();

      exp_insts.insert(exp_insts.end(),

                       std::make_move_iterator(basis_front.begin()),

                       std::make_move_iterator(basis_front.end()));

      exp_insts.insert(exp_insts.end(),

                       std::make_move_iterator(cnot_front.begin()),

                       std::make_move_iterator(cnot_front.end()));



      // FIXME, we assume real coefficients, if its zero,

      // check that the imag part is not zero and use it

      if (std::fabs(std::real(spinInst.coeff())) > 1e-12) {

        xasm_src = xasm_src + "Rz(" + q_name + "[" +

                   std::to_string(qidxs[qidxs.size() - 1]) + "], " +

                   std::to_string(std::real(spinInst.coeff()) * theta) + ");\n";

        exp_insts.emplace_back(std::make_shared<xacc::quantum::Rz>(

            qidxs[qidxs.size() - 1], std::real(spinInst.coeff()) * theta));

      } else if (std::fabs(std::imag(spinInst.coeff())) > 1e-12) {

        xasm_src = xasm_src + "Rz(" + q_name + "[" +

                   std::to_string(qidxs[qidxs.size() - 1]) + "], " +

                   std::to_string(std::imag(spinInst.coeff()) * theta) + ");\n";

      }



      xasm_src = xasm_src + cnot_back.str() + basis_back.str();

    }



    int name_counter = 1;

    std::string name = "exp_tmp";

    while (xacc::hasCompiled(name)) {

      name += std::to_string(name_counter);

    }



    xasm_src =

        "__qpu__ void " + name + "(qbit " + q_name + ") {\n" + xasm_src + "}";



    //   std::cout << "FROMQRT: " << theta << "\n" << xasm_src << "\n";

    auto xasm = xacc::getCompiler("xasm");

    auto tmp = xasm->compile(xasm_src)->getComposites()[0];



    for (auto inst : tmp->getInstructions()) {

        exp_insts.emplace_back(std::make_shared<xacc::quantum::Rz>(

            qidxs[qidxs.size() - 1], std::imag(spinInst.coeff()) * theta));

      }

      exp_insts.insert(exp_insts.end(),

                       std::make_move_iterator(cnot_back.begin()),

                       std::make_move_iterator(cnot_back.end()));

      exp_insts.insert(exp_insts.end(),

                       std::make_move_iterator(basis_back.begin()),

                       std::make_move_iterator(basis_back.end()));

    }

    for (auto& inst : exp_insts) {

      inst->setBufferNames(std::vector<std::string>(inst->bits().size(), q_name));

      program->addInstruction(inst);

    }

  }