Commit afccb2df authored by Mccaskey, Alex's avatar Mccaskey, Alex
Browse files

adding as_unitary_matrix() to c++ QuantumKernel 



Signed-off-by: Mccaskey, Alex's avatarAlex McCaskey <mccaskeyaj@ornl.gov>
parent 89528309

examples/deuteron/as_unitary.cpp

0 → 100644
+29 −0
Original line number Diff line number Diff line 


__qpu__ void ansatz(qreg q, double x) {

  X(q[0]);

  Ry(q[1], x);

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

}



int main() {

  auto q = qalloc(2);



  // Map the ansatz to a unitary matrix

  UnitaryMatrix u_mat = ansatz::as_unitary_matrix(q, .59);



  // Create the Hamiltonian, map to a DenseMatrix (complex values)

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

           6.125 * Z(1) + 5.907;

  DenseMatrix Hmat = get_dense_matrix(H);



  // Create the initial |0> state

  DenseVector init_state = DenseVector::Zero(4);

  init_state(0) = 1.;



  // Compute |psi> = U |0>

  DenseVector final_state = u_mat * init_state;



  // Compute the energy E = <psi | H | psi>

  std::complex<double> energy = final_state.transpose() * Hmat * final_state;

  std::cout << energy.real() << "\n";

}

runtime/kernel/quantum_kernel.hpp

+23 −7
Original line number Diff line number Diff line
@@ -30,7 +30,8 @@ enum class QrtType { NISQ, FTQC }; 
// with an appropriate implementation of constructors and destructors.

// Users can then call for adjoint/ctrl methods like this

// foo::adjoint(q); foo::ctrl(1, q);

template <typename Derived, typename... Args> class QuantumKernel {

template <typename Derived, typename... Args>

class QuantumKernel {

 protected:

  // Tuple holder for variadic kernel arguments

  std::tuple<Args...> args_tuple;
@@ -63,7 +64,8 @@ public: 
  QuantumKernel(std::shared_ptr<qcor::CompositeInstruction> _parent_kernel,

                Args... args)

      : args_tuple(std::forward_as_tuple(args...)),

        parent_kernel(_parent_kernel), is_callable(false) {

        parent_kernel(_parent_kernel),

        is_callable(false) {

    runtime_env = (__qrt_env == "ftqc") ? QrtType::FTQC : QrtType::NISQ;

  }
@@ -87,7 +89,6 @@ public: 
  // Create the Adjoint of this quantum kernel

  static void adjoint(std::shared_ptr<CompositeInstruction> parent_kernel,

                      Args... args) {



    // instantiate and don't let it call the destructor

    Derived derived(args...);

    derived.disable_destructor = true;
@@ -170,7 +171,6 @@ public: 
  // Create the controlled version of this quantum kernel

  static void ctrl(std::shared_ptr<CompositeInstruction> parent_kernel,

                   qubit ctrl_qbit, Args... args) {



    int ctrl_bit = (int)ctrl_qbit.second;



    // instantiate and don't let it call the destructor
@@ -197,6 +197,22 @@ public: 
    // Need to reset and point current program to the parent

    quantum::set_current_program(parent_kernel);

  }



  static Eigen::MatrixXcd as_unitary_matrix(Args... args) {

    Derived derived(args...);

    derived.disable_destructor = true;

    derived(args...);

    qcor::KernelToUnitaryVisitor visitor(derived.parent_kernel->nLogicalBits());

    xacc::InstructionIterator iter(derived.parent_kernel);

    while (iter.hasNext()) {

      auto inst = iter.next();

      if (!inst->isComposite() && inst->isEnabled()) {

        inst->accept(&visitor);

      }

    }

    return visitor.getMat();

  }



  virtual ~QuantumKernel() {}

};

runtime/observable/qcor_observable.cpp

+21 −0
Original line number Diff line number Diff line
@@ -48,6 +48,27 @@ PauliOperator SM(int idx) { 
  std::complex<double> imag(0.0, 1.0);

  return X(idx) - imag * Y(idx);

}



Eigen::MatrixXcd get_dense_matrix(PauliOperator &op) {

  auto mat_el = op.to_sparse_matrix();

  auto size = std::pow(2, op.nBits());

  Eigen::MatrixXcd mat = Eigen::MatrixXcd::Zero(size, size);

  for (auto el : mat_el) {

    mat(el.row(), el.col()) = el.coeff();

  }

  return mat;

}



Eigen::MatrixXcd get_dense_matrix(std::shared_ptr<Observable> op) {

  auto mat_el = op->to_sparse_matrix();

  auto size = std::pow(2, op->nBits());

  Eigen::MatrixXcd mat = Eigen::MatrixXcd::Zero(size, size);

  for (auto el : mat_el) {

    mat(el.row(), el.col()) = el.coeff();

  }

  return mat;

}



std::shared_ptr<xacc::Observable> createObservable(const std::string &repr) {

  if (!xacc::isInitialized())

    xacc::internal_compiler::compiler_InitializeXACC();

runtime/observable/qcor_observable.hpp

+4 −0
Original line number Diff line number Diff line
@@ -30,6 +30,10 @@ PauliOperator operator+(PauliOperator &op, double coeff); 
PauliOperator operator-(double coeff, PauliOperator &op);

PauliOperator operator-(PauliOperator &op, double coeff);





Eigen::MatrixXcd get_dense_matrix(PauliOperator &op);

Eigen::MatrixXcd get_dense_matrix(std::shared_ptr<Observable> op);



// Public observe function, returns expected value of Observable

template <typename... Args>

auto observe(void (*quantum_kernel_functor)(

runtime/utils/qcor_utils.cpp

+1 −0
Original line number Diff line number Diff line
@@ -99,6 +99,7 @@ std::shared_ptr<qcor::CompositeInstruction> decompose_unitary( 
}



}  // namespace __internal__



using namespace xacc::quantum;



MatrixXcd X_Mat{MatrixXcd::Zero(2, 2)};