Commit 7c9e8126 authored by Mccaskey, Alex's avatar Mccaskey, Alex
Browse files

adding observe method to python qjit 



Signed-off-by: Mccaskey, Alex's avatarAlex McCaskey <mccaskeyaj@ornl.gov>
parent cec804e2

python/py-qcor.cpp

+9 −0
Original line number Diff line number Diff line
@@ -369,6 +369,15 @@ PYBIND11_MODULE(_pyqcor, m) { 
      },

      "");



  m.def(

      "internal_observe",

      [](std::shared_ptr<CompositeInstruction> kernel,

         qcor::PauliOperator &obs) {

        auto q = ::qalloc(obs.nBits());

        return qcor::observe(kernel, obs, q);

      },

      "");



  // qsim sub-module bindings:

  {

    py::module qsim = m.def_submodule("qsim", "QCOR's python qsim submodule");

python/qcor.py

+9 −1
Original line number Diff line number Diff line
@@ -268,9 +268,17 @@ class qjit(object): 
        args_dict = {}

        for i, arg_name in enumerate(self.arg_names):

            args_dict[arg_name] = list(args)[i]



        return self._qjit.extract_composite(self.function.__name__, args_dict)



    def observe(self, observable, *args):

        """

        Return the expectation value of <observable> with 

        respect to the state given by this qjit kernel evaluated 

        at the given arguments. 

        """

        program = self.extract_composite(*args)

        return internal_observe(program, observable)



    def openqasm(self, *args):

        """

        Return an OpenQasm string representation of this

python/tests/test_qcor_spec_api.py

+22 −0
Original line number Diff line number Diff line
@@ -50,6 +50,28 @@ class TestVQEObjectiveFunction(unittest.TestCase): 
        self.assertAlmostEqual(results[0], -1.74, places=1)

        print(results)



    def test_observe(self):

        H = -2.1433 * X(0) * X(1) - 2.1433 * \

            Y(0) * Y(1) + .21829 * Z(0) - 6.125 * Z(1) + 5.907



        @qjit

        def ansatz(q : qreg, theta : float):

            X(q[0])

            Ry(q[1], theta)

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



        target_energy = -1.74



        def objective_function(x):

            q = qalloc(H.nBits())

            energy = ansatz.observe(H, q, x[0])

            return abs(target_energy - energy)



        optimizer = createOptimizer('nlopt', {'nlopt-maxeval':20})

        opt_val, opt_params = optimizer.optimize(objective_function, 1)   

        self.assertAlmostEqual(opt_val, 0.0, places=1)

        self.assertAlmostEqual(opt_params[0], .5, places=1)





if __name__ == '__main__':

    unittest.main()