Simple binding for kernel autograd (aea38287) · Commits · ORNL Quantum Computing Institute / qcor

python/py-qcor.cpp

+29 −0

Original line number	Diff line number	Diff line
		@@ -743,6 +743,35 @@ PYBIND11_MODULE(_pyqcor, m) {
		return qcor::observe(kernel, observable, q);
		},
		"");
		m.def(
		"internal_autograd",
		[](py::function &kernel_eval, qcor::PauliOperator &obs,
		std::vector<double> x) -> std::tuple<double, std::vector<double>> {
		try {
		std::function<std::shared_ptr<xacc::CompositeInstruction>(
		std::vector<double>)>
		cpp_kernel_eval = [&](std::vector<double> x_vec) {
		auto ret = kernel_eval(x_vec);
		auto kernel = ret.cast<std::shared_ptr<CompositeInstruction>>();
		return kernel;
		};

		auto gradiend_method = qcor::__internal__::get_gradient_method(
		qcor::__internal__::DEFAULT_GRADIENT_METHOD, cpp_kernel_eval,
		obs);

		auto program = cpp_kernel_eval(x);
		auto q = ::qalloc(
		std::max((int)obs.nBits(), (int)program->nPhysicalBits()));
		auto cost_val = qcor::observe(program, obs, q);
		auto dx = (*gradiend_method)(x, cost_val);
		return std::make_tuple(cost_val, dx);
		} catch (std::exception &e) {
		qcor::error("Invalid kernel evaluator.");
		return std::make_tuple(0.0, std::vector<double>{});
		}
		},
		"");

		m.def("internal_get_all_instructions", []() -> std::vector<py::tuple> {
		auto insts = xacc::getServices<xacc::Instruction>();

+15 −0

Original line number	Diff line number	Diff line
		@@ -606,6 +606,21 @@ class qjit(object):
		program = self.extract_composite(*args)
		return internal_observe(program, observable)

		def autograd(self, observable, qreg, x_vec):
		"""
		Return the expectation value and gradients of <observable> with
		respect to the state given by this qjit kernel evaluated
		at the given arguments.
		"""
		def kernel_eval(x):
		program = self.extract_composite(qreg, x)
		return program

		if isinstance(x_vec, float):
		x_vec = [x_vec]

		return internal_autograd(kernel_eval, observable, x_vec)

		def openqasm(self, *args):
		"""
		Return an OpenQasm string representation of this

+7 −1

Original line number	Diff line number	Diff line
		@@ -88,3 +88,9 @@ add_test (NAME qcor_python_bug_89
		set_tests_properties(qcor_python_bug_89
		PROPERTIES ENVIRONMENT "PYTHONPATH=${CMAKE_INSTALL_PREFIX}:$ENV{PYTHONPATH}")

		add_test (NAME qcor_python_kernel_autograd
		COMMAND ${Python_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/test_autograd_opt.py
		WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
		)
		set_tests_properties(qcor_python_kernel_autograd
		PROPERTIES ENVIRONMENT "PYTHONPATH=${CMAKE_INSTALL_PREFIX}:$ENV{PYTHONPATH}")
		No newline at end of file

0 → 100644

+30 −0

Original line number	Diff line number	Diff line
		import faulthandler
		faulthandler.enable()

		import unittest
		from qcor import *

		class TestQCORKernelAutoGrad(unittest.TestCase):
		def test_simple_deuteron(self):
		@qjit
		def ansatz1(q: qreg, theta: List[float]):
		X(q[0])
		Ry(q[1], theta[0])
		CX(q[1], q[0])

		q = qalloc(2)
		H = -2.1433 * X(0) * X(1) - 2.1433 * \
		Y(0) * Y(1) + .21829 * Z(0) - 6.125 * Z(1) + 5.907

		def objective_function(x):
		q = qalloc(2)
		return ansatz1.autograd(H, q, x)

		optimizer = createOptimizer('nlopt', {'algorithm':'l-bfgs'})
		(energy, opt_params) = optimizer.optimize(objective_function, 1)
		print("Energy =", energy)
		print("Opt params =", opt_params)
		self.assertAlmostEqual(energy, -1.74886, places=1)

		if __name__ == '__main__':
		unittest.main()