adding compute action uncompute example

__qpu__ void hf(qreg q) {

  X(q[0]);

  X(q[2]);

}

__qpu__ void ucc1(qreg q, double x) {

  // The following syntax gives us

  // U V Udag functionality. This provides

  // the familia ProjectQ / Q# / etc.

  // compute - action - uncompute

  compute {

    Rx(q[0], constants::pi / 2);

    for (auto i : range(3)) H(q[i + 1]);

    for (auto i : range(3)) {

      CX(q[i], q[i + 1]);

    }

  }

  action { Rz(q[3], x); }

}

__qpu__ void ansatz(qreg q, double x) {

  hf(q);

  ucc1(q, x);

}

__qpu__ void test_ctrl(qreg q, double d) { ucc1::ctrl(q[4], q, d); }

int main() {

  auto H = createOperator(

      "pyscf", {{"basis", "sto-3g"}, {"geometry", R"#(H  0.000000   0.0      0.0

H   0.0        0.0  .7474)#"}});

  auto objective = createObjectiveFunction(ansatz, H, 1);

  auto optimizer = createOptimizer("nlopt", {{"maxeval", 20}});

  // Optimize the above function

  auto [optval, opt_params] = optimizer->optimize(*objective.get());

  // Print the result

  printf("energy = %f\n", optval);

  ansatz::print_kernel(std::cout, qalloc(4), 2.2);

  // Should only see CRZ, U, Udag should be uncontrolled

  auto qq = qalloc(5);

  test_ctrl::print_kernel(std::cout, qq, 2.2);

}

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