Commit 90f18cd9 authored by Nguyen, Thien Minh's avatar Nguyen, Thien Minh
Browse files

Compute the whole deuteron expectation in Q# 



Signed-off-by: default avatarThien Nguyen <nguyentm@ornl.gov>
parent 1de31581

examples/qsharp/FTQC/VQE/vqe_ansatz.qs

+92 −17
Original line number Diff line number Diff line
@@ -6,6 +6,8 @@ open QCOR.Intrinsic; 
// Note: parameter initialization is done here.

// Returns the final energy.

operation DeuteronVqe(shots: Int, stepper : ((Double, Double[]) => Double[])) : Double {

    // Deuteron Hamiltonian:

    // H = "5.907 - 2.1433 X0X1 - 2.1433 Y0Y1 + .21829 Z0 - 6.125 Z1");

    // Stopping conditions:

    let max_iters = 10;

    let f_tol = 0.01;
@@ -16,10 +18,27 @@ operation DeuteronVqe(shots: Int, stepper : ((Double, Double[]) => Double[])) : 
    use qubits = Qubit[2]

    {

        for iter_id in 1..max_iters {

            let xxExp = DeuteronXX(qubits, shots, opt_params[0]);

            let yyExp = DeuteronYY(qubits, shots, opt_params[0]);

            let z0Exp = DeuteronZ0(qubits, shots, opt_params[0]);

            let z1Exp = DeuteronZ1(qubits, shots, opt_params[0]);

            set energy_val = 5.907 - 2.1433 * xxExp - 2.1433 * yyExp + 0.21829 * z0Exp - 6.125 * z1Exp;

            // Stepping...

            set opt_params = stepper(energy_val, opt_params);

        } 

    }

    // Final energy:

    return energy_val;

}



// This is for testing only:

// We should use a nicer implementation...

// XX term

operation DeuteronXX(qubits: Qubit[], shots: Int, theta: Double) : Double {

    mutable numParityOnes = 0;

            for test in 1..shots {

    for shot in 1..shots {

        X(qubits[0]);

                Ry(opt_params[0], qubits[1]);

        Ry(theta, qubits[1]);

        CNOT(qubits[1], qubits[0]);

        // Let's measure <X0X1>

        H(qubits[0]);
@@ -31,13 +50,69 @@ operation DeuteronVqe(shots: Int, stepper : ((Double, Double[]) => Double[])) : 
        Reset(qubits[0]);

        Reset(qubits[1]);

    }

            set energy_val =  IntAsDouble(shots - numParityOnes)/IntAsDouble(shots) - IntAsDouble(numParityOnes)/IntAsDouble(shots);

            // Stepping...

            set opt_params = stepper(energy_val, opt_params);

    

    let exp_val =  IntAsDouble(shots - numParityOnes)/IntAsDouble(shots) - IntAsDouble(numParityOnes)/IntAsDouble(shots);

    return exp_val;

}



// YY term

operation DeuteronYY(qubits: Qubit[], shots: Int, theta: Double) : Double {

    mutable numParityOnes = 0;

    for shot in 1..shots {

        X(qubits[0]);

        Ry(theta, qubits[1]);

        CNOT(qubits[1], qubits[0]);

        // Let's measure <Y0Y1>

        Rx(1.57079632679, qubits[0]);

        Rx(1.57079632679, qubits[1]);

        if M(qubits[0]) != M(qubits[1]) 

        {

            set numParityOnes += 1;

        }

        Reset(qubits[0]);

        Reset(qubits[1]);

    }

    

    // Final energy:

    return energy_val;

    let exp_val =  IntAsDouble(shots - numParityOnes)/IntAsDouble(shots) - IntAsDouble(numParityOnes)/IntAsDouble(shots);

    return exp_val;

}



// Z0 term

operation DeuteronZ0(qubits: Qubit[], shots: Int, theta: Double) : Double {

    mutable numParityOnes = 0;

    for shot in 1..shots {

        X(qubits[0]);

        Ry(theta, qubits[1]);

        CNOT(qubits[1], qubits[0]);

        if M(qubits[0]) == One

        {

            set numParityOnes += 1;

        }

        Reset(qubits[0]);

        Reset(qubits[1]);

    }

    

    let exp_val =  IntAsDouble(shots - numParityOnes)/IntAsDouble(shots) - IntAsDouble(numParityOnes)/IntAsDouble(shots);

    return exp_val;

}





// Z1 term

operation DeuteronZ1(qubits: Qubit[], shots: Int, theta: Double) : Double {

    mutable numParityOnes = 0;

    for shot in 1..shots {

        X(qubits[0]);

        Ry(theta, qubits[1]);

        CNOT(qubits[1], qubits[0]);

        if M(qubits[1]) == One

        {

            set numParityOnes += 1;

        }

        Reset(qubits[0]);

        Reset(qubits[1]);

    }

    

    let exp_val =  IntAsDouble(shots - numParityOnes)/IntAsDouble(shots) - IntAsDouble(numParityOnes)/IntAsDouble(shots);

    return exp_val;

}

}
 
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