QFT part 4: Using R1 gate, instead of S and T.

Since I do want to extend the number of qubits from three to more, I have re-written the code with R1 gate, in stead of S and T.

Lessons learned: Functions and operations can be defined. Here a function which returns Double is created. Operations might be used for qubits. Not sure now.

namespace QFT_naive {

open Microsoft.Quantum.Canon;

open Microsoft.Quantum.Intrinsic;

open Microsoft.Quantum.Convert;

open Microsoft.Quantum.Arrays;

open Microsoft.Quantum.Measurement;

open Microsoft.Quantum.Math;

@EntryPoint()

operation SayHello() : Unit {

mutable counts = new Int[8];

let theta_1 = calcTheta(1.0);

let theta_2 = calcTheta(2.0);

let theta_3 = calcTheta(3.0);

for trian in 1..1000 {

use input = Qubit[3] {

// 1/sqrt(8) (|000> + |001> + ,,, + |111>)

H(input[0]);

H(input[1]);

H(input[2]);

// Star QFT

// R1 = Z, R2=S, R3=T

H(input[0]);

//(Controlled S)([input[1]],input[0]);

//(Controlled T)([input[2]],input[0]);

(Controlled R1)([input[1]],(theta_2,input[0]));

(Controlled R1)([input[2]],(theta_3,input[0]));

H(input[1]);

//(Controlled S)([input[2]],input[1]);

(Controlled R1)([input[2]],(theta_2,input[1]));

H(input[2]);

SWAP(input[2],input[0]);

let res = MultiM(input);

let bit = ResultArrayAsInt(res);

set counts w/= bit <- counts[bit]+ 1;

ResetAll(input);

}

}

for j in 0..7 {

Message(IntAsString(counts[j]));

}

}

function calcTheta(l : Double) : Double {

return 2.0*PI()/(PowD(2.0,l));

}

}