// single-qubit state and operations
//
#include <iostream>
#include <cmath>   // sqrt()
#include <cstdlib> // rand(), RAND_MAX
#include "Q1.h"
using namespace std;

Q1::Q1() { a0 = 1;  a1 = 0; }

void Q1::print(const char msg[]) const
{
  cout << msg << ":" << endl;
  cout << " 0  " << a0*a0 << "   (" << a0 << ")" << endl;
  cout << " 1  " << a1*a1 << "   (" << a1 << ")" << endl;
}

void Q1::X() { double t0 = a0, t1 = a1;  a0 = t1;  a1 = t0; } // NOT

int Q1::M() // measure
{
  double v, P = rand()/(RAND_MAX+1.0), R = a0*a0;

  if( P < R) { v = 0;  a0 = 1;  a1 = 0; }
  else       { v = 1;  a0 = 0;  a1 = 1; }

  return v;
}

void Q1::Z() { a1 = -a1; } // phase-flip

void Q1::H() // Hadamard
{
  double s2 = sqrt(2)/2, t0 = a0, t1 = a1;

  a0 = s2*(t0+t1);  a1 = s2*(t0-t1);
}