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use float_cmp::ApproxEqUlps;
use complex::Complex;
use gate::Gate;
use matrix::MAX_SIZE;
use registers::ClassicalRegister;
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct Ket {
size: usize,
pub elements: [Complex; MAX_SIZE],
}
impl Ket {
pub fn new(size: usize) -> Ket {
Ket {
size: size,
elements: [Complex::zero(); MAX_SIZE],
}
}
pub fn from_classical(register: &ClassicalRegister) -> Ket {
let mut ket = Ket::new(Ket::size(register.width()));
ket.elements[register.state() as usize] = Complex::one();
ket
}
#[allow(unused)]
pub fn is_valid(&self) -> bool {
let mut sample_space_sum = 0f64;
for coefficient in self.elements.iter() {
sample_space_sum += coefficient.norm_sqr()
}
sample_space_sum.approx_eq_ulps(&1.0f64, 10)
}
#[allow(unused)]
pub fn is_classical(&self) -> bool {
assert!(self.is_valid());
let mut zeroes = 0;
let mut ones = 0;
let mut others = 0;
for coefficient in self.elements.iter() {
if Complex::zero() == *coefficient {
zeroes += 1;
} else if Complex::one() == *coefficient {
ones += 1;
} else {
others += 1;
}
}
return 1 == ones && 0 == others;
}
pub fn size(register_width: usize) -> usize {
2usize.pow(register_width as u32)
}
pub fn apply(&mut self, gate: Gate) {
self.elements = gate.matrix() * &self.elements;
}
}
#[test]
fn valid_test() {
let mut valid = Ket::new(3);
valid.elements[0] = Complex::zero();
valid.elements[1] = Complex::zero();
valid.elements[2] = Complex::one();
let mut invalid = Ket::new(3);
invalid.elements[0] = Complex::new(0.5, 0.0);
invalid.elements[1] = Complex::new(0.0, 0.5);
assert!(valid.is_valid());
assert_eq!(false, invalid.is_valid());
}
#[test]
fn classical_test() {
let sqrt2inv = 2.0f64.sqrt().recip();
let mut classical = Ket::new(3);
classical.elements[0] = Complex::zero();
classical.elements[1] = Complex::zero();
classical.elements[2] = Complex::one();
let mut nonclassical1 = Ket::new(2);
nonclassical1.elements[0] = Complex::new(sqrt2inv, 0.0);
nonclassical1.elements[1] = Complex::new(0.0, sqrt2inv);
let mut nonclassical2 = Ket::new(2);
nonclassical2.elements[0] = Complex::new(0.5, 0.5);
nonclassical2.elements[1] = Complex::new(0.5, 0.5);
assert!(classical.is_classical());
assert_eq!(false, nonclassical1.is_classical());
assert_eq!(false, nonclassical2.is_classical());
}
#[test]
fn from_classical_test() {
let r: ClassicalRegister = ClassicalRegister::new(vec![0, 1]);
let mut expected = Ket::new(4);
expected.elements[0] = Complex::zero();
expected.elements[1] = Complex::zero();
expected.elements[2] = Complex::one();
expected.elements[3] = Complex::zero();
assert!(Ket::from_classical(&r).is_classical());
assert_eq!(expected, Ket::from_classical(&r));
}