Examples PR 3: Grovers example

qip/examples/grovers.rs

@@ -0,0 +1,70 @@
+use qip::builder::Qudit;
+use qip::builder_traits::UnitaryBuilder;
+use qip::prelude::*;
+use std::num::NonZeroUsize;
+//-> Result<(), CircuitError>
+
+fn prepare_state<P: Precision>(n: u64) -> Result<(), CircuitError> {
+    let mut b = LocalBuilder::<f64>::default();
+
+    let n = NonZeroUsize::new(n as usize).unwrap();
+    let r = b.register(n);
+    let r = b.h(r);
+
+    let anc = b.qubit();
+    let anc = b.not(anc);
+    let anc = b.h(anc);
+
+    let r = b.merge_two_registers(r, anc);
+
+    let (_, handle) = b.measure_stochastic(r);
+
+    let (state, measures) = b.calculate_state();
+    println!("{:?}", state);
+    println!("{:?}", measures.get_stochastic_measurement(handle));
+    Ok(())
+}
+#[cfg(feature = "macros")]
+fn apply_us<P: Precision>(
+    b: &mut dyn UnitaryBuilder<P>,
+    search: Qudit,
+    ancillary: Qudit,
+    x0: u64,
+) -> Result<(Qudit, Qudit), CircuitError> {
+    let search = b.h(search);
+    let (search, ancillary) = program!(b, search, ancillary, |x| {
+        (0, if x == 0 { std::f64::consts::PI } else { 0.0 })
+    })?;
+    let search = b.h(search);
+    Ok((search, ancillary))
+}
+
+#[cfg(feature = "macros")]
+fn apply_uw(
+    b: &mut dyn UnitaryBuilder,
+    search: Qudit,
+    ancillary: Qudit,
+    x0: u64,
+) -> Result<(Qudit, Qudit), CircuitError> {
+    // Need to move the x0 value into the closure.
+    program!(b, search, ancillary, move |x| ((x == x0) as u64, 0.0))
+}
+
+#[cfg(feature = "macros")]
+fn apply_grover_iteration<P: Precision>(x: u64) -> Result<(), CircuitError> {
+    let mut b = LocalBuilder::<f64>::default();
+
+    let n = NonZeroUsize::new(b.n() - 1).unwrap();
+
+    let r = b.register(n);
+    let anc = b.qubit();
+
+    let (r, anc) = apply_uw(&mut b, r, anc, x).unwrap();
+    let (r, _) = apply_us(&mut b, r, anc).unwrap();
+
+    let (_, measured) = b.calculate_state_with_init([(&r, 0b000), (&anc, 0b001)]);
+
+    Ok(())
+}
+
+fn main() {}