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use crate::directed_bijective_connection_graph::lemma2::Lemma2;
use crate::node_path::NodePath;
use crate::{DirectedBijectiveConnectionGraphFunctions, Node};
pub trait NodeToSet {
#[allow(non_snake_case)]
fn N2S(&self, s: Node, d: &[Node]) -> Vec<NodePath>;
fn node_to_set(&self, s: Node, d: &[Node]) -> Vec<NodePath>;
}
impl<F> NodeToSet for F
where
F: DirectedBijectiveConnectionGraphFunctions + Lemma2,
{
#[allow(non_snake_case)]
#[inline(always)]
fn N2S(&self, s: Node, d: &[Node]) -> Vec<NodePath> {
self.node_to_set(s, d)
}
fn node_to_set(&self, s: Node, d: &[Node]) -> Vec<NodePath> {
assert!(d.len() <= self.dimension() as usize);
assert_ne!(d.len(), 0);
if d.len() == 1 {
if d[0] == s {
let mut tmp = NodePath::new(self);
tmp.push_back(s);
return vec![tmp];
} else {
let mut tmp = NodePath::new(self);
tmp.push_back(s);
tmp.push_back(s ^ 1);
return vec![tmp];
}
}
let mut paths;
let dim = d.len() as u64;
let mask = 1 << (dim - 1);
let all_on_same_side_as_src = d
.iter()
.map(|node| *node & mask)
.all(|node_masked| node_masked == s & mask);
if all_on_same_side_as_src {
paths = self.node_to_set(s, &d[..dim as usize - 1]);
paths.push(NodePath::new(self));
debug_assert_eq!(paths.len(), dim as usize);
let mut working_index = dim as usize - 1;
for (index, path) in paths.iter().enumerate() {
if let Some(pos) = path
.inner_path()
.iter()
.position(|&node| node == d[working_index])
{
paths[index].inner_path_mut().truncate(pos);
paths.swap(index, dim as usize - 1);
working_index = index;
break;
}
}
let phi_s = self.phi(dim, s);
let psi_d = self.psi(dim, d[working_index]);
let last_path = &mut paths[working_index];
last_path.push_back(s);
self.R_helper(dim, phi_s, psi_d, last_path);
last_path.push_back(d[working_index]);
} else {
let mut same_ds = d
.iter()
.filter(|&node| node & mask == s & mask)
.copied()
.collect::<Vec<u64>>();
let mut new_d = Vec::with_capacity(dim as usize);
let mut tmp_paths = Vec::with_capacity(self.dimension() as usize);
for &n in d {
if n & mask == s & mask {
new_d.push(n);
tmp_paths.push(NodePath::new(self));
} else {
let dd = self.psi(dim, n);
if !same_ds.contains(&&dd) {
same_ds.push(dd);
new_d.push(dd);
tmp_paths.push({
let mut path = NodePath::new(self);
path.push_back(n);
path
});
} else {
for i in (1..dim).rev() {
let dd = self.psi(i, n);
let ddd = self.psi(dim, dd);
if !same_ds.contains(&&ddd) {
new_d.push(ddd);
tmp_paths.push({
let mut path = NodePath::new(self);
path.push_back(dd);
path.push_back(n);
path
});
break;
}
}
}
}
}
debug_assert_eq!(new_d.len(), dim as usize);
debug_assert_eq!(tmp_paths.len(), dim as usize);
let mut working_index = d.iter().position(|&node| node & mask != s & mask).unwrap();
let dn = d[working_index];
let mut path = NodePath::new(self);
let phi_s = self.phi(dim, s);
path.push_back(s);
path.push_back(phi_s);
self.R_helper(dim, phi_s, dn, &mut path);
'exit: for (index, node) in path.inner_path().iter().enumerate() {
for (path_index, other_path) in tmp_paths.iter().enumerate() {
if let Some(pos) = other_path
.inner_path()
.iter()
.position(|other| node == other)
{
path.inner_path_mut().truncate(index);
path.inner_path_mut()
.extend(other_path.inner_path().iter().skip(pos));
working_index = path_index;
break 'exit;
}
}
}
tmp_paths[working_index] = NodePath::new(self);
new_d.swap(working_index, dim as usize - 1);
let mut partial_paths = self.node_to_set(s, &new_d[..dim as usize - 1]);
partial_paths.push(path);
partial_paths.swap(working_index, dim as usize - 1);
partial_paths
.iter_mut()
.zip(tmp_paths.iter())
.for_each(|(partial_path, path)| {
partial_path
.inner_path_mut()
.extend(path.inner_path().iter())
});
paths = partial_paths;
}
debug_assert_eq!(paths.len(), dim as usize);
paths
}
}
#[cfg(test)]
mod test {
use crate::graphs::HyperCube;
use crate::NodeToSet;
#[test]
fn node_to_set() {
let graph = HyperCube::new(4);
let s = 0b0000;
let d = [0b0001, 0b0011, 0b0111, 0b1111];
let paths = graph.node_to_set(s, &d);
assert_eq!(paths.len(), 4);
paths.iter().zip(d.iter()).for_each(|(path, dest)| {
assert!(path.is_valid());
assert_eq!(path.inner_path().first().unwrap(), &0b0000);
assert_eq!(path.inner_path().last().unwrap(), dest);
});
}
}