breaking things up, refactors Problem with vectors...

This commit is contained in:
2019-02-14 21:50:19 +01:00
parent 04e8c554cc
commit 4b21fd873b

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@@ -7,11 +7,11 @@ use std::clone::Clone;
use std::collections::HashMap; use std::collections::HashMap;
/// An assignments map of variables /// An assignments map of variables
pub type Variables<'a, V, K> = HashMap<K, Option<&'a V>>; pub type Variables<'a, V> = Vec<Option<&'a V>>;
enum Assignment<'a, V, K> { enum Assignment<'a, V> {
Update(K, &'a V), Update(usize, &'a V),
Clear(K) Clear(usize)
} }
/// Collection of references to values owned by a domain. /// Collection of references to values owned by a domain.
@@ -99,7 +99,7 @@ impl<V: fmt::Debug> fmt::Debug for Domain<V> {
} }
pub type Constraint<'a,V, K> = fn(&Variables<'a,V, K>) -> bool; pub type Constraint<'a,V> = fn(&Variables<'a,V>) -> bool;
/// Could be more efficient to just use fixed array of options as variables, /// Could be more efficient to just use fixed array of options as variables,
@@ -108,12 +108,13 @@ pub type Constraint<'a,V, K> = fn(&Variables<'a,V, K>) -> bool;
/// It makes sense with an array where indexing is O(1) /// It makes sense with an array where indexing is O(1)
pub struct Problem<'a, V, K> { pub struct Problem<'a, V, K> {
keys: Vec<K>,
/// The initial assignements map /// The initial assignements map
variables: Variables<'a, V, K>, variables: Variables<'a, V>,
/// Each variable has its associated domain /// Each variable has its associated domain
domains: HashMap<K, DomainValues<'a,V>>, domains: Vec<DomainValues<'a,V>>,
/// Set of constraints to validate /// Set of constraints to validate
constraints: Vec<Constraint<'a,V,K>>, constraints: Vec<Constraint<'a,V>>,
} }
impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> { impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
@@ -130,7 +131,7 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
/// Returns all possible Updates for next assignements, prepended with /// Returns all possible Updates for next assignements, prepended with
/// a Clear to ensure the variable is unset before when leaving the branch. /// a Clear to ensure the variable is unset before when leaving the branch.
fn _push_updates(&self) -> Option<Vec<Assignment<'a,V, K>>> { fn _push_updates(&self) -> Option<Vec<Assignment<'a,V>>> {
// TODO: should be able to inject a choosing strategy // TODO: should be able to inject a choosing strategy
if let Some(key) = self._next_assign() { if let Some(key) = self._next_assign() {
let domain_values = self.domains let domain_values = self.domains
@@ -142,10 +143,7 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
// TODO: should be able to filter domain values (inference, pertinence) // TODO: should be able to filter domain values (inference, pertinence)
domain_values.iter().for_each(|value| { domain_values.iter().for_each(|value| {
updates.push( updates.push(
Assignment::Update( Assignment::Update(key, *value)
key.clone(),
*value
)
); );
}); });
Some(updates) Some(updates)
@@ -154,11 +152,11 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
} }
} }
fn _next_assign(&self) -> Option<&K> { fn _next_assign(&self) -> Option<usize> {
self.variables self.variables.iter()
.iter() .enumerate()
.find_map(|(key, val)| { .find_map(|(idx, val)| {
if val.is_none() { Some(key) } if val.is_none() { Some(idx) }
else { None } else { None }
}) })
} }
@@ -172,12 +170,12 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
} }
/// Returns all complete solutions, after visiting all possible outcomes using a stack (DFS). /// Returns all complete solutions, after visiting all possible outcomes using a stack (DFS).
pub fn solve_all(&mut self) -> Vec<Variables<'a,V,K>> pub fn solve_all(&mut self) -> Vec<Variables<'a,V>>
where V: Clone + fmt::Debug, where V: Clone + fmt::Debug,
K: Clone + fmt::Debug, K: Clone + fmt::Debug,
{ {
let mut solutions: Vec<Variables<V, K>> = vec![]; let mut solutions: Vec<Variables<V>> = vec![];
let mut stack: Vec<Assignment<'a, V, K>> = vec![]; let mut stack: Vec<Assignment<'a, V>> = vec![];
if let Some(mut init_updates) = self._push_updates() { if let Some(mut init_updates) = self._push_updates() {
stack.append(&mut init_updates); stack.append(&mut init_updates);
} else { } else {
@@ -189,9 +187,9 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
let node = stack.pop(); let node = stack.pop();
if node.is_none() { break; }; if node.is_none() { break; };
match node.unwrap() { match node.unwrap() {
Assignment::Update(key, val) => { Assignment::Update(idx, val) => {
// Assign the variable and open new branches, if any. // Assign the variable and open new branches, if any.
*self.variables.get_mut(&key).unwrap() = Some(val); self.variables[idx] = Some(val);
// TODO: handle case of empty domain.values // TODO: handle case of empty domain.values
if let Some(mut nodes) = self._push_updates() { if let Some(mut nodes) = self._push_updates() {
stack.append(&mut nodes); stack.append(&mut nodes);
@@ -202,20 +200,20 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
}; };
}; };
}, },
Assignment::Clear(key) => { Assignment::Clear(idx) => {
// We are closing this branch, unset the variable // We are closing this branch, unset the variable
*self.variables.get_mut(&key).unwrap() = None; self.variables[idx] = None;
}, },
}; };
}; };
solutions solutions
} }
pub fn solve_one(&mut self) -> Option<Variables<'a,V,K>> pub fn solve_one(&mut self) -> Option<Variables<'a,V>>
where V: Clone + fmt::Debug, where V: Clone + fmt::Debug,
K: Clone + fmt::Debug, K: Clone + fmt::Debug,
{ {
let mut stack: Vec<Assignment<'a, V, K>> = vec![]; let mut stack: Vec<Assignment<'a, V>> = vec![];
if let Some(mut init_updates) = self._push_updates() { if let Some(mut init_updates) = self._push_updates() {
stack.append(&mut init_updates); stack.append(&mut init_updates);
} else { } else {
@@ -228,9 +226,9 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
return None; return None;
}; };
match node.unwrap() { match node.unwrap() {
Assignment::Update(key, val) => { Assignment::Update(idx, val) => {
// Assign the variable and open new branches, if any. // Assign the variable and open new branches, if any.
*self.variables.get_mut(&key).unwrap() = Some(val); self.variables[idx] = Some(val);
// TODO: handle case of empty domain.values // TODO: handle case of empty domain.values
if let Some(mut nodes) = self._push_updates() { if let Some(mut nodes) = self._push_updates() {
stack.append(&mut nodes); stack.append(&mut nodes);
@@ -241,9 +239,9 @@ impl<'a, V, K: Eq + Hash + Clone> Problem<'a, V, K> {
}; };
}; };
}, },
Assignment::Clear(key) => { Assignment::Clear(idx) => {
// We are closing this branch, unset the variable // We are closing this branch, unset the variable
*self.variables.get_mut(&key).unwrap() = None; self.variables[idx] = None;
}, },
}; };
} }
@@ -256,20 +254,22 @@ impl<'a, V, K: Eq + Hash + Clone> ProblemBuilder<'a, V, K> {
fn new() -> ProblemBuilder<'a, V, K> { fn new() -> ProblemBuilder<'a, V, K> {
ProblemBuilder( ProblemBuilder(
Problem{ Problem{
keys: Vec::new(),
variables: Variables::new(), variables: Variables::new(),
domains: HashMap::new(), domains: Vec::new(),
constraints: Vec::new(), constraints: Vec::new(),
}) })
} }
pub fn add_variable(mut self, name: K, domain: Vec<&'a V>, value: Option<&'a V>) -> Self pub fn add_variable(mut self, name: K, domain: Vec<&'a V>, value: Option<&'a V>) -> Self
{ {
self.0.variables.insert(name.clone(), value); self.0.keys.push(name);
self.0.domains.insert(name, domain); self.0.variables.push(value);
self.0.domains.push(domain);
self self
} }
pub fn add_constraint(mut self, cons: Constraint<'a,V, K>) -> Self { pub fn add_constraint(mut self, cons: Constraint<'a,V>) -> Self {
self.0.constraints.push(cons); self.0.constraints.push(cons);
self self
} }
@@ -289,15 +289,15 @@ mod tests {
let mut problem: Problem<_, _> = Problem::build() let mut problem: Problem<_, _> = Problem::build()
.add_variable(String::from("Left"), domain.all(), None) .add_variable(String::from("Left"), domain.all(), None)
.add_variable(String::from("Right"), domain.all(), None) .add_variable(String::from("Right"), domain.all(), None)
.add_constraint(|assign: &Variables<i32, _>| { .add_constraint(|assign: &Variables<i32>| {
assign.get("Left").unwrap() == assign.get("Right").unwrap() assign[0] == assign[1]
}) })
.finish(); .finish();
let solutions: Vec<Variables<i32, _>> = vec![ let solutions: Vec<Variables<i32>> = vec![
[("Left".to_string(), Some(&3)), ("Right".to_string(), Some(&3)),].iter().cloned().collect(), [Some(&3), Some(&3)].iter().cloned().collect(),
[("Left".to_string(), Some(&2)), ("Right".to_string(), Some(&2)),].iter().cloned().collect(), [Some(&2), Some(&2)].iter().cloned().collect(),
[("Left".to_string(), Some(&1)), ("Right".to_string(), Some(&1)),].iter().cloned().collect(), [Some(&1), Some(&1)].iter().cloned().collect(),
]; ];
assert_eq!(problem.solve_all(), solutions); assert_eq!(problem.solve_all(), solutions);
@@ -310,13 +310,13 @@ mod tests {
let mut problem: Problem<_, _> = Problem::build() let mut problem: Problem<_, _> = Problem::build()
.add_variable("Left".to_string(), domain.all(), None) .add_variable("Left".to_string(), domain.all(), None)
.add_variable("Right".to_string(), domain.all(), Some(&2)) .add_variable("Right".to_string(), domain.all(), Some(&2))
.add_constraint( |assign: &Variables<i32, _>| { .add_constraint( |assign: &Variables<i32>| {
assign.get("Left").unwrap() == assign.get("Right").unwrap() assign[0] == assign[1]
}) })
.finish(); .finish();
let solutions: Vec<Variables<i32, _>> = vec![ let solutions: Vec<Variables<i32>> = vec![
[("Left".to_string(), Some(&2)), ("Right".to_string(), Some(&2)),].iter().cloned().collect(), [Some(&2), Some(&2)].iter().cloned().collect(),
]; ];
assert_eq!(problem.solve_all(), solutions); assert_eq!(problem.solve_all(), solutions);