Skip to content

Improve readability #206

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
mmghannam merged 2 commits into from
Jan 30, 2025
Merged

Improve readability #206

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
22ed139
Improve readability
mmghannam Jan 30, 2025
a3dac45
Improve loop
mmghannam Jan 30, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
39 changes: 22 additions & 17 deletions examples/knapsack.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,16 +1,23 @@
use russcip::minimal_model;
use russcip::prelude::*;

/// 0-1 Knapsack problem
#[derive(Debug)]
struct Knapsack {
/// Sizes of the items
sizes: Vec<usize>,
/// Values of the items
values: Vec<usize>,
/// Capacity of the knapsack
capacity: usize,
}

/// Solution to the knapsack problem
#[derive(Debug)]
struct KnapsackSolution {
/// Indices of the items in the solution
items: Vec<usize>,
/// Total value of the solution
value: f64,
}

Expand All @@ -32,29 +39,27 @@ impl Knapsack {
fn solve(&self) -> KnapsackSolution {
let mut model = minimal_model().maximize();

let vars: Vec<_> = self
.values
.iter()
.map(|&value| model.add(var().binary().obj(value as f64)))
.collect();
let mut vars = Vec::with_capacity(self.sizes.len());
for i in 0..self.sizes.len() {
vars.push(model.add(var().binary().obj(self.values[i] as f64)));
}

let var_sizes = vars
.iter()
.zip(self.sizes.iter())
.map(|(var, &size)| (var, size as f64));
model.add(cons().le(self.capacity as f64).expr(var_sizes));
let mut capacity_cons = cons().le(self.capacity as f64);
for (i, var) in vars.iter().enumerate() {
capacity_cons = capacity_cons.coef(var, self.sizes[i] as f64);
}
model.add(capacity_cons);

let solved_model = model.solve();

let sol = solved_model.best_sol().unwrap();
let items: Vec<_> = vars
.iter()
.enumerate()
.filter(|(_, v)| sol.val(v) > 1e-6)
.map(|(i, _)| i)
.collect();
let mut items = vec![];
for (i, var) in vars.iter().enumerate() {
if sol.val(var) > 0.5 {
items.push(i);
}
}
let value = sol.obj_val();

KnapsackSolution { items, value }
}
}
Expand Down
Loading