pumpkin_core/propagators/nogoods/
learning_options.rs

1/// Options related to nogood management, i.e., how and when to remove learned nogoods from the
2/// database.
3#[derive(Debug, Copy, Clone)]
4pub struct LearningOptions {
5    /// Determines when to rescale the activites of the learned nogoods in the database.
6    pub max_activity: f32,
7    /// Determines the factor by which the activities are divided when a conflict is found.
8    pub activity_decay_factor: f32,
9    /// The solver partitions the nogoods into three tiers.
10    ///
11    /// This limit specifies how many nogoods can be stored in the "high" LBD tier.
12    pub max_num_high_lbd_nogoods: usize,
13    /// The solver partitions the nogoods into three tiers.
14    ///
15    /// This limit specifies how many nogoods can be stored in the "mid" LBD tier.
16    pub max_num_mid_lbd_nogoods: usize,
17    /// The solver partitions the nogoods into three tiers.
18    ///
19    /// This limit specifies how many nogoods can be stored in the "low" LBD tier.
20    pub max_num_low_lbd_nogoods: usize,
21    /// Used to determine which tier a nogood belongs in.
22    ///
23    /// If the LBD of a nogood is higher than or equal to this threshold then it is considered to
24    /// be a "high" LBD nogood.
25    ///
26    /// If the LBD of a nogood is between [`LearningOptions::lbd_threshold_high`] and
27    /// [`LearningOptions::lbd_threshold_low`] then it is considered a "mid" LBD nogood.
28    pub lbd_threshold_high: u32,
29    /// Used to determine which tier a nogood belongs in.
30    ///
31    /// If the LBD of a nogood is lower than or equal to this value then it is considered to be a
32    /// "low" LBD nogood.
33    ///
34    /// If the LBD of a nogood is between [`LearningOptions::lbd_threshold_high`] and
35    /// [`LearningOptions::lbd_threshold_low`] then it is considered a "mid" LBD nogood.
36    pub lbd_threshold_low: u32,
37    /// Specifies by how much the activity is increased when a nogood is bumped.
38    pub activity_bump_increment: f32,
39}
40impl Default for LearningOptions {
41    fn default() -> Self {
42        Self {
43            max_activity: 1e20,
44            activity_decay_factor: 0.99,
45            max_num_high_lbd_nogoods: 20000,
46            max_num_mid_lbd_nogoods: 7000,
47            max_num_low_lbd_nogoods: 100000,
48            lbd_threshold_high: 7,
49            lbd_threshold_low: 3,
50            activity_bump_increment: 1.0,
51        }
52    }
53}
pumpkin_core/propagators/nogoods/learning_options.rs

pumpkin_core/propagators/nogoods/
learning_options.rs
