solverforge_core/score/
traits.rs

1//! Core Score trait definition
2
3use std::cmp::Ordering;
4use std::fmt::Debug;
5use std::ops::{Add, Neg, Sub};
6
7/// Core trait for all score types in SolverForge.
8///
9/// Scores represent the quality of a planning solution. They are used to:
10/// - Compare solutions (better/worse/equal)
11/// - Guide the optimization process
12/// - Determine feasibility
13///
14/// All score implementations must be:
15/// - Immutable (operations return new instances)
16/// - Thread-safe (Send + Sync)
17/// - Comparable (total ordering)
18///
19/// # Score Levels
20///
21/// Scores can have multiple levels (e.g., hard/soft constraints):
22/// - Hard constraints: Must be satisfied for a solution to be feasible
23/// - Soft constraints: Optimization objectives to maximize/minimize
24///
25/// When comparing scores, higher-priority levels are compared first.
26pub trait Score:
27    Clone
28    + Debug
29    + Default
30    + Send
31    + Sync
32    + PartialEq
33    + Eq
34    + PartialOrd
35    + Ord
36    + Add<Output = Self>
37    + Sub<Output = Self>
38    + Neg<Output = Self>
39    + 'static
40{
41    /// Returns true if this score represents a feasible solution.
42    ///
43    /// A solution is feasible when all hard constraints are satisfied
44    /// (i.e., the hard score is >= 0).
45    fn is_feasible(&self) -> bool;
46
47    /// Returns the zero score (identity element for addition).
48    fn zero() -> Self;
49
50    /// Returns the number of score levels.
51    ///
52    /// For example:
53    /// - SimpleScore: 1 level
54    /// - HardSoftScore: 2 levels
55    /// - HardMediumSoftScore: 3 levels
56    fn levels_count() -> usize;
57
58    /// Returns the score values as a vector of i64.
59    ///
60    /// The order is from highest priority to lowest priority.
61    /// For HardSoftScore: [hard, soft]
62    fn to_level_numbers(&self) -> Vec<i64>;
63
64    /// Creates a score from level numbers.
65    ///
66    /// # Panics
67    /// Panics if the number of levels doesn't match `levels_count()`.
68    fn from_level_numbers(levels: &[i64]) -> Self;
69
70    /// Multiplies this score by a scalar.
71    fn multiply(&self, multiplicand: f64) -> Self;
72
73    /// Divides this score by a scalar.
74    fn divide(&self, divisor: f64) -> Self;
75
76    /// Returns the absolute value of this score.
77    fn abs(&self) -> Self;
78
79    /// Compares two scores, returning the ordering.
80    ///
81    /// Default implementation uses the Ord trait.
82    fn compare(&self, other: &Self) -> Ordering {
83        self.cmp(other)
84    }
85
86    /// Returns true if this score is better than the other score.
87    ///
88    /// In optimization, "better" typically means higher score.
89    fn is_better_than(&self, other: &Self) -> bool {
90        self > other
91    }
92
93    /// Returns true if this score is worse than the other score.
94    fn is_worse_than(&self, other: &Self) -> bool {
95        self < other
96    }
97
98    /// Returns true if this score is equal to the other score.
99    fn is_equal_to(&self, other: &Self) -> bool {
100        self == other
101    }
102}
103
104/// Marker trait for scores that can be parsed from a string.
105pub trait ParseableScore: Score {
106    /// Parses a score from a string representation.
107    ///
108    /// # Format
109    /// - SimpleScore: "42" or "42init"
110    /// - HardSoftScore: "0hard/-100soft" or "-1hard/0soft"
111    /// - HardMediumSoftScore: "0hard/0medium/-100soft"
112    fn parse(s: &str) -> Result<Self, ScoreParseError>;
113
114    /// Returns the string representation of this score.
115    fn to_string_repr(&self) -> String;
116}
117
118/// Error when parsing a score from string
119#[derive(Debug, Clone, PartialEq, Eq)]
120pub struct ScoreParseError {
121    pub message: String,
122}
123
124impl std::fmt::Display for ScoreParseError {
125    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
126        write!(f, "Score parse error: {}", self.message)
127    }
128}
129
130impl std::error::Error for ScoreParseError {}
solverforge_core/score/traits.rs

solverforge_core/score/
traits.rs
