Refactor goal API

CHANGELOG.md

@@ -39,6 +39,7 @@ This release focuses on refactorings to simplify code usage and overall maintain
 * refactor route intervals and multi trip enablers
 * refactor feature objective trait
 * refactor dimensions/extras approach to avoid using strings as keys
+* how goal of optimization is defined
 
 
 ## [v1.23.0]- 2023-12-22

vrp-core/examples/custom_constraint.rs

@@ -113,8 +113,7 @@ fn define_goal(transport: Arc<dyn TransportCost + Send + Sync>) -> GenericResult
         .build()?;
 
     // configure goal of optimization
-    GoalContextBuilder::with_features(vec![minimize_unassigned, transport_feature, capacity_feature, hardware_feature])?
-        .set_goal(&["min-unassigned", "min-distance"], &["min-distance"])?
+    GoalContextBuilder::with_features(&[minimize_unassigned, transport_feature, capacity_feature, hardware_feature])?
         .build()
 }
 

vrp-core/examples/custom_objective.rs

@@ -130,13 +130,7 @@ fn define_goal(transport: Arc<dyn TransportCost + Send + Sync>) -> GenericResult
         .build()?;
 
     // configure goal of optimization
-    GoalContextBuilder::with_features(vec![priority_feature, minimize_unassigned, transport_feature, capacity_feature])?
-        .set_goal(
-            // on global level, prefer more maximized jobs over anything else
-            &["maximize-priority", "min-unassigned", "min-distance"],
-            // on local level, prefer it over min-distance as distance is less important
-            &["maximize-priority", "min-distance"],
-        )?
+    GoalContextBuilder::with_features(&[priority_feature, minimize_unassigned, transport_feature, capacity_feature])?
         .build()
 }
 

vrp-core/examples/cvrp.rs

@@ -69,15 +69,10 @@ fn define_goal(transport: Arc<dyn TransportCost + Send + Sync>) -> GenericResult
         .set_time_constrained(false)
         .build_minimize_distance()?;
 
-    // configure goal of optimization
-    GoalContextBuilder::with_features(vec![minimize_unassigned, transport_feature, capacity_feature])?
-        // the goal is split into global and local parts:
-        // - on global level we prefer solutions where:
-        //   1. minimum of unassigned jobs
-        //   2. minimum distance traveled
-        // - on local level, as all jobs have the same weight, we prefer jobs that introduce a minimal distance change
-        .set_goal(&["min-unassigned", "min-distance"], &["min-distance"])?
-        .build()
+    // configure goal of optimization: features with objectives are read from ordered feature list. Here we have:
+    //   1. minimum of unassigned jobs as the main objective
+    //   2. minimum distance traveled
+    GoalContextBuilder::with_features(&[minimize_unassigned, transport_feature, capacity_feature])?.build()
 }
 
 fn main() -> GenericResult<()> {

vrp-core/examples/pdptw.rs

@@ -83,14 +83,7 @@ fn define_goal(transport: Arc<dyn TransportCost + Send + Sync>) -> GenericResult
         .build_minimize_distance()?;
 
     // configure goal of optimization
-    GoalContextBuilder::with_features(vec![minimize_unassigned, transport_feature, capacity_feature])?
-        // the goal is split into global and local parts:
-        // - on global level we prefer solutions where:
-        //   1. minimum of unassigned jobs
-        //   2. minimum distance traveled
-        // - on local level, as all jobs have the same weight, we prefer jobs that introduce a minimal distance change
-        .set_goal(&["min-unassigned", "min-distance"], &["min-distance"])?
-        .build()
+    GoalContextBuilder::with_features(&[minimize_unassigned, transport_feature, capacity_feature])?.build()
 }
 
 fn main() -> GenericResult<()> {

vrp-core/src/construction/enablers/feature_combinator.rs

@@ -115,8 +115,19 @@ impl FeatureState for CombinedFeatureState {
         accept_route_state_with_states(&self.states, route_ctx)
     }
 
-    fn accept_solution_state(&self, solution_ctx: &mut SolutionContext) {
-        accept_solution_state_with_states(&self.states, solution_ctx)
+    fn accept_solution_state(&self, ctx: &mut SolutionContext) {
+        // NOTE should not use a version with fallback to avoid hiding changes for other states
+        self.states.iter().try_for_each(|state| {
+            let previous_state = (ctx.required.len(), ctx.ignored.len(), ctx.unassigned.len());
+
+            state.accept_solution_state(ctx);
+
+            if has_changes(ctx, previous_state) {
+                ControlFlow::Break(())
+            } else {
+                ControlFlow::Continue(())
+            }
+        });
     }
 }
 
@@ -183,11 +194,6 @@ pub(crate) fn accept_route_state_with_states(states: &[Arc<dyn FeatureState>], r
 }
 
 pub(crate) fn accept_solution_state_with_states(states: &[Arc<dyn FeatureState>], solution_ctx: &mut SolutionContext) {
-    let has_changes = |ctx: &SolutionContext, previous_state: (usize, usize, usize)| {
-        let (required, ignored, unassigned) = previous_state;
-        required != ctx.required.len() || ignored != ctx.ignored.len() || unassigned != ctx.unassigned.len()
-    };
-
     let _ = (0..).try_fold((usize::MAX, usize::MAX, usize::MAX), |(required, ignored, unassigned), counter| {
         // NOTE if any job promotion occurs, then we might need to recalculate states.
         // As it is hard to maintain dependencies between different modules, we reset process to
@@ -244,3 +250,11 @@ pub(crate) fn evaluate_with_constraints(
         })
         .unwrap_value()
 }
+
+fn has_changes(solution_ctx: &SolutionContext, previous_state: (usize, usize, usize)) -> bool {
+    let (required, ignored, unassigned) = previous_state;
+
+    required != solution_ctx.required.len()
+        || ignored != solution_ctx.ignored.len()
+        || unassigned != solution_ctx.unassigned.len()
+}

vrp-core/src/models/examples.rs

@@ -69,9 +69,7 @@ fn create_example_goal_ctx(
         CapacityFeatureBuilder::<SingleDimLoad>::new("capacity").build()?,
     ];
 
-    GoalContextBuilder::with_features(features)?
-        .set_goal(&["min_jobs", "min_tours", "min_distance"], &["min_tours", "min_distance"])?
-        .build()
+    GoalContextBuilder::with_features(&features)?.build()
 }
 
 pub fn build_example_problem() -> GenericResult<Arc<Problem>> {