From 012b079e46376fbd632b84a06fdedaf1117e34ea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ji=C5=99=C3=AD=20Sejkora?= <sejsel@sejsel.cz>
Date: Sun, 21 Feb 2021 00:00:42 +0100
Subject: [PATCH] Fix combine not retrying the same axis multiple times

---
 src/combine.rs | 54 ++++++++++++++++++++++++++------------------------
 1 file changed, 28 insertions(+), 26 deletions(-)

diff --git a/src/combine.rs b/src/combine.rs
index 36d5006..7b5c6a8 100644
--- a/src/combine.rs
+++ b/src/combine.rs
@@ -50,45 +50,47 @@ fn choose_layouts<TDB: LayoutDB>(db: &TDB, city: &City, top_layout_count: usize)
 }
 
 pub fn iterate_combines<TDB: LayoutDB>(mut db: &mut TDB, top_layout_count: usize, city: &City, mut cache: &mut CompatibilityCache, print_progress: bool) {
-    #[derive(Eq, PartialEq)]
-    enum LastStep {
-        None,
-        Vertical,
-        Horizontal,
-    }
+    let mut no_improvements_in_a_row = 0;
     if print_progress { eprintln!("Building a transposed city..."); }
     let transposed_city = transpose_city(&city);
     if print_progress { eprintln!("Finished building a transposed city"); }
 
-    if print_progress { eprintln!("Building right distances..."); }
-    let right_distances = city::build_distances_right(&city);
-    if print_progress { eprintln!("Building right distances (transposed)..."); }
-    let right_distances_transposed = city::build_distances_right(&city);
-    if print_progress { eprintln!("Finished building right distances"); }
-
-    let mut last_improve_step = LastStep::None;
     loop {
-        if last_improve_step == LastStep::Vertical { break; }
+        if no_improvements_in_a_row == 2 { break; }
         if print_progress { eprintln!("Starting to combine {} top houses DB; vertical cuts", top_layout_count); }
 
-        let chosen_layouts = choose_layouts(db, &city, top_layout_count);
-        if create_new_best_combination(&city, &chosen_layouts, &chosen_layouts, db, &mut cache, &right_distances, false, print_progress) {
-            last_improve_step = LastStep::Vertical;
+        {
+            let chosen_layouts = choose_layouts(db, &city, top_layout_count);
+            if print_progress { eprintln!("Building right distances..."); }
+            let right_distances = city::build_distances_right(&city);
+            if print_progress { eprintln!("Finished building right distances"); }
+            if create_new_best_combination(&city, &chosen_layouts, &chosen_layouts, db, &mut cache, &right_distances, false, print_progress) {
+                no_improvements_in_a_row = 0;
+            } else {
+                no_improvements_in_a_row += 1;
+            }
+            if print_progress { eprintln!("Finished vertical cuts, improvement: {}", no_improvements_in_a_row == 0); }
         }
-        if print_progress { eprintln!("Finished vertical cuts, improvement: {}", last_improve_step == LastStep::Vertical); }
 
-        if last_improve_step == LastStep::Horizontal { break; }
+        if no_improvements_in_a_row == 2 { break; }
 
-        let chosen_layouts = choose_layouts(db, &city, top_layout_count);
-        let transposed_chosen_layouts: Vec<_> = chosen_layouts.iter().map(|x| transpose_saved_layout(x)).collect();
+        {
+            let chosen_layouts = choose_layouts(db, &city, top_layout_count);
+            let transposed_chosen_layouts: Vec<_> = chosen_layouts.iter().map(|x| transpose_saved_layout(x)).collect();
+            if print_progress { eprintln!("Building right distances (transposed)..."); }
+            let right_distances_transposed = city::build_distances_right(&transposed_city);
+            if print_progress { eprintln!("Finished building right distances"); }
 
-        if print_progress { eprintln!("Starting to combine {} top houses DB; horizontal cuts", top_layout_count); }
-        if create_new_best_combination(&transposed_city, &transposed_chosen_layouts, &transposed_chosen_layouts, db, &mut cache, &right_distances_transposed, true, print_progress) {
-            last_improve_step = LastStep::Horizontal;
+            if print_progress { eprintln!("Starting to combine {} top houses DB; horizontal cuts", top_layout_count); }
+            if create_new_best_combination(&transposed_city, &transposed_chosen_layouts, &transposed_chosen_layouts, db, &mut cache, &right_distances_transposed, true, print_progress) {
+                no_improvements_in_a_row = 0;
+            } else {
+                no_improvements_in_a_row += 1;
+            }
+            if print_progress { eprintln!("Finished horizontal cuts, improvement: {}", no_improvements_in_a_row == 0); }
         }
-        if print_progress { eprintln!("Finished horizontal cuts, improvement: {}", last_improve_step == LastStep::Horizontal); }
 
-        if last_improve_step == LastStep::None { break; }
+        if no_improvements_in_a_row == 2 { break; }
     }
 }