From fa9a5aff839b19a79677e6fdc8f605456c389f08 Mon Sep 17 00:00:00 2001
From: Rutherther <rutherther@ditigal.xyz>
Date: Tue, 28 Oct 2025 16:27:49 +0100
Subject: [PATCH] feat: add plotting of TSP

---
 codes/tsp_hw01/Cargo.toml |  1 +
 codes/tsp_hw01/src/tsp.rs | 68 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+)

diff --git a/codes/tsp_hw01/Cargo.toml b/codes/tsp_hw01/Cargo.toml
index ed229b7aeccaf2240281432be58aaee2941b8622..ba5531cc3db55a2c6e330056c16db52fe8f5b3ab 100644
--- a/codes/tsp_hw01/Cargo.toml
+++ b/codes/tsp_hw01/Cargo.toml
@@ -7,4 +7,5 @@ edition = "2024"
 eoa_lib = { path = "../eoa_lib" }
 itertools = "0.14.0"
 nalgebra = "0.33.2"
+plotters = "0.3"
 rand = "0.9.2"
diff --git a/codes/tsp_hw01/src/tsp.rs b/codes/tsp_hw01/src/tsp.rs
index b59a164db8bbc9a8f6f636e7d97f30365711f52a..4bbc06afa34ae1513099a6eeece727848c94bcd5 100644
--- a/codes/tsp_hw01/src/tsp.rs
+++ b/codes/tsp_hw01/src/tsp.rs
@@ -3,6 +3,7 @@ use std::{convert::Infallible, marker::PhantomData};
 use eoa_lib::{fitness::FitnessFunction, initializer::Initializer, perturbation::PerturbationOperator};
 use itertools::Itertools;
 use nalgebra::{allocator::Allocator, distance, Const, DefaultAllocator, Dim, Dyn, OMatrix, OVector, Point, U1};
+use plotters::prelude::*;
 use rand::{seq::SliceRandom, Rng, RngCore};
 
 #[derive(PartialEq, Clone, Debug)]
@@ -117,6 +118,73 @@ where
             .map(|(&node1, &node2): (&usize, &usize)| self.distances[(node1, node2)])
             .sum()
     }
+
+    fn plot_internal(&self, solution: Option<&NodePermutation<D>>, filename: &str) -> Result<(), Box<dyn std::error::Error>> {
+        let root = BitMapBackend::new(filename, (800, 600)).into_drawing_area();
+        root.fill(&WHITE)?;
+
+        let x_coords: Vec<f64> = self.cities.iter().map(|city| city.point.x).collect();
+        let y_coords: Vec<f64> = self.cities.iter().map(|city| city.point.y).collect();
+
+        let x_min = x_coords.iter().fold(f64::INFINITY, |a, &b| a.min(b));
+        let x_max = x_coords.iter().fold(f64::NEG_INFINITY, |a, &b| a.max(b));
+        let y_min = y_coords.iter().fold(f64::INFINITY, |a, &b| a.min(b));
+        let y_max = y_coords.iter().fold(f64::NEG_INFINITY, |a, &b| a.max(b));
+
+        let x_padding = (x_max - x_min) * 0.1;
+        let y_padding = (y_max - y_min) * 0.1;
+
+        let x_range = (x_min - x_padding)..(x_max + x_padding);
+        let y_range = (y_min - y_padding)..(y_max + y_padding);
+
+        let title = if let Some(sol) = solution {
+            format!("TSP Solution (Cost: {:.2})", self.solution_cost(sol))
+        } else {
+            "TSP Instance".to_string()
+        };
+
+        let mut chart = ChartBuilder::on(&root)
+            .caption(&title, ("sans-serif", 40))
+            .margin(10)
+            .x_label_area_size(40)
+            .y_label_area_size(40)
+            .build_cartesian_2d(x_range, y_range)?;
+
+        chart.configure_mesh().draw()?;
+
+        if let Some(sol) = solution {
+            chart.draw_series(
+                sol.permutation.iter().circular_tuple_windows().map(|(&city1_idx, &city2_idx)| {
+                    let city1 = &self.cities[city1_idx];
+                    let city2 = &self.cities[city2_idx];
+                    PathElement::new(vec![(city1.point.x, city1.point.y), (city2.point.x, city2.point.y)], BLUE)
+                })
+            )?;
+        }
+
+        chart.draw_series(
+            self.cities.iter().map(|city| {
+                Circle::new((city.point.x, city.point.y), 5, RED.filled())
+            })
+        )?;
+
+        chart.draw_series(
+            self.cities.iter().enumerate().map(|(i, city)| {
+                Text::new(format!("{}", i), (city.point.x + 0.1, city.point.y + 0.1), ("sans-serif", 15))
+            })
+        )?;
+
+        root.present()?;
+        Ok(())
+    }
+
+    pub fn plot(&self, filename: &str) -> Result<(), Box<dyn std::error::Error>> {
+        self.plot_internal(None, filename)
+    }
+
+    pub fn draw_solution(&self, solution: &NodePermutation<D>, filename: &str) -> Result<(), Box<dyn std::error::Error>> {
+        self.plot_internal(Some(solution), filename)
+    }
 }
 
 impl<D> FitnessFunction for TSPInstance<D>