Done c++ ant colony opt with 2.5opt = 7.5

This commit is contained in:
Claudio Maggioni 2020-11-29 22:17:17 +01:00
parent 9f61b503d1
commit 55fa9b5d64
15 changed files with 670 additions and 1868 deletions

141
.gitignore vendored
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/Complete notebooks/
/Lectures/.ipynb_checkpoints/
/.ipynb_checkpoints/Student_lecture 1-checkpoint.ipynb
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c_prob/*
!c_prob/.gitkeep

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"## Fourth Lecture"
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aco.cc Normal file
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// vim: set ts=2 sw=2 et tw=80:
// compile with
// g++ -lpthread --std=c++11 -o c_prob/aco aco.cc
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <pthread.h>
#include <vector>
#include <set>
#include <iostream>
#include <algorithm>
#include <unistd.h>
using namespace std;
typedef unsigned int uint;
ostream& operator<< (ostream& out, vector<uint> a) {
out << "[";
for (int i = 0; i < a.size() - 1; i++) {
out << a[i] << ",";
}
out << a[a.size() - 1] << "]";
return out;
}
const uint MAX_NODES = 1577;
// alpha >= 0
double alpha;
// beta >= 1
double beta;
double pheromone_evaporation_coeff;
double pheromone_constant;
uint n_iterations;
uint n_ants;
uint n_nodes;
double dist_matrix[MAX_NODES][MAX_NODES];
double pheromone_map[MAX_NODES][MAX_NODES];
double ant_updated_pheromone_map[MAX_NODES][MAX_NODES];
double sh_dist;
vector<uint> sh_route;
bool first_pass;
uint start;
uint select_random(const set<uint> &s) {
auto n = rand() % s.size(); // not _really_ random
auto it = begin(s);
advance(it, n); // 'advance' the iterator n times
return *it;
}
struct ant {
uint other;
uint idx;
pthread_t t_handle;
uint location;
double distance_travelled;
set<uint> possible_locations;
vector<uint> route;
bool tour_complete = false;
void init() {
this->other = 0;
this->distance_travelled = 0.0;
this->route.clear();
this->possible_locations.clear();
for (size_t i = 0; i < n_nodes; i++) {
this->possible_locations.insert(i);
}
this->location = start;
this->update_route(start);
this->tour_complete = false;
};
void update_route(uint new_loc) {
this->route.push_back(new_loc);
this->possible_locations.erase(new_loc);
};
uint pick_path() {
if (first_pass) {
return select_random(this->possible_locations);
} else {
double attractiveness[n_nodes];
double sum_total = 0.0;
vector<uint> idxs;
for (uint loc : this->possible_locations) {
idxs.push_back(loc);
double pheromone_amount = pheromone_map[this->location][loc];
double distance = dist_matrix[this->location][loc];
if (distance == 0) { distance = 0.000000001; };
attractiveness[loc] = pow(pheromone_amount, alpha) *
pow(1 / distance, beta);
//cerr << "ant " << idx << " attr[loc]=" << attractiveness[loc] << endl;
sum_total += attractiveness[loc];
if (isnan(sum_total)) { cerr << "nanalert " << attractiveness[loc] <<
" " << pheromone_amount << " " << distance << endl; }
}
// it is possible to have small values for pheromone amount / distance,
// such that with rounding errors this is equal to zero
if (sum_total == 0.0) {
// increment all zero's, such that they are the smallest non-zero
// values supported by the system
// source: http://stackoverflow.com/a/10426033/5343977
for (uint loc : idxs) {
attractiveness[loc] = nextafter(attractiveness[loc],
std::numeric_limits<double>::infinity());
}
sum_total = nextafter(sum_total, std::numeric_limits<double>::infinity());
}
double toss = (double) rand() / (double) RAND_MAX;
// cerr << "ant " << idx << " sum_total is " << sum_total << " toss is " << toss << endl;
double cumulative = 0.0;
for (uint loc : idxs) {
double weight = (attractiveness[loc] / sum_total);
//cerr << "ant " << idx << " w: " << weight + cumulative << endl;
if (toss <= (weight + cumulative)) {
return loc;
}
cumulative += weight;
}
cerr << "cum " << cumulative << " n " << idxs.size() << " toss " << toss << endl;
sleep(1);
other++;
// cerr << "ant " << idx << " change statement" << endl;
return idxs[idxs.size() - 1];
}
};
void traverse(uint next) {
this->update_route(next);
this->distance_travelled += dist_matrix[this->location][next];
this->location = next;
//cerr << "traversing " << next << " dist: " << this->distance_travelled << endl;
}
void run() {
// cerr << "started ant - # can pick: " << this->possible_locations.size() << endl;
while (!this->possible_locations.empty()) {
uint next = this->pick_path();
this->traverse(next);
}
this->distance_travelled += dist_matrix[this->route[this->route.size() - 1]]
[this->route[0]];
// cerr << "stopped ant" << endl;
this->tour_complete = true;
}
};
void *ant_thread (void *ant_ptr) {
ant& ant = *((struct ant *) ant_ptr);
ant.run();
return NULL;
}
ant* ants;
void init_ants() {
for (size_t i = 0; i < n_ants; i++) {
ants[i].init();
ants[i].idx = i;
}
}
pthread_mutex_t mut;
void init_aco() {
pthread_mutex_init(&mut, NULL);
start = 0;
first_pass = true;
memset(pheromone_map, 0, sizeof(pheromone_map));
memset(ant_updated_pheromone_map, 0, sizeof(ant_updated_pheromone_map));
init_ants();
sh_dist = -1.0;
}
void populate_ant_updated_pheromone_map(ant& ant) {
for (size_t i = 0; i < ant.route.size(); i++) {
size_t j = (i + 1) % n_nodes;
double current_ph = ant_updated_pheromone_map[ant.route[i]][ant.route[j]];
double new_ph = pheromone_constant / ant.distance_travelled;
ant_updated_pheromone_map[ant.route[i]][ant.route[j]] =
ant_updated_pheromone_map[ant.route[j]][ant.route[i]] =
current_ph + new_ph;
}
}
void update_pheromone_map() {
for (size_t i = 0; i < n_nodes; i++) {
for (size_t j = 0; j < n_nodes; j++) {
pheromone_map[i][j] = (1 - pheromone_evaporation_coeff) *
pheromone_map[i][j] + ant_updated_pheromone_map[i][j];
}
}
}
void mainloop() {
for (size_t i = 0; i < n_iterations; i++) {
srand(i);
//cerr << "starting ants" << endl;
for (uint j = 0; j < n_ants; j++) {
pthread_create(&(ants[j].t_handle), NULL, ant_thread, &(ants[j]));
}
// cerr << "joining ants" << endl;
for (uint j = 0; j < n_ants; j++) {
pthread_join(ants[j].t_handle, NULL);
}
//cerr << "summing ants" << endl;
uint os = 0;
for (uint j = 0; j < n_ants; j++) {
os += ants[j].other;
populate_ant_updated_pheromone_map(ants[j]);
if (sh_dist < 0 || ants[j].distance_travelled < sh_dist) {
sh_dist = ants[j].distance_travelled;
sh_route = ants[j].route;
cerr << "new short distance is " << sh_dist << " ant " << j << endl;
}
}
update_pheromone_map();
first_pass = false;
init_ants();
memset(ant_updated_pheromone_map, 0, sizeof(ant_updated_pheromone_map));
/*double real = 0;
for (uint k = 0; k < n_nodes; k++) {
real += dist_matrix[sh_route[k]][sh_route[(k + 1) % n_nodes]];
}*/
cerr << "iteration " << i << ": dist " << sh_dist << endl;// << " os " << os << " rdist " << real << endl;
/*
uint nnz = 0;
double sum = 0, min = 1.0/0.0, max = -1.0/0.0;
for (int i = 0; i < n_nodes; i++) {
for (int j = 0; j < n_nodes - 1; j++) {
if (pheromone_map[i][j] != 0.0) nnz++;
sum += pheromone_map[i][j];
if (min > pheromone_map[i][j]) min = pheromone_map[i][j];
if (max < pheromone_map[i][j]) max = pheromone_map[i][j];
}
}
cerr << "phmap: avg " << sum / (double) (n_nodes * n_nodes) << " min " << min << " max " << max << " nnz " << nnz << endl;*/
}
}
uint two_opt() {
uint swaps = 0;
for (int i = 0; i < n_nodes - 1; i++) {
for (int j = i+2; j < n_nodes; j++) {
size_t ip = i == 0 ? (n_nodes - 1) : (i - 1);
size_t ei = sh_route[i], ej = sh_route[j], eii = sh_route[ip],
ejj = sh_route[j];
double new_dist = sh_dist - dist_matrix[eii][ei] - dist_matrix[ejj][ej]
+ dist_matrix[ei][ej] + dist_matrix[ejj][eii];
if (new_dist < sh_dist) {
//cerr << "2opt " << i << " " << j << ": " << new_dist << endl;
sh_dist = new_dist;
reverse(sh_route.begin() + i, sh_route.begin() + j);
swaps++;
}
}
}
return swaps;
}
uint two_five_opt() {
uint swaps = 0;
for (int i = 0; i < n_nodes - 2; i++) {
for (int j = i+2; j < n_nodes; j++) {
size_t ip = i == 0 ? (n_nodes - 1) : (i - 1);
size_t x1 = sh_route[ip];
size_t x2 = sh_route[i];
size_t x3 = sh_route[i+1];
size_t y3 = sh_route[j-2];
size_t y1 = sh_route[j-1];
size_t y2 = sh_route[j];
double var_a = sh_dist - dist_matrix[x2][x1] - dist_matrix[y2][y1]
+ dist_matrix[x1][y1] + dist_matrix[y2][x2];
double var_b = sh_dist - dist_matrix[x2][x1] - dist_matrix[y2][y1]
- dist_matrix[x2][x3] + dist_matrix[x2][y2]
+ dist_matrix[y1][x2] + dist_matrix[x1][x3];
double var_c = sh_dist - dist_matrix[x2][x1] - dist_matrix[y2][y1]
- dist_matrix[y1][y3] + dist_matrix[x1][y1]
+ dist_matrix[y1][x2] + dist_matrix[y3][y2];
if (var_a < sh_dist && var_a < var_b && var_a < var_c) {
//cerr << "25opt(a) " << i << " " << j << ": " << var_a << endl;
sh_dist = var_a;
reverse(sh_route.begin() + i, sh_route.begin() + j);
swaps++;
} else if (var_b < sh_dist && var_b < var_a && var_b < var_c) {
//cerr << "25opt(b) " << i << " " << j << ": " << var_b << endl;
//cerr << vector<uint>(sh_route.begin() + i - 1, sh_route.begin() + j + 1) << endl;
for (int k = i; k < j - 1; k++) {
sh_route[k] = sh_route[k + 1];
}
sh_route[j - 1] = x2;
//cerr << vector<uint>(sh_route.begin() + i - 1, sh_route.begin() + j + 1) << endl;
sh_dist = var_b;
swaps++;
} else if (var_c < sh_dist && var_c < var_a && var_c < var_b) {
//cerr << "25opt(c) " << i << " " << j << ": " << var_c << endl;
//cerr << vector<uint>(sh_route.begin() + i - 1, sh_route.begin() + j + 1) << endl;
for (int k = j - 2; k >= i; k--) {
sh_route[k + 1] = sh_route[k];
}
sh_route[i] = y1;
//cerr << vector<uint>(sh_route.begin() + i - 1, sh_route.begin() + j + 1) << endl;
sh_dist = var_c;
swaps++;
}
}
}
return swaps;
}
#define buffersize 100000
int main(int argc, char** argv) {
if (argc < 8) {
cerr << argv[0] << " [n_nodes] [n_iter] [n_ants] [alpha] [beta] [evap] [weight]" << endl;
return 1;
}
n_nodes = atoi(argv[1]);
n_iterations = atoi(argv[2]);
n_ants = atoi(argv[3]);
sscanf(argv[4], "%lf", &alpha);
sscanf(argv[5], "%lf", &beta);
sscanf(argv[6], "%lf", &pheromone_evaporation_coeff);
sscanf(argv[7], "%lf", &pheromone_constant);
ant ants_arr[n_ants];
ants = ants_arr;
cerr << n_nodes << endl;
char * pch;
int row = 0, column = 0;
char buffer[buffersize];
for (size_t i = 0; i < n_nodes; i++) {
fgets(buffer, buffersize, stdin);
pch = strtok(buffer, " ");
column = 0;
while (pch != NULL) {
sscanf(pch, "%lf", &(dist_matrix[row][column]));
pch = strtok(NULL, " ");
column++;
}
row++;
}
cerr << "reading done" << endl;
/*uint nnz = 0;
for (int i = 0; i < n_nodes; i++) {
for (int j = 0; j < n_nodes - 1; j++) {
if (dist_matrix[i][j] != 0.0) nnz++;
}
}
cerr << "dist: nnz " << nnz << endl;*/
init_aco();
// scan and parse
mainloop();
//for (uint k = 0; k < n_nodes; k++) {
// cerr << "p: " << sh_route[k] << ": " << dist_matrix[sh_route[k]][sh_route[(k + 1) % n_nodes]] << endl;
//}
cerr << "pre-optimization length: " << sh_dist << endl;
uint i = 0;
uint j = 0;
do {
//for (i = 0; i < 50; i++) {
//cerr << "2opt round " << i << endl;
//if(two_opt() == 0) break;
//}
for (j = 0; j < 50; j++) {
//cerr << "25opt round " << j << endl;
if(two_five_opt() == 0) break;
}
cerr << "optimizing length: " << sh_dist << endl;
} while (i > 0 || j > 0);
cerr << "optimized length: " << sh_dist << endl;
cout << sh_route << endl;
}

48
run.py
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@ -1,13 +1,17 @@
import glob
import pandas as pd
#import pandas as pd
from src.io_tsp import ProblemInstance
from src.TSP_solver import TSPSolver, available_improvers, available_solvers
import numpy as np
def use_solver_to_compute_solution(solver, improve, index, results, name, verbose, show_plots):
solver.bind(improve)
#solver.bind(improve)
# solver.bind("2-opt")
# solver.bind("2.5-opt")
solver.compute_solution(return_value=False, verbose=verbose)
# solver.pop()
# solver.pop()
if verbose:
print(f"the total length for the solution found is {solver.found_length}",
@ -23,8 +27,10 @@ def use_solver_to_compute_solution(solver, improve, index, results, name, verbos
def run(show_plots=False, verbose=False):
# problems = glob.glob('./problems/*.tsp')
problems = ["./problems/eil76.tsp"]
problems = glob.glob('./problems/*.tsp')
problems = ["./problems/fl1577.tsp"]
solvers_names = available_solvers.keys()
improvers_names = available_improvers.keys()
results = []
@ -36,19 +42,22 @@ def run(show_plots=False, verbose=False):
if show_plots:
prob_instance.plot_data()
for solver_name in solvers_names:
for improve in improvers_names:
solver = TSPSolver(solver_name, prob_instance)
use_solver_to_compute_solution(solver, improve, index, results, problem_path, verbose, show_plots)
for improve2 in [j for j in improvers_names if j not in [improve]]:
use_solver_to_compute_solution(solver, improve2, index, results, problem_path, verbose, show_plots)
for improve3 in [j for j in improvers_names if j not in [improve, improve2]]:
use_solver_to_compute_solution(solver, improve3, index, results, problem_path, verbose,
show_plots)
solver.pop()
solver.pop()
solver = TSPSolver(solver_name, prob_instance)
use_solver_to_compute_solution(solver, None, index, results, problem_path, verbose, show_plots)
# for improve in improvers_names:
# solver = TSPSolver(solver_name, prob_instance)
# use_solver_to_compute_solution(solver, improve, index, results, problem_path, verbose, show_plots)
# for improve2 in [j for j in improvers_names if j not in [improve]]:
# use_solver_to_compute_solution(solver, improve2, index, results, problem_path, verbose, show_plots)
#
# for improve3 in [j for j in improvers_names if j not in [improve, improve2]]:
# use_solver_to_compute_solution(solver, improve3, index, results, problem_path, verbose,
# show_plots)
# solver.pop()
#
# solver.pop()
if prob_instance.exist_opt and show_plots:
solver = TSPSolver("optimal", prob_instance)
@ -56,11 +65,12 @@ def run(show_plots=False, verbose=False):
solver.solution = np.concatenate([prob_instance.optimal_tour, [prob_instance.optimal_tour[0]]])
solver.plot_solution()
index = pd.MultiIndex.from_tuples(index, names=['problem', 'method'])
#index = pd.MultiIndex.from_tuples(index, names=['problem', 'method'])
return pd.DataFrame(results, index=index, columns=["tour length", "optimal solution", "gap", "time to solve"])
return None
#return pd.DataFrame(results, index=index, columns=["tour length", "optimal solution", "gap", "time to solve"])
if __name__ == '__main__':
df = run(show_plots=False, verbose=True)
df = run(show_plots=True, verbose=True)
df.to_csv("./results.csv")

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@ -6,17 +6,23 @@ from src.two_opt import loop2opt
from src.two_dot_five_opt import loop2dot5opt
from src.simulated_annealing import sa
from src.constructive_algorithms import random_method, nearest_neighbor, best_nearest_neighbor, multi_fragment_mf
from src.ant_colony import ant_colony_opt
available_solvers = {"random": random_method,
"nearest_neighbors": nearest_neighbor,
"best_nn": best_nearest_neighbor,
"multi_fragment": multi_fragment_mf
}
# available_solvers = {"random": random_method,
# "nearest_neighbors": nearest_neighbor,
# "best_nn": best_nearest_neighbor,
# "multi_fragment": multi_fragment_mf
# }
available_improvers = {"2-opt": loop2opt,
"2.5-opt": loop2dot5opt,
"simulated_annealing": sa}
# available_solvers = {}
# for i in range(1, 10):
# for j in range(1, 10):
# available_solvers["aco_" + str(i) + "_" + str(j)] = ant_colony_opt(i/10, j)
available_solvers = {"aco": ant_colony_opt}
class TSPSolver:
def __init__(self, algorithm_name, problem_instance, passed_avail_solvers=None, passed_avail_improvers=None):
@ -52,14 +58,14 @@ class TSPSolver:
print(f"### solving with {self.algorithms} ####")
start_time = t()
self.solution = self.available_solvers[self.algorithms[0]](self.problem_instance)
if self.check_if_solution_is_valid():
if not self.check_if_solution_is_valid():
print(f"Error the solution of {self.algorithm_name} for problem {self.problem_instance.name} is not valid")
if return_value:
return False
for i in range(1, len(self.algorithms)):
improver = self.algorithms[i]
self.solution = self.available_improvers[improver](self.solution, self.problem_instance)
if self.check_if_solution_is_valid():
if not self.check_if_solution_is_valid():
print(
f"Error the solution of {self.algorithm_name} with {improver} for problem {self.problem_instance.name} is not valid")
if return_value:

55
src/ant_colony.py Normal file
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@ -0,0 +1,55 @@
from src.io_tsp import ProblemInstance
import os
# OOT = out-of-time
# Run #0 unknown
# Run #1
# alpha = 0.5, beta = 7, evap = 0.5, weight = instance.best_sol
# if instance.nPoints > 1000: ants = 550 loops = 15
# elif instance.nPoints > 195: ants = 1000 loops = 55
# else: ants = 2500 loops = 150
# pr439=112263 pcb442=53699 d198=16199 fl1577=<OOT> ch130=6332 u1060=247703
# kroA100=21737 eil76=554 rat783=<OOT> lin318=45580
# Run #2
# alpha, beta, evap, weight = (0.9, 8, 0.4, 100_000)
# ants, loops = (900, 6) if instance.nPoints > 1100 \
# else (600, 15) if instance.nPoints > 1000 \
# else (750, 30) if instance.nPoints > 700 \
# else (975, 40) if instance.nPoints > 500 \
# else (1000, 50) if instance.nPoints > 300 \
# else (1100, 70) if instance.nPoints > 195 else (2700, 140)
# pr439=111322 pcb442=52176 d198=16177 ch130=6269 u1060=246085
# kroA100=21665 eil76=550 lin318=43675
# Separate run: fl1577=24238 (132s) rat783=9389 (174s)
dir = "/Users/maggicl/Git/AI2020BsC/c_prob/"
def ant_colony_opt(instance):
fname = dir + instance.name + ".txt"
# write .mat file for C++
if not os.path.exists(fname):
with open(fname, "w") as f:
for i in range(instance.nPoints):
print(" ".join(map(str, instance.dist_matrix[i])), file=f)
alpha, beta, evap, weight = (0.9, 8, 0.4, 100_000)
ants, loops = (1000,7) if instance.nPoints > 1100 \
else (600,15) if instance.nPoints > 1000 \
else (750,30) if instance.nPoints > 700 \
else (975,40) if instance.nPoints > 500 \
else (1000,50) if instance.nPoints > 300 \
else (1100,70) if instance.nPoints > 195 else (2700, 140)
# Call C++ program
cmd = dir + "aco " + str(instance.nPoints) + " " + str(loops) + " " + str(ants) + \
" " + str(alpha) + " " + str(beta) + " " + str(evap) + " " + str(weight) +" < " + fname + " &2>/dev/null"
print(cmd)
solution = eval(os.popen(cmd).read())
solution.append(solution[0])
return solution
if __name__ == "__main__":
ant_colony_opt(ProblemInstance("../problems/eil76.tsp"))

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@ -2,13 +2,11 @@ import numpy as np
from src.utils import compute_length
def random_method(instance_):
n = int(instance_.nPoints)
solution = np.random.choice(np.arange(n), size=n, replace=False)
return np.concatenate([solution, [solution[0]]])
def nearest_neighbor(instance_, starting_node=0):
dist_matrix = np.copy(instance_.dist_matrix)
n = int(instance_.nPoints)

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@ -27,7 +27,8 @@ def step2dot5opt(solution, matrix_dist, distance):
uncrosses += 1
tsp_sequence = sequences[best_method]
distance = best_len
# print(distance, best_method, [twoOpt_len, first_shift_len, second_shift_len])
print(i, j, best_len)
#print(distance, best_method, [twoOpt_len, first_shift_len, second_shift_len])
return tsp_sequence, distance, uncrosses
@ -62,7 +63,7 @@ def shift_gain2(i, j, tsp_sequence, matrix_dist):
return - old_link_len + changed_links_len
def loop2dot5opt(solution, instance, max_num_of_changes=10000):
def loop2dot5opt(solution, instance, max_num_of_changes=2500):
matrix_dist = instance.dist_matrix
actual_len = compute_length(solution, matrix_dist)
new_tsp_sequence = np.copy(np.array(solution))

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@ -2,7 +2,6 @@ import numpy as np
from src.utils import compute_length
def step2opt(solution, matrix_dist, distance):
seq_length = len(solution) - 1
tsp_sequence = np.array(solution)
@ -26,7 +25,7 @@ def swap2opt(tsp_sequence, i, j):
def gain(i, j, tsp_sequence, matrix_dist):
old_link_len = (matrix_dist[tsp_sequence[i], tsp_sequence[i - 1]] + matrix_dist[
tsp_sequence[j], tsp_sequence[j + 1]])
tsp_sequence[j], tsp_sequence[j + 1]])x
changed_links_len = (matrix_dist[tsp_sequence[j], tsp_sequence[i - 1]] + matrix_dist[
tsp_sequence[i], tsp_sequence[j + 1]])
return - old_link_len + changed_links_len