三、路径和最短问题:
设平面上有N个点,求一点,使得这个点到所有点距离之和最小。这里,取N=8。数据点是1~5的随机数。
Lingo:
model:
sets:
position/1..8/:x,y;
ab/1/:a,b;
endsets
data:
@text('E:\matlab7.0\work\data.txt')=x,y;!读入到matlab的工作空间中;
@text('E:\matlab7.0\work\data1.txt')=a,b;
enddata
x(1)=1+4*@rand(0.12345);
y(1)=1+4*@rand(0.25);
@for(position(i)|i#ge#2:x(i)=1+4*@rand(x(i-1)));!随机产生1~5中的8个点;
@for(position(i)|i#ge#2:y(i)=1+4*@rand(y(i-1)));
[obj]min=@sum(position(i)sqrt((x(i)-a(1))^2+(y(i)-b(1))^2));!目标函数;
@bnd(1,a(1),5);
@bnd(1,b(1),5);
end
matlab:
clear;
clc;
close all;
load('data.txt');
load('data1.txt');
hold on;
plot(data1(1),data1(2),'o','MarkerSize',15,'MarkerFaceColor','r');
plot(data(:,1),data(:,2),'or','MarkerSize',15,'MarkerFaceColor','b');
set(gcf,'Color','w');
set(gca,'FontSize',16)
grid off;
data1=repmat(data1,8,1);
P=[data1(:,1)';data(:,1)'];
Q=[data1(:,2)';data(:,2)'];
plot(P,Q,'g','LineWidth',2);
xlabel('x');
ylabel('y');
title('Solving the problem of the minimun distance of tne sum of all the blue points towards the being known red point.');
gtext(['The minimun distance is ',num2str(10.2685),'.'],'FontSize',16,'Color','r');