% matlab code to plot minimum-cost network;

% loads the data file mincost.dat into a matrix ex2.
load mincost.dat

% move it to A
A = mincost;

% figure number of arcs to plot
N = size(A,1);

% figure number of nodes (assumed numbered as integers, starting at zero)
     nodes = max(max(A(:,1:2))) + 1;

% pi = 4*atan(1.0);

% what's the biggest flow?
maxflow = max(A(:,3));

clf;
figure(1);

inx=0:nodes-1;
x = cos(inx*2*pi/nodes);
y = sin(inx*2*pi/nodes);
scatter(x,y,100,[0 0 1]);
xt=1.1*x;
yt=1.1*y;
for i=1:nodes
  text(xt(i),yt(i),num2str(inx(i)));
end

% draw the flow lines: gray for arcs with no flow, shades of blue
% for arcs with flow (closer to dark blue for heavy flow)
for i=1:N,
  x = [cos(A(i,1)*2*pi/nodes), cos(A(i,2)*2*pi/nodes)];
  y = [sin(A(i,1)*2*pi/nodes), sin(A(i,2)*2*pi/nodes)];
  if A(i,3)==0
    colorarr = .9 * [1 1 1];
  else
    colorarr = [1-(A(i,3)/maxflow) 1-(A(i,3)/maxflow) 1];
  end
  line(x,y,'LineWidth',2,'Color',colorarr);
  if A(i,3) > 0
    xt = (x(1)+x(2))/2;
    yt = (y(1)+y(2))/2;
    text(xt,yt,num2str(A(i,3)));
  end
end

axis([-1.1 1.1 -1.1 1.1]);
axis square;
title('solution to mincost flow problem');