双圆道交通流CA模型Matlab程序.doc

%function rho, flux, vmean = ns2(rho, p, L, tmax)%注意：主函数一定不能像子函数一样以function开头。此程序为含控制按钮NS模型改编双车道，无换道。% NS: This script implements the Nagel Schreckenberg cellular automata based% traffic model. Car move forward governed by NS algorithm:% % 1. Acceleration. If the vehicle can speed up without hitting the speed % limit vmax it will add one to its velocity, vn - vn + 1. Otherwise, % the vehicle has constant speed, vn 鈫? vn.% 2. Collision prevention. If the distance between the vehicle and the car% ahead of it, dn, is less than or equal to vn , i.e. the nth vehicle% will collide if it doesnt slow down, then vn 鈫? dn 鈭? 1.% 3. Random slowing. Vehicles often slow for non-traffic reasons (cell % phones, coffee mugs, even laptops) and drivers occasionally make % irrational choices. With some probability pbrake, vn =? vn -1, % presuming vn 0.% 4. Vehicle movement. The vehicles are deterministically moved by their % velocities, xn - xn + vn .% USAGE: flux = ns(rho, p, L, tmax, isdraw)% rho = density of the traffic% p = probability of random braking% L = length of the load% tmax = number of the iterations% animation = if show the animation （动画）of the traffic% spacetime = if plot the space-time after the simuation ended.% flux = flux of the traffic% zhou lvwen: rho = 0.25; p = 0.25; L = 100; tmax = 100; i=0;%=%build the GUI%define the plot buttonplotbutton=uicontrol(style,pushbutton,. string,Run, . fontsize,12, . position,60,400,50,20, . callback, run=1;);%define the stop buttonerasebutton=uicontrol(style,pushbutton,. string,Stop, . fontsize,12, . position,120,400,50,20, . callback,freeze=1;);%=%define the Quit buttonquitbutton=uicontrol(style,pushbutton,. string,Quit, . fontsize,12, . position,180,400,50,20, . callback,stop=1;close;);%=vmax = 5; % maximun speed% place a distribution with densityncar = round(L*rho);rho = ncar/L;x1= sort(randsample(1:L, ncar);x2= sort(randsample(1:L, ncar);x=x1;x2;%randsample(1:L, ncar)，从1-100产生25个随机整数，sort 排序 默认升序v = vmax * ones(2,ncar); % start everyone initially at vmax h1,h2 = plotcirc(L,x,0.1); flux = 0; % number of cars that pass through the endvmean = 0;road = zeros(tmax, L);stop= 0; %wait for a quit button pushrun = 0; %wait for a draw freeze = 0; %wait for a freeze while (stop=0) if (run=1) if itmax i=i+1; % acceleration v = min(v+1, vmax); %collision prevention gaps = gaplength(x,L); % determine the space vehicles have to move v = min(v, gaps-1); % random speed drops vdrops = ( rand(2,ncar)L; % cars passed at time r x(passed) = x(passed) - L;% periodic boundary conditions flux = flux + sum(v/L); %flux = flux + sum(passed); vmean = vmean + mean(v); %自迭代一半后开始计算流量 road(i,x) = 1; h1,h2 = plotcirc(L,x,0.1,h1,h2); end end if (freeze=1) run = 0; freeze = 0; end xlabel(strcat(flux= ,num2str(mean(flux), . strcat(vmean = , num2str(mean(vmean),. strcat(i = ,num2str(i) drawnow %need this in the loop for controls to work end figure(2);imagesc(road);colormap(1,1,1;0,0,0);axis image;%实则就是将车辆的状况用图像表示出来，colormap(1,1,1;0,0,0)是将车辆表示为黑色。%function gaps = gaplength(x,L)% GAPLENGTH: determine the gaps between vehiclesncar = length(x(1,:);gaps=zeros(2, ncar);if ncar0 gaps = x(:,2:end 1) -x; gaps(gaps=0) = gaps(gaps=0)+L;end%function h1,h2 = plotcirc(L,x,dt,h1,h2)W = 0.05; R = 1;ncar = length(x(1,:);theta = (0-pi/L) : 2*pi/L : (2*pi+pi/L);xc = cos(theta); yc = sin(theta);xinner = (R-W/2)*xc; yinner = (R-W/2)*yc;xouter = (R+W/2)*xc; youter = (R+W/2)*yc;xouter1 = (R+1.5*W)*xc; youter1 = (R+1.5*W)*yc; if nargin = 3 color1 = randperm(ncar); color2 = randperm(ncar); xi = xinner(x(1,:); xinner(x(1,:)+1); xouter(x(1,:)+1); xouter(x(1,:); yi = yinner(x(1,:); yinner(x(1,:)+1); youter(x(1,:)+1); youter(x(1,:); xi1= xouter(x(2,:); xouter(x(2,:)+1);xouter1(x(2,:)+1); xouter1(x(2,:); yi1= youter(x(2,:); youter(x(2,:)+1);youter1(x(2,:)+1); youter1(x(2,:); h1 = fill(xi,yi, color1);hold on h2=fill(xi1,yi1, color2); plot(xinner,yinner, k, xouter,youter, k,xouter1,youter1, k,linewidth,1.5) plot(xinner;xouter;xouter1, yinner;youter;youter1,k,linewidth,1.5) axis image; axis(R+2*W)*-1 1 -1 1);set(gca, xtick, , ytick, );% 将坐标清除，比axis off使用好，else xi = xinner(x(1,:); xinner(x(1,:)+1); xouter(x(1,:)+1); xouter(x(1,:); yi = yinner(x(1,:); yinner(x(1,:)+1); youter(x(1,:)+1); youter(x(1,:); xi1= xouter(x(2,:); xouter(x(2,:)+1);xouter1(x(2,:)+1); xouter1(x(2,:); yi