M/M/1排队系统性能仿真代码（MATLAB）
可能有点儿乱啊~~嘿嘿%mm1 simulation in matlab
clc;clear;ST_Idle=0;
ST_Busy=1;EV_NULL=0;
EV_Arrive=1;
EV_Depart=2;
EV_LEN=3;Q_LIMIT=1000;% next_event_type=[];
% num_custs_delayed=[];
% num_delays_required=[];
% num_events=[];
% num_in_q=[];
% server_status=[];
% area_num_in_q=[];
% area_server_status=[];
% mean_interarrival=[];
% mean_service=[];
% sim_time=[];
% time_last_event=[];
% total_of_delays=[];
%
time_arrival=[]; %到达时刻time_next_event=zeros(1,EV_LEN);
%仿真参数
num_events=EV_LEN-1;
mean_interarrival=1;
mean_service=.5;
num_delays_required=2000; %outfile=fopen('mm1.txt','w');
fprintf(outfile, 'Single-server queueing system\n\n');
fprintf(outfile, 'Mean interarrival time%11.3f minutes\n\n',mean_interarrival);
fprintf(outfile, 'Mean service time%16.3f minutes\n\n', mean_service);
fprintf(outfile, 'Number of customers%14d\n\n', num_delays_required); %%%%%%%%%%%%%part1
sim_time=0.0;
% /* Initialize the state variables. */ server_status = 0;%idle
num_in_q = 0;
time_last_event = 0.0;
% /* Initialize the statistical counters. */ num_custs_delayed = 0;
total_of_delays = 0.0;
area_num_in_q = 0.0;
area_server_status = 0.0;
% /* Initialize event list. Since no customers are present, the departure
% (service completion) event is eliminated from consideration. */
time_next_event(EV_Arrive) = sim_time + randexp(mean_interarrival);
time_next_event(EV_Depart) = 1.0e+230;
%%%%%%%%%%%%part2
while (num_custs_delayed < num_delays_required)
%Run the simulation while more delays are still needed.
%/* Determine the next event. */ min_time_next_event = 1.0e+290;
next_event_type = 0;
%/* Determine the event type of the next event to occur. */ for i = 1: num_events
if (time_next_event(i) < min_time_next_event)
min_time_next_event = time_next_event(i);
next_event_type = i;
end
end
%/* Check to see whether the event list is empty. */ if (next_event_type == 0)
%/* The event list is empty, so stop the simulation. */ fprintf(outfile, '\nEvent list empty at time %f', sim_time);
exit(1);
end
%/* The event list is not empty, so advance the simulation clock. */ sim_time = min_time_next_event;
%/* Update time-average statistical accumulators. */ double time_since_last_event;%/* Compute time since last event, and update last-event-time marker. */ time_since_last_event = sim_time - time_last_event;
time_last_event = sim_time;%/* Update area under number-in-queue function. */ area_num_in_q=area_num_in_q + num_in_q * time_since_last_event;%/* Update area under server-busy indicator function. */ area_server_status =area_server_status + server_status * time_since_last_event;
%/* Invoke the appropriate event function. */%%%%%%%%%%%%%arrival if(next_event_type==EV_Arrive)
double delay;
%/* Schedule next arrival. */ time_next_event(1) = sim_time + randexp(mean_interarrival);%/* Check to see whether server is busy. */ if (server_status == ST_Busy)
%/* Server is busy, so increment number of customers in queue. */ num_in_q=1+num_in_q;
%/* Check to see whether an overflow condition exists. */ if (num_in_q > Q_LIMIT)
%/* The queue has overflowed, so stop the simulation. */ fprintf(outfile, '\nOverflow of the array time_arrival at');
fprintf(outfile, ' time %f', sim_time);
exit(2);
end
%/* There is still room in the queue, so store the time of arrival of the arriving customer at the (new) end of time_arrival. */ time_arrival(length(time_arrival)+1)=sim_time; else
%/* Server is idle, so arriving customer has a delay of zero. (The following two statements are for program clarity
%and do not affect the results of the simulation.) */ delay = 0.0;
total_of_delays =total_of_delays + delay;
%/* Increment the number of customers delayed, and make server busy. */ num_custs_delayed = 1 + num_custs_delayed;
server_status = ST_Busy;
%/* Schedule a departure (service completion). */ time_next_event(EV_Depart) = sim_time + randexp(mean_service);
end % if (server_status == ST_Busy)
%%%%%%%%depart
else
double delay;%/* Check to see whether the queue is empty. */ if (num_in_q == 0) % /* The queue is empty so make the server idle and eliminate the departure (service completion) event from consideration. */ server_status = ST_Idle;
time_next_event(EV_Depart) = 1.0e+230;
else%/* The queue is nonempty, so decrement the number of customers in queue. */ num_in_q=num_in_q-1;%/* Compute the delay of the customer who is beginning service and update the total delay accumulator. */ delay = sim_time - time_arrival(1);
total_of_delays =total_of_delays + delay;%/* Increment the number of customers delayed, and schedule departure. */ num_custs_delayed = 1 + num_custs_delayed;
time_next_event(EV_Depart) = sim_time + randexp(mean_service);%/* Move each customer in queue (if any) up one place. */ tempForPop=time_arrival(2:length(time_arrival));
time_arrival=tempForPop;
end %if (num_in_q == 0)
end %if(next_event_type==EV_Arrive)
end %while
%%%%%%%%%% part 3
%/* Invoke the report generator and end the simulation. */ fprintf(outfile, '\n\nAverage delay in queue%11.3f minutes\n\n',total_of_delays / num_custs_delayed);
fprintf(outfile, 'Average number in queue%10.3f\n\n',area_num_in_q / sim_time);
fprintf(outfile, 'Server utilization%15.3f\n\n',area_server_status / sim_time);
fprintf(outfile, 'Time simulation ended%12.3f minutes', sim_time);
fclose(outfile); 看看~~~~谢谢楼主 资料发上来 最好加上 一点解释 让大家都那能理解一下 谢谢楼主 ~~学习学习 dddddddddddddddddddddddddddddddddddddddddddddd {:3_59:}看不懂~ 啊！！很好很强大啊！感谢楼主。。 高手啊！请教一下，B题第一问怎么做呀？ 没有矩阵币怎么办？。。。 好东西啊，就是要用仿真的
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