排隊(duì)系統(tǒng)仿真 包含C

1、排隊(duì)系統(tǒng)仿真實(shí)驗(yàn)1. 實(shí)驗(yàn)?zāi)康碾x散事件系統(tǒng)大量存在于現(xiàn)實(shí)生活中。離散事件系統(tǒng)往往是隨機(jī)的，具有復(fù)雜的變化關(guān)系，難以用常規(guī)的微分方程、差分方程等模型來(lái)描述，計(jì)算機(jī)仿真技術(shù)是解決這類問題的有效手段。排隊(duì)系統(tǒng)是一種非常重要的離散事件系統(tǒng)，也是最早研究的離散事件系統(tǒng)。本實(shí)驗(yàn)通過設(shè)計(jì)一種最簡(jiǎn)單的單服務(wù)臺(tái)排隊(duì)系統(tǒng)仿真程序，深入理解排隊(duì)系統(tǒng)的建模與仿真方法，掌握排隊(duì)系統(tǒng)仿真的基本步驟和程序設(shè)計(jì)技術(shù)，了解離散事件系統(tǒng)仿真的一般原理。2. 排隊(duì)系統(tǒng)仿真程序功能模擬一個(gè)單服務(wù)臺(tái)單隊(duì)列排隊(duì)系統(tǒng)的運(yùn)行過程，完成一定數(shù)量活動(dòng)實(shí)體的服務(wù)過程，輸出排隊(duì)系統(tǒng)的常用統(tǒng)計(jì)指標(biāo)。仿真運(yùn)行時(shí)間（可由活動(dòng)實(shí)體數(shù)確定）、活動(dòng)實(shí)體到達(dá)平均

2、時(shí)間間隔、平均服務(wù)時(shí)間作為參數(shù)在程序運(yùn)行時(shí)輸入。3. 關(guān)鍵技術(shù)（1）隨機(jī)數(shù)發(fā)生器乘同余法遞推公式：程序中采用：（2）隨機(jī)變量的產(chǎn)生變換抽樣法指數(shù)分布隨機(jī)變量的產(chǎn)生：其中，為到達(dá)（或服務(wù)）速率，1/到達(dá)時(shí)間平均間隔（或平均服務(wù)時(shí)間），u為隨機(jī)數(shù)。（3）排隊(duì)、到達(dá)、服務(wù)模式排隊(duì)規(guī)則：先到先服務(wù)（fifo）；到達(dá)模式：泊松到達(dá)，即相鄰兩個(gè)顧客到達(dá)的時(shí)間間隔服從指數(shù)分布；服務(wù)模式：服務(wù)臺(tái)為活動(dòng)實(shí)體提供服務(wù)的時(shí)間是隨機(jī)的，服從指數(shù)分布。（4）常用統(tǒng)計(jì)性能指標(biāo)計(jì)算平均延誤時(shí)間：其中，di為第i個(gè)活動(dòng)實(shí)體在隊(duì)列中耽誤的時(shí)間。平均滯留時(shí)間：其中，wi為第i個(gè)活動(dòng)實(shí)體在系統(tǒng)中滯留的時(shí)間，si為第i個(gè)活動(dòng)實(shí)體接受

3、服務(wù)臺(tái)服務(wù)的時(shí)間。平均隊(duì)長(zhǎng)：其中，q(t)為t時(shí)刻系統(tǒng)中隊(duì)列的長(zhǎng)度。平均實(shí)體數(shù)：其中，l(t)為t時(shí)刻系統(tǒng)中的活動(dòng)實(shí)體數(shù)，q(t)為t時(shí)刻隊(duì)列的長(zhǎng)度，s(t)為t時(shí)刻接受服務(wù)臺(tái)服務(wù)的活動(dòng)實(shí)體數(shù)。4. 程序架構(gòu)（1）基本模塊void initialize(void); /*變量初始化*/void timing(void);/*時(shí)間調(diào)度*/void arrive(void);/*到達(dá)事件處理*/void depart(void);/*離開事件處理*/void report(void);/*統(tǒng)計(jì)量輸出*/void update_time_avg_stats(void);/*統(tǒng)計(jì)量的更新*/float

4、 expon(float mean);/*指數(shù)分布隨機(jī)變量的變換抽樣法*/（2）程序流程（main()函數(shù)）（3）到達(dá)事件處理流程（arrive()函數(shù)）（4）離開事件處理流程（depart()函數(shù)）5. 程序設(shè)計(jì)（1）定義#include #include /*#include lcgrand.h header file for random-number generator. */#define q_limit 100 /* limit on queue length. */#define busy 1 /* mnemonics for servers being busy */#defi

5、ne idle 0 /* and idle. */int next_event_type, num_custs_delayed, num_delays_required, num_events, num_in_q, server_status;float area_num_in_q, area_server_status, mean_interarrival, mean_service, sim_time, time_arrivalq_limit + 1, time_last_event, time_next_event3, total_of_delays;file *infile, *out

6、file;float lcgrand(int stream);void initialize(void);void timing(void);void arrive(void);void depart(void);void report(void);void update_time_avg_stats(void);float expon(float mean);（2）主程序main() /* main function. */ /* open input and output files. */ infile = fopen(mm1.in, r); outfile = fopen(mm1.ou

7、t, w); /* specify the number of events for the timing function. */ num_events = 2; /* read input parameters. */ fscanf(infile, %f %f %d, &mean_interarrival, &mean_service, &num_delays_required); /* write report heading and input parameters. */ fprintf(outfile, single-server queueing systemnn); fprin

8、tf(outfile, mean interarrival time%11.3f minutesnn, mean_interarrival); fprintf(outfile, mean service time%16.3f minutesnn, mean_service); fprintf(outfile, number of customers%14dnn, num_delays_required); /* initialize the simulation. */ initialize(); /* run the simulation while more delays are stil

9、l needed. */ while (num_custs_delayed num_delays_required) /* determine the next event. */ timing(); /* update time-average statistical accumulators. */ update_time_avg_stats(); /* invoke the appropriate event function. */ switch (next_event_type) case 1: arrive(); break; case 2: depart(); break; /*

10、 invoke the report generator and end the simulation. */ report(); fclose(infile); fclose(outfile); return 0;（3）初始化函數(shù)void initialize(void) /* initialization function. */ /* initialize the simulation clock. */ sim_time = 0.0; /* initialize the state variables. */ server_status = idle; num_in_q = 0; ti

11、me_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_ne

12、xt_event1 = sim_time + expon(mean_interarrival); time_next_event2 = 1.0e+30;（4）時(shí)間調(diào)度函數(shù)void timing(void) /* timing function. */ int i; float min_time_next_event = 1.0e+29; next_event_type = 0; /* determine the event type of the next event to occur. */ for (i = 1; i = num_events; +i) if (time_next_even

13、ti 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); /* there is still room in the queue, so store the time of arrival of the arriving customer at the (new) end of time_arrival. */

14、time_arrivalnum_in_q = 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 += delay; /* increment the number of customers delayed, and make

15、server busy. */ +num_custs_delayed; server_status = busy; /* schedule a departure (service completion). */ time_next_event2 = sim_time + expon(mean_service); （6）離開事件處理函數(shù)void depart(void) /* departure event function. */ int i; float delay; /* check to see whether the queue is empty. */ if (num_in_q =

16、 0) /* the queue is empty so make the server idle and eliminate the departure (service completion) event from consideration. */ server_status = idle; time_next_event2 = 1.0e+30; else /* the queue is nonempty, so decrement the number of customers in queue. */ -num_in_q; /* compute the delay of the customer who is beginning service and update the total delay accumulator. */ delay = sim_time - time_arrival1; total_of_delays += delay; /* increment the number of customers delayed, and schedule departure. */ +num_custs_delayed; time_next_event2 = sim_time + expon(mean_service);