//============================================== file = mm1_csim_simple.c =====
//=  A simple CSIM simulation of an M/M/1 queueing system                     =
//=============================================================================
#include <stdio.h>      // Needed for printf()
#include "csim.h"       // Needed for CSIM18 stuff

//----- Defines ---------------------------------------------------------------
#define SIM_TIME 1.0e7  // Total simulation time in seconds

//----- Globals ---------------------------------------------------------------
FACILITY Server;        // Declaration of CSIM Server facility

//----- Prototypes ------------------------------------------------------------
void generate(double lambda, double mu);  // Customer generator
void queue1(double service_time);         // Single server queue

//=============================================================================
//==  Main program                                                           ==
//=============================================================================
void sim(void)
{
  double   lambda;      // Mean arrival rate (cust/sec)
  double   mu;          // Mean service rate (cust/sec)

  // Create the simulation
  create("sim");

  // CSIM initializations
  Server = facility("Server");

  // Parameter initializations
  lambda = 0.5;
  mu = 1.0;

  // Initiate generate function and hold for SIM_TIME
  generate(lambda, mu);
  hold(SIM_TIME);

  // Output results
  report();
}

//=============================================================================
//==  Function to generate Poisson customers                                 ==
//=============================================================================
void generate(double lambda, double mu)
{
  double   interarrival_time;    // Interarrival time to next send
  double   service_time;         // Service time for this customer

  create("generate");

  // Loop forever to create customers
  while(1)
  {
    // Pull an interarrival time and hold for it
    interarrival_time = exponential(1.0 / lambda);
    hold(interarrival_time);

    // Pull a service time and then send the customer to the queue
    service_time = exponential(1.0 / mu);
    queue1(service_time);
  }
}

//=============================================================================
//==  Function for single server queue                                       ==
//=============================================================================
void queue1(double service_time)
{
  create("queue1");

  // Reserve, hold, and release server
  reserve(Server);
  hold(service_time);
  release(Server);
}