Add examples

README.md

@@ -1,8 +1,7 @@
 # sim
-Discrete event simulation library, inspired by GPSS, to be used in Deno projects.
+Discrete event simulation library, inspired by GPSS and SimPy.
 
 ## Usage
-Deno import
 ```js
 import { Process, Sim, uniformInt } from "https://deno.land/x/[email protected]/mod.ts";
 
@@ -20,6 +19,8 @@ sim.generatePoisson(agent, 1 / 5); // generate one agent every 5 units of time
 sim.run(30); // start the simulation, and run it for 30 units of time
 ```
 
+Check the examples folder for other models.
+
 ## Current capabilities
 - Scheduling of events with simulated time
 - Resources, with impatience
@@ -28,6 +29,6 @@ sim.run(30); // start the simulation, and run it for 30 units of time
 - Basic analysis (multiple runs, ANOVA, etc.)
 - Basic charts (using Vega-Lite)
 
-## Intended
-- Better docs (for now, see tests)
+## TO-DO
+- More examples
 - Ability for processes to get more information about the simulated environment (resource stats, etc.)

examples/README.md

@@ -0,0 +1,3 @@
+## Examples
+
+The SimPy folder contains simulation models that try to reproduce some of the [SimPy example models](https://simpy.readthedocs.io/en/latest/examples/index.html).

examples/SimPy/bank_renege.ts

@@ -0,0 +1,59 @@
+/*
+Covers: Resources, Condition events
+
+A counter with a random service time and customers who renege.
+Based on https://simpy.readthedocs.io/en/latest/examples/bank_renege.html
+
+This example models a bank counter and customers arriving at random times.
+Each customer has a certain patience. She waits to get to the counter until she’s at the end of her tether.
+If she gets to the counter, she uses it for a while before releasing it.
+
+New customers are created by the source process every few time steps.
+*/
+
+import { PREEMPT, Process, Result, Sim, expovariate, uniform } from "../../mod.ts";
+
+const NEW_CUSTOMERS = 5  // Total number of customers
+const INTERVAL_CUSTOMERS = 10.0  // Generate new customers roughly every x seconds
+const MIN_PATIENCE = 1  // Min. customer patience
+const MAX_PATIENCE = 3  // Max. customer patience
+
+const sim = new Sim();
+
+const counter = sim.resource("Counter");
+
+function* source(_: number): Process {
+    for(let i=0; i<NEW_CUSTOMERS; ++i){
+        sim.spawn(customer);
+        yield expovariate(1 / INTERVAL_CUSTOMERS);
+    }
+}
+
+let customerId = 0;
+
+function* customer(_: number): Process {
+    const arrive = sim.time;
+    const name = `Customer 0${++customerId}`;
+    console.log(`${arrive.toFixed(4)} ${name}: Here I am`);
+    const req = yield counter.requestImpatient(impatience);
+    const wait = sim.time - arrive;
+    if(req == Result.OK){
+        console.log(`${sim.time.toFixed(4)} ${name}: Waited ${wait}`);
+        yield expovariate(1 / 12);
+        yield counter.release();
+        console.log(`${sim.time.toFixed(4)} ${name}: Finished`);
+    }
+    else{
+        console.log(`${sim.time.toFixed(4)} ${name}: RENEGED after ${wait}`);
+    }
+}
+
+function* impatience(_:number): Process {
+    const patience = uniform(MIN_PATIENCE, MAX_PATIENCE);
+    yield patience;
+    yield PREEMPT;
+}
+
+sim.spawn(source);
+console.log("Bank Renege");
+sim.run();

examples/SimPy/carwash.ts

@@ -0,0 +1,45 @@
+/*
+Carwash example.
+Based on https://simpy.readthedocs.io/en/latest/examples/carwash.html
+
+Covers: Waiting for other processes, Resources
+
+Scenario:
+  A carwash has a limited number of washing machines and defines
+  a washing processes that takes some (random) time.
+
+  Car processes arrive at the carwash at a random time. If one washing
+  machine is available, they start the washing process and wait for it
+  to finish. If not, they wait until they can use one.
+*/
+
+import { Sim, Process, uniformInt } from "../../mod.ts";
+
+const NUM_MACHINES = 2  // Number of machines in the carwash
+const WASHTIME = 5      // Minutes it takes to clean a car
+const T_INTER = 7       // Create a car every ~7 minutes
+const SIM_TIME = 20     // Simulation time in minutes
+
+const sim = new Sim();
+
+const machine = sim.resource("Machine", NUM_MACHINES);
+
+let carCount = 0;
+
+function* car(_: number): Process {
+    const name = `Car ${carCount++}`;
+    console.log(`${name} arrives at the carwash at ${sim.time.toFixed(2)}`);
+    yield machine.request();
+    console.log(`${name} enters the carwash at ${sim.time.toFixed(2)}`);
+    yield WASHTIME;
+    const pctDirt = uniformInt(50, 99);
+    console.log(`Carwash removed ${pctDirt}% of ${name}'s dirt`);
+    console.log(`${name} leaves the carwash at ${sim.time.toFixed(2)}`);
+    yield machine.release();
+}
+
+for(let i=0; i<4; ++i) sim.spawn(car);
+sim.generate(car, T_INTER, 2);
+
+console.log("Carwash");
+sim.run(SIM_TIME);