Added AoModel to demos

Signed-off-by: pjs <pjs@alum.mit.edu>

demos/AoModel.rb

+#!/usr/bin/env ruby
+
+require 'rubygems'
+require 'simplekit'
+
+# Demonstration model of Operational Availability (Ao).
+
+class AoModel
+  include SimpleKit
+
+  # model state
+  attr_reader  :numAvailableJeeps,
+    :numAvailableMechanics,
+    :maintenanceQLength,
+    :breakdownQLength
+
+  # model parameters
+  attr_reader  :maxJeeps,
+    :maxMaintainers,
+    :breakdownRate,
+    :maintenanceCycleInDays,
+    :repairRate,
+    :haltTime
+
+  # Exponential random variate generator with specified rate.
+  def exponential(rate)
+    -Math.log(rand) / rate
+  end
+
+  # the actual model implementation...
+
+  # Constructor initializes the model parameters.
+  def initialize(maxJeeps, maxMaintainers, breakdownRate,
+                 maintenanceCycleInDays, meanRepairTime, haltTime)
+    @maxJeeps = maxJeeps
+    @maxMaintainers = maxMaintainers
+    @breakdownRate = breakdownRate
+    @maintenanceCycleInDays = maintenanceCycleInDays
+    @repairRate = 1.0 / meanRepairTime
+    @haltTime = haltTime
+  end
+
+  # init method kickstarts a simplekit model.  State variables are
+  # set to initial values, and some preliminary events get scheduled
+  def init
+    @numAvailableJeeps = @maxJeeps
+    @numAvailableMechanics = @maxMaintainers
+    @maintenanceQLength = 0
+    @breakdownQLength = 0
+    @numAvailableJeeps.times do |i|
+      breakdownTime = exponential(@breakdownRate)
+      if (breakdownTime <= @maintenanceCycleInDays)
+        schedule(:breakdown, breakdownTime)
+      else
+        schedule(:maintenance, @maintenanceCycleInDays)
+      end
+    end
+    schedule(:halt, @haltTime)
+    STDOUT.puts "DailyAoReport"
+    schedule(:dailyReport, 0.0)
+  end
+
+  # Event methods follow...
+
+  def dailyReport
+    STDOUT.printf "%d\n", @numAvailableJeeps
+    schedule(:dailyReport, 8.0)
+  end
+
+  def breakdown
+    @breakdownQLength += 1
+    @numAvailableJeeps -= 1
+    schedule(:beginBreakdownService, 0.0) if (@numAvailableMechanics > 0)
+  end
+
+  def maintenance
+    @maintenanceQLength += 1
+    @numAvailableJeeps -= 1
+    schedule(:beginMaintenanceService, 0.0) if (@numAvailableMechanics > 0)
+  end
+
+  def beginMaintenanceService
+    @maintenanceQLength -= 1
+    @numAvailableMechanics -= 1
+    if (rand <= 0.95)
+      schedule(:endService, (6.5 - rand) / 8.0)
+    else
+      schedule(:endService, exponential(@repairRate / 4.0))
+    end
+  end
+
+  def beginBreakdownService
+    @breakdownQLength -= 1
+    @numAvailableMechanics -= 1
+    if (rand <= 0.8)
+      schedule(:endService, exponential(@repairRate))
+    else
+      schedule(:endService, exponential(@repairRate / 4.0))
+    end
+  end
+
+  def endService
+    @numAvailableMechanics += 1
+    @numAvailableJeeps += 1
+    if (@maintenanceQLength > 0)
+      schedule(:beginMaintenanceService, 0.0)
+    else
+      schedule(:beginBreakdownService, 0.0) if (@breakdownQLength > 0)
+    end
+    breakdownTime = exponential(@breakdownRate)
+    if (breakdownTime <= @maintenanceCycleInDays)
+      schedule(:breakdown, breakdownTime)
+    else
+      schedule(:maintenance, @maintenanceCycleInDays)
+    end
+  end
+
+end
+
+# Run model based on command-line arguments...
+if (ARGV.length != 6)
+  STDERR.puts "\nMust supply six command-line arguments:\n"
+  STDERR.puts "\tInitial Stock level (int)"
+  STDERR.puts "\t#Maintenance personnel (int)"
+  STDERR.puts "\tNormal breakdown rate (double)"
+  STDERR.puts "\tMaintenance cycle length (int)"
+  STDERR.puts "\tMean repair time (double)"
+  STDERR.puts "\tNumber of days to run (int)"
+  STDERR.puts "\nExample: ruby AoModel.rb 50 2 0.01 90 3.0 50\n"
+else
+  maxJeeps = ARGV[0].to_i
+  maxMaintainers = ARGV[1].to_i
+  breakdownRate = ARGV[2].to_f
+  maintenanceCycleInDays = ARGV[3].to_i
+  meanRepairTime = ARGV[4].to_f
+  haltTimeInDays = ARGV[5].to_i
+  # Simulation.run(new AoModel(50, 2, 0.01, 90, 3.0, 8.0 * haltTimeInDays))
+  AoModel.new(maxJeeps, maxMaintainers, breakdownRate,
+              maintenanceCycleInDays, meanRepairTime, 8.0 * haltTimeInDays).run
+end