| 1 | package de.uka.ipd.sdq.simucomframework; |
| 2 | |
| 3 | import java.util.Random; |
| 4 | import java.util.concurrent.LinkedBlockingQueue; |
| 5 | |
| 6 | import org.apache.log4j.Logger; |
| 7 | |
| 8 | import de.uka.ipd.sdq.probfunction.math.IRandomGenerator; |
| 9 | |
| 10 | import de.uka.ipd.sdq.probfunction.math.apache.impl.MT19937RandomGenerator; |
| 11 | import de.uka.ipd.sdq.probfunction.math.random.IRandomStream; |
| 12 | import de.uka.ipd.sdq.simucomframework.variables.functions.LogNormDistFunction; |
| 13 | import de.uka.ipd.sdq.simucomframework.variables.functions.NormDistFunction; |
| 14 | |
| 15 | /** |
| 16 | * SimuComDefaultRandomNumberGenerator generates random numbers in a separate thread. |
| 17 | * SimuComDefaultRandomNumberGenerator currently implements the interface for |
| 18 | * random numbers needed by the prob function package. However, internally it |
| 19 | * relies on a random stream implementing the RandomStream interface from JSS. |
| 20 | * |
| 21 | * SimuComDefaultRandomNumberGenerator implements {@link RandomStream} as the |
| 22 | * functions like {@link LogNormDistFunction} and {@link NormDistFunction} in |
| 23 | * package de.uka.ipd.sdq.simucomframework.variables.functions. |
| 24 | * |
| 25 | * This class is optimized for multi-cores, thus speeding up simulation significantly for |
| 26 | * at least two cores. Here everything related to random numbers in SimuCom should be then localised, especially seed |
| 27 | * initialisation and the multi-threading stuff (which was - as always - deadlock |
| 28 | * prone while implementing). Also it locates the dependency to the [0..1] random |
| 29 | * number generator to a single place in the source (remember this needs to be |
| 30 | * changed to get away from GPL code...). |
| 31 | * |
| 32 | * @author Steffen Becker |
| 33 | * |
| 34 | */ |
| 35 | public class SimuComDefaultRandomNumberGenerator implements IRandomGenerator { |
| 36 | |
| 37 | private static final int MAX_PRODUCER_BUFFER_SIZE = 1000; |
| 38 | private static final Logger logger = |
| 39 | Logger.getLogger(SimuComDefaultRandomNumberGenerator.class.getName()); |
| 40 | private static long streamCounter = 0; |
| 41 | private long myID; |
| 42 | private final IRandomStream rndNumberGenerator; |
| 43 | private LinkedBlockingQueue<Double> producerQueue = new LinkedBlockingQueue<Double>(MAX_PRODUCER_BUFFER_SIZE); |
| 44 | private Thread producerThread; |
| 45 | private volatile boolean finished; |
| 46 | |
| 47 | public SimuComDefaultRandomNumberGenerator(long[] randomSeed){ |
| 48 | this.myID = streamCounter++; |
| 49 | this.finished = false; |
| 50 | |
| 51 | if (logger.isDebugEnabled()) { |
| 52 | logger.debug("Initialising random number generator! [Stream ID = "+myID+"]"); |
| 53 | } |
| 54 | rndNumberGenerator = new MT19937RandomGenerator();//new MRG32k3aRandomGenerator(); |
| 55 | initRandomSeed(randomSeed); |
| 56 | |
| 57 | this.producerThread = new Thread(new Runnable(){ |
| 58 | public void run() { |
| 59 | logger.debug("Random number producer started! [Stream ID = "+myID+"]"); |
| 60 | try { |
| 61 | while (!finished) { |
| 62 | producerQueue.put(rndNumberGenerator.nextDouble()); |
| 63 | } |
| 64 | } catch (InterruptedException e) { |
| 65 | logger.debug("Bad concurrency problem",e); |
| 66 | throw new RuntimeException("Unexpected interruption of concurrent threads"); |
| 67 | } |
| 68 | logger.debug("Random number producer stopped! [Stream ID = "+myID+"]"); |
| 69 | } |
| 70 | }); |
| 71 | producerThread.start(); |
| 72 | |
| 73 | if (logger.isDebugEnabled()) { |
| 74 | logger.debug("Random number stream initialised! [Stream ID = "+myID+"]"); |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * Set up seed of random number generator |
| 80 | * @param randomSeed The random number generator's seed. May be null for default initialisation |
| 81 | */ |
| 82 | private void initRandomSeed(long[] randomSeed) { |
| 83 | if (randomSeed != null) { |
| 84 | if (randomSeed.length == 6) { |
| 85 | if (logger.isDebugEnabled()) { |
| 86 | logger.debug("Setting fixed seed for random number generator! [Stream ID = "+myID+"]"); |
| 87 | for (int i=0; i<6; i++) { |
| 88 | logger.debug("Seed "+i+" = "+randomSeed[i]); |
| 89 | } |
| 90 | } |
| 91 | rndNumberGenerator.setSeed(randomSeed); |
| 92 | } |
| 93 | else { |
| 94 | throw new RuntimeException("Seed array must have length of six longs for initialising random number generator"); |
| 95 | } |
| 96 | } |
| 97 | else { |
| 98 | if (logger.isDebugEnabled()) { |
| 99 | logger.debug("Setting random seed for random number generator! [Stream ID = "+myID+"]"); |
| 100 | } |
| 101 | long[] myRandomSeed = new long[6]; |
| 102 | Random r = new Random(); |
| 103 | for (int i = 0; i < myRandomSeed.length; i++) { |
| 104 | myRandomSeed[i] = r.nextInt(); |
| 105 | } |
| 106 | rndNumberGenerator.setSeed(myRandomSeed); |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Returns a (pseudo)random number from the uniform distribution over the interval (0, 1), using this stream, after advancing its state by one step. The generators programmed in SSJ never return the values 0 or 1. |
| 112 | * This method takes a previously generated random number from the asynchronously running generator thread. |
| 113 | */ |
| 114 | public double random() { |
| 115 | if (logger.isDebugEnabled()) { |
| 116 | logger.debug("Drawing a random number from random number stream ["+myID+"]!"); |
| 117 | } |
| 118 | double d; |
| 119 | try { |
| 120 | d = producerQueue.take(); |
| 121 | } catch (InterruptedException e) { |
| 122 | throw new RuntimeException("Unexpected interruption of concurrent threads"); |
| 123 | } |
| 124 | if (logger.isDebugEnabled()) { |
| 125 | logger.debug("Number is: "+d); |
| 126 | } |
| 127 | return d; |
| 128 | } |
| 129 | |
| 130 | public void dispose() { |
| 131 | finished = true; |
| 132 | producerQueue.clear(); |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * Generates n (pseudo)random numbers from the uniform distribution and stores them into the array u starting at index start. |
| 137 | * (doc from {@link RandomStream}) |
| 138 | * @param u - array that will contain the generated uniforms |
| 139 | * @param start - starting index, in the array u, to write uniforms from |
| 140 | * @param n - number of uniforms to generate |
| 141 | */ |
| 142 | public void nextArrayOfDouble(double[] u, int start, int n) { |
| 143 | for (int i = start; i < u.length && i - start < n; i++) { |
| 144 | u[i] = this.random(); |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * Generates n (pseudo)random numbers from the discrete uniform distribution over the |
| 150 | * integers {i, i + 1,..., j}, using this stream and stores the result in the |
| 151 | * array u starting at index start. (Calls nextInt n times.) |
| 152 | * (doc from {@link RandomStream} |
| 153 | * @param i - smallest integer that can be generated |
| 154 | * @param j - greatest integer that can be generated |
| 155 | * @param u - array that will contain the generated values |
| 156 | * @param start - starting index, in the array u, to write integers from |
| 157 | * @param n - number of values being generated |
| 158 | */ |
| 159 | public void nextArrayOfInt(int i, int j, int[] u, int start, |
| 160 | int n) { |
| 161 | for (int index = start; index < u.length && index - start < n; index++) { |
| 162 | u[index] = this.nextInt(i, j); |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | /** |
| 167 | * Returns a (pseudo)random number from the uniform distribution over the interval (0, 1), using this stream, after advancing its state by one step. The generators programmed in SSJ never return the values 0 or 1. |
| 168 | * Calls random() which takes a previously generated random number from the asynchronously running generator thread. |
| 169 | */ |
| 170 | public double nextDouble() { |
| 171 | return this.random(); |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Returns a (pseudo)random number from the discrete uniform distribution over the integers {i, i + 1,..., j}, using this stream. (Calls nextDouble once.) |
| 176 | * Copied from {@link RandomStreamBase}. |
| 177 | * @param i - smallest integer that can be generated |
| 178 | * @param j - greatest integer that can be generated |
| 179 | */ |
| 180 | public int nextInt(int i, int j) { |
| 181 | // copied from RandomStreamBase |
| 182 | return i + (int)(nextDouble() * (j - i + 1.0)); |
| 183 | } |
| 184 | |
| 185 | /** |
| 186 | * does nothing because this implementation does not support any substreams |
| 187 | */ |
| 188 | public void resetNextSubstream() { |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * does nothing because this implementation does not support any substreams |
| 193 | */ |
| 194 | public void resetStartStream() { |
| 195 | } |
| 196 | |
| 197 | |
| 198 | /** |
| 199 | * does nothing because this implementation does not support any substreams |
| 200 | */ |
| 201 | public void resetStartSubstream() { |
| 202 | } |
| 203 | |
| 204 | } |