51 lines
1.8 KiB
Java
51 lines
1.8 KiB
Java
//: concurrency/FastSimulation.java
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import java.util.concurrent.*;
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import java.util.concurrent.atomic.*;
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import java.util.*;
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import static net.mindview.util.Print.*;
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public class FastSimulation {
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static final int N_ELEMENTS = 100000;
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static final int N_GENES = 30;
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static final int N_EVOLVERS = 50;
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static final AtomicInteger[][] GRID =
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new AtomicInteger[N_ELEMENTS][N_GENES];
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static Random rand = new Random(47);
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static class Evolver implements Runnable {
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public void run() {
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while(!Thread.interrupted()) {
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// Randomly select an element to work on:
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int element = rand.nextInt(N_ELEMENTS);
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for(int i = 0; i < N_GENES; i++) {
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int previous = element - 1;
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if(previous < 0) previous = N_ELEMENTS - 1;
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int next = element + 1;
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if(next >= N_ELEMENTS) next = 0;
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int oldvalue = GRID[element][i].get();
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// Perform some kind of modeling calculation:
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int newvalue = oldvalue +
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GRID[previous][i].get() + GRID[next][i].get();
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newvalue /= 3; // Average the three values
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if(!GRID[element][i]
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.compareAndSet(oldvalue, newvalue)) {
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// Policy here to deal with failure. Here, we
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// just report it and ignore it; our model
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// will eventually deal with it.
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print("Old value changed from " + oldvalue);
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}
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}
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}
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}
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}
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public static void main(String[] args) throws Exception {
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ExecutorService exec = Executors.newCachedThreadPool();
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for(int i = 0; i < N_ELEMENTS; i++)
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for(int j = 0; j < N_GENES; j++)
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GRID[i][j] = new AtomicInteger(rand.nextInt(1000));
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for(int i = 0; i < N_EVOLVERS; i++)
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exec.execute(new Evolver());
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TimeUnit.SECONDS.sleep(5);
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exec.shutdownNow();
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}
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} /* (Execute to see output) *///:~
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