75 lines
2.4 KiB
Java
75 lines
2.4 KiB
Java
// concurrency/FastSimulation.java
|
|
// ©2016 MindView LLC: see Copyright.txt
|
|
import java.util.concurrent.*;
|
|
import java.util.concurrent.atomic.*;
|
|
import java.util.*;
|
|
|
|
public class FastSimulation {
|
|
static final int N_ELEMENTS = 100000;
|
|
static final int N_GENES = 30;
|
|
static final int N_EVOLVERS = 50;
|
|
static final AtomicInteger[][] GRID =
|
|
new AtomicInteger[N_ELEMENTS][N_GENES];
|
|
static Random rand = new Random(47);
|
|
static class Evolver implements Runnable {
|
|
@Override
|
|
public void run() {
|
|
while(!Thread.interrupted()) {
|
|
// Randomly select an element to work on:
|
|
int element = rand.nextInt(N_ELEMENTS);
|
|
for(int i = 0; i < N_GENES; i++) {
|
|
int previous = element - 1;
|
|
if(previous < 0) previous = N_ELEMENTS - 1;
|
|
int next = element + 1;
|
|
if(next >= N_ELEMENTS) next = 0;
|
|
int oldvalue = GRID[element][i].get();
|
|
// Perform some kind of modeling calculation:
|
|
int newvalue = oldvalue +
|
|
GRID[previous][i].get() + GRID[next][i].get();
|
|
newvalue /= 3; // Average the three values
|
|
if(!GRID[element][i]
|
|
.compareAndSet(oldvalue, newvalue)) {
|
|
// Policy here to deal with failure. Here, we
|
|
// just report it and ignore it; our model
|
|
// will eventually deal with it.
|
|
System.out.println("Old value changed from " + oldvalue);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
public static void main(String[] args) throws Exception {
|
|
ExecutorService exec = Executors.newCachedThreadPool();
|
|
for(int i = 0; i < N_ELEMENTS; i++)
|
|
for(int j = 0; j < N_GENES; j++)
|
|
GRID[i][j] = new AtomicInteger(rand.nextInt(1000));
|
|
for(int i = 0; i < N_EVOLVERS; i++)
|
|
exec.execute(new Evolver());
|
|
TimeUnit.SECONDS.sleep(5);
|
|
exec.shutdownNow();
|
|
}
|
|
}
|
|
/* Output: (First and last 10 Lines)
|
|
Old value changed from 542
|
|
Old value changed from 447
|
|
Old value changed from 446
|
|
Old value changed from 643
|
|
Old value changed from 419
|
|
Old value changed from 573
|
|
Old value changed from 668
|
|
Old value changed from 710
|
|
Old value changed from 800
|
|
Old value changed from 406
|
|
________...________...________...________...________
|
|
Old value changed from 458
|
|
Old value changed from 436
|
|
Old value changed from 475
|
|
Old value changed from 501
|
|
Old value changed from 526
|
|
Old value changed from 465
|
|
Old value changed from 467
|
|
Old value changed from 368
|
|
Old value changed from 404
|
|
Old value changed from 428
|
|
*/
|