September 2017 Update
This commit is contained in:
Ingy döt Net
parent
bba7bfd280
commit
ba8067c3b7
14570 changed files with 153136 additions and 63871 deletions
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@ -1,119 +0,0 @@
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import java.util.Arrays;
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import java.util.Random;
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public class AtomicUpdates
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{
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public static class Buckets
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{
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private final int[] data;
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public Buckets(int[] data)
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{
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this.data = data.clone();
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}
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public int getBucket(int index)
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{
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synchronized (data)
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{ return data[index]; }
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}
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public int transfer(int srcBucketIndex, int destBucketIndex, int amount)
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{
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if (amount == 0)
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return 0;
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// Negative transfers will happen in the opposite direction
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if (amount < 0)
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{
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int tempIndex = srcBucketIndex;
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srcBucketIndex = destBucketIndex;
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destBucketIndex = tempIndex;
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amount = -amount;
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}
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synchronized (data)
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{
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if (amount > data[srcBucketIndex])
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amount = data[srcBucketIndex];
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if (amount <= 0)
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return 0;
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data[srcBucketIndex] -= amount;
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data[destBucketIndex] += amount;
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return amount;
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}
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}
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public int[] getBuckets()
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{
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synchronized (data)
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{ return data.clone(); }
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}
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}
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public static int getTotal(int[] values)
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{
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int totalValue = 0;
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for (int i = values.length - 1; i >= 0; i--)
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totalValue += values[i];
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return totalValue;
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}
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public static void main(String[] args)
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{
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final int NUM_BUCKETS = 10;
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Random rnd = new Random();
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final int[] values = new int[NUM_BUCKETS];
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for (int i = 0; i < values.length; i++)
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values[i] = rnd.nextInt(10);
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System.out.println("Initial Array: " + getTotal(values) + " " + Arrays.toString(values));
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final Buckets buckets = new Buckets(values);
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new Thread(new Runnable() {
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public void run()
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{
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Random r = new Random();
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while (true)
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{
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int srcBucketIndex = r.nextInt(NUM_BUCKETS);
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int destBucketIndex = r.nextInt(NUM_BUCKETS);
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int amount = (buckets.getBucket(srcBucketIndex) - buckets.getBucket(destBucketIndex)) >> 1;
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if (amount != 0)
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buckets.transfer(srcBucketIndex, destBucketIndex, amount);
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}
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}
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}
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).start();
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new Thread(new Runnable() {
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public void run()
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{
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Random r = new Random();
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while (true)
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{
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int srcBucketIndex = r.nextInt(NUM_BUCKETS);
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int destBucketIndex = r.nextInt(NUM_BUCKETS);
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int srcBucketAmount = buckets.getBucket(srcBucketIndex);
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int destBucketAmount = buckets.getBucket(destBucketIndex);
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int amount = r.nextInt(srcBucketAmount + destBucketAmount + 1) - destBucketAmount;
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if (amount != 0)
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buckets.transfer(srcBucketIndex, destBucketIndex, amount);
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}
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}
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}
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).start();
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while (true)
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{
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long nextPrintTime = System.currentTimeMillis() + 3000;
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long curTime;
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while ((curTime = System.currentTimeMillis()) < nextPrintTime)
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{
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try
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{ Thread.sleep(nextPrintTime - curTime); }
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catch (InterruptedException e)
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{ }
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}
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int[] bucketValues = buckets.getBuckets();
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System.out.println("Current values: " + getTotal(bucketValues) + " " + Arrays.toString(bucketValues));
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}
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}
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}
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@ -1,186 +0,0 @@
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import java.util.Arrays;
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import java.util.Optional;
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import java.util.Random;
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import java.util.function.Consumer;
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import java.util.function.Function;
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import java.util.stream.IntStream;
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import java.util.stream.Stream;
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public interface Buckets {
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public static Buckets new_(int[] data) {
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return $.new_(data);
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}
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public static void main(String... arguments) {
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$.main(arguments);
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}
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public int[] getBuckets();
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public int getBucket(int index);
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public int transfer(int srcBucketIndex, int destBucketIndex, int amount);
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public enum $ {
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$$;
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private static Buckets new_(int[] data) {
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return (FunctionalBuckets) function -> {
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synchronized (data) {
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return Optional.of(data)
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.map(function)
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.filter(output -> output != data)
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.orElseGet(() -> data.clone())
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;
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}
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};
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}
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private static void main(String... arguments) {
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Stream.of(new Random())
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.parallel()
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.map(r -> r.ints($.NUM_BUCKETS, 0, NUM_BUCKETS))
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.map(IntStream::toArray)
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.peek(bucketValues -> Stream.of(bucketValues)
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.map(values -> "Initial values: " + getTotal(values) + " " + Arrays.toString(values))
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.forEach(System.out::println)
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)
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.map(Buckets::new_)
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.forEach(
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Stream.<Consumer<Buckets>>of(
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$::processBuckets,
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$::displayBuckets
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).reduce($ -> {}, Consumer::andThen)
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)
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;
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}
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@FunctionalInterface
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private static interface FunctionalBuckets extends Buckets {
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public Object untypedUseData(Function<int[], Object> function);
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@SuppressWarnings("unchecked")
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public default <OUTPUT> OUTPUT useData(Function<int[], OUTPUT> function) {
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return (OUTPUT) untypedUseData(function::apply);
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}
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@Override
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public default int[] getBuckets() {
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return useData(Function.<int[]>identity());
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}
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@Override
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public default int getBucket(int index) {
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return useData(data -> data[index]);
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}
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@Override
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public default int transfer(int originalSrcBucketIndex, int originalDestBucketIndex, int originalAmount) {
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return useData(data -> {
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int srcBucketIndex = originalSrcBucketIndex;
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int destBucketIndex = originalDestBucketIndex;
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int amount = originalAmount;
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if (amount == 0) {
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return 0;
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}
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// Negative transfers will happen in the opposite direction
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if (amount < 0) {
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int tempIndex = srcBucketIndex;
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srcBucketIndex = destBucketIndex;
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destBucketIndex = tempIndex;
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amount = -amount;
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}
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if (amount > data[srcBucketIndex]) {
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amount = data[srcBucketIndex];
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}
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if (amount <= 0) {
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return 0;
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}
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data[srcBucketIndex] -= amount;
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data[destBucketIndex] += amount;
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return amount;
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});
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}
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}
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private static final int NUM_BUCKETS = 10;
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private static final int PRINT_DELAY = 3_000;
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private static int getTotal(int[] values) {
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return Arrays.stream(values)
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.parallel()
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.sum()
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;
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}
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private static void equalizeBuckets(Buckets buckets) {
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Random r = new Random();
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while (true) {
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int srcBucketIndex = r.nextInt($.NUM_BUCKETS);
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int destBucketIndex = r.nextInt($.NUM_BUCKETS);
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Stream.of(srcBucketIndex, destBucketIndex)
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.map(buckets::getBucket)
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.reduce((srcBucketAmount, destBucketAmount) ->
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srcBucketAmount - destBucketAmount
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)
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.map(amount -> amount >> 1)
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.filter(amount -> amount != 0)
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.ifPresent(amount ->
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buckets.transfer(srcBucketIndex, destBucketIndex, amount)
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)
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;
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}
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}
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private static void randomizeBuckets (Buckets buckets) {
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Random r = new Random();
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while (true) {
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int srcBucketIndex = r.nextInt($.NUM_BUCKETS);
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int destBucketIndex = r.nextInt($.NUM_BUCKETS);
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Stream.of(srcBucketIndex, destBucketIndex)
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.map(buckets::getBucket)
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.reduce((srcBucketAmount, destBucketAmount) ->
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r.nextInt(srcBucketAmount + destBucketAmount + 1) - destBucketAmount
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)
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.filter(amount -> amount != 0)
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.ifPresent(amount ->
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buckets.transfer(srcBucketIndex, destBucketIndex, amount)
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)
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;
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}
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}
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private static Runnable run(Runnable runnable) {
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return runnable;
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}
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private static void processBuckets(Buckets buckets) {
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Stream.<Consumer<Buckets>>of(
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$::equalizeBuckets,
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$::randomizeBuckets
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)
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.parallel()
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.map(consumer -> run(() -> consumer.accept(buckets)))
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.map(Thread::new)
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.forEach(Thread::start)
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;
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}
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private static void displayBuckets(Buckets buckets) {
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while (true) {
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long nextPrintTime = System.currentTimeMillis() + PRINT_DELAY;
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long curTime;
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while ((curTime = System.currentTimeMillis()) < nextPrintTime) {
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try {
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Thread.sleep(nextPrintTime - curTime);
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}
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catch (InterruptedException e) {}
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}
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Stream.of(buckets)
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.parallel()
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.map(Buckets::getBuckets)
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.map(values -> "Current values: " + getTotal(values) + " " + Arrays.toString(values))
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.forEach(System.out::println)
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;
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}
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}
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}
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}
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106
Task/Atomic-updates/Java/atomic-updates.java
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106
Task/Atomic-updates/Java/atomic-updates.java
Normal file
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@ -0,0 +1,106 @@
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import java.util.Arrays;
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import java.util.concurrent.ThreadLocalRandom;
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public class AtomicUpdates {
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private static final int NUM_BUCKETS = 10;
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public static class Buckets {
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private final int[] data;
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public Buckets(int[] data) {
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this.data = data.clone();
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}
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public int getBucket(int index) {
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synchronized (data) {
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return data[index];
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}
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}
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public int transfer(int srcIndex, int dstIndex, int amount) {
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if (amount < 0)
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throw new IllegalArgumentException("negative amount: " + amount);
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if (amount == 0)
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return 0;
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synchronized (data) {
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if (data[srcIndex] - amount < 0)
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amount = data[srcIndex];
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if (data[dstIndex] + amount < 0)
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amount = Integer.MAX_VALUE - data[dstIndex];
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if (amount < 0)
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throw new IllegalStateException();
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data[srcIndex] -= amount;
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data[dstIndex] += amount;
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return amount;
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}
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}
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public int[] getBuckets() {
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synchronized (data) {
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return data.clone();
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}
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}
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}
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private static long getTotal(int[] values) {
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long total = 0;
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for (int value : values) {
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total += value;
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}
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return total;
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}
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public static void main(String[] args) {
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ThreadLocalRandom rnd = ThreadLocalRandom.current();
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int[] values = new int[NUM_BUCKETS];
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for (int i = 0; i < values.length; i++)
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values[i] = rnd.nextInt() & Integer.MAX_VALUE;
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System.out.println("Initial Array: " + getTotal(values) + " " + Arrays.toString(values));
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Buckets buckets = new Buckets(values);
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new Thread(() -> equalize(buckets), "equalizer").start();
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new Thread(() -> transferRandomAmount(buckets), "transferrer").start();
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new Thread(() -> print(buckets), "printer").start();
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}
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private static void transferRandomAmount(Buckets buckets) {
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ThreadLocalRandom rnd = ThreadLocalRandom.current();
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while (true) {
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int srcIndex = rnd.nextInt(NUM_BUCKETS);
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int dstIndex = rnd.nextInt(NUM_BUCKETS);
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int amount = rnd.nextInt() & Integer.MAX_VALUE;
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buckets.transfer(srcIndex, dstIndex, amount);
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}
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}
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private static void equalize(Buckets buckets) {
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ThreadLocalRandom rnd = ThreadLocalRandom.current();
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while (true) {
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int srcIndex = rnd.nextInt(NUM_BUCKETS);
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int dstIndex = rnd.nextInt(NUM_BUCKETS);
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int amount = (buckets.getBucket(srcIndex) - buckets.getBucket(dstIndex)) / 2;
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if (amount >= 0)
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buckets.transfer(srcIndex, dstIndex, amount);
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}
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}
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private static void print(Buckets buckets) {
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while (true) {
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long nextPrintTime = System.currentTimeMillis() + 3000;
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long now;
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while ((now = System.currentTimeMillis()) < nextPrintTime) {
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try {
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Thread.sleep(nextPrintTime - now);
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} catch (InterruptedException e) {
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return;
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}
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}
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int[] bucketValues = buckets.getBuckets();
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System.out.println("Current values: " + getTotal(bucketValues) + " " + Arrays.toString(bucketValues));
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}
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}
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}
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