Resolves #102 and Code Optimizations
This commit is contained in:
Keshavram Kuduwa
GitHub
parent
c4879d4104
commit
a53549ae50
@ -18,62 +18,124 @@ package dev.morling.onebrc;
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import java.io.IOException;
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import java.nio.file.Files;
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import java.nio.file.Path;
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import java.util.DoubleSummaryStatistics;
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import java.util.Map;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.function.Function;
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import java.util.function.ToDoubleFunction;
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import java.util.stream.Collectors;
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import java.util.stream.Stream;
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public class CalculateAverage_kuduwa_keshavram {
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private static final String FILE = "./measurements.txt";
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private record Measurement(double min, double max, double sum, long count) {
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Measurement(double initialMeasurement) {
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this(initialMeasurement, initialMeasurement, initialMeasurement, 1);
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}
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public static Measurement combineWith(Measurement m1, Measurement m2) {
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return new Measurement(
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m1.min < m2.min ? m1.min : m2.min,
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m1.max > m2.max ? m1.max : m2.max,
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m1.sum + m2.sum,
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m1.count + m2.count);
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}
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public String toString() {
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return round(min) + "/" + round(sum / count) + "/" + round(max);
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}
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private double round(double value) {
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return Math.round(value * 10.0) / 10.0;
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}
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}
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public static void main(String[] args) throws IOException {
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// long before = System.currentTimeMillis();
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Map<String, Measurement> resultMap = new ConcurrentHashMap<>();
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Files.lines(Path.of(FILE))
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.parallel()
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.forEach(
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line -> {
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private static final Function<String, String> KEY_MAPPER = line -> {
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int pivot = line.indexOf(";");
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String key = line.substring(0, pivot);
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Measurement measured = new Measurement(Double.parseDouble(line.substring(pivot + 1)));
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Measurement existingMeasurement = resultMap.get(key);
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if (existingMeasurement != null) {
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resultMap.put(key, Measurement.combineWith(existingMeasurement, measured));
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return line.substring(0, pivot);
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};
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private static final ToDoubleFunction<String> VALUE_MAPPER = line -> {
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int pivot = line.indexOf(";");
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return toDouble(line.substring(pivot + 1));
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};
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public static void main(String[] args) throws IOException, InterruptedException {
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try (Stream<String> lines = Files.lines(Path.of(FILE))) {
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Map<String, DoubleSummaryStatistics> resultMap = lines
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.parallel()
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.collect(
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Collectors.groupingBy(KEY_MAPPER, Collectors.summarizingDouble(VALUE_MAPPER)));
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System.out.println(
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resultMap.entrySet().stream()
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.sorted(Map.Entry.comparingByKey())
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.map(
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entry -> String.format(
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"%s=%.1f/%.1f/%.1f",
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entry.getKey(),
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entry.getValue().getMin(),
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entry.getValue().getAverage(),
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entry.getValue().getMax()))
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.collect(Collectors.joining(", ", "{", "}")));
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}
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}
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private static final long MAX_VALUE_DIVIDE_10 = Long.MAX_VALUE / 10;
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private static double toDouble(String num) {
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long value = 0;
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int exp = 0;
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boolean negative = false;
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int decimalPlaces = Integer.MIN_VALUE;
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for (byte ch : num.getBytes()) {
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if (ch >= '0' && ch <= '9') {
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value = value * 10 + (ch - '0');
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decimalPlaces++;
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}
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else if (ch == '-') {
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negative = true;
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}
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else if (ch == '.') {
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decimalPlaces = 0;
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}
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else {
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resultMap.put(key, measured);
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}
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});
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System.out.print("{");
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System.out.print(
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resultMap.entrySet().stream()
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.map(Object::toString)
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.sorted()
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.collect(Collectors.joining(", ")));
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System.out.println("}");
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// System.out.println("Took: " + (System.currentTimeMillis() - before));
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break;
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}
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}
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return asDouble(value, exp, negative, decimalPlaces);
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}
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private static double asDouble(long value, int exp, boolean negative, int decimalPlaces) {
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if (decimalPlaces > 0 && value < Long.MAX_VALUE / 2) {
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if (value < Long.MAX_VALUE / (1L << 32)) {
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exp -= 32;
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value <<= 32;
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}
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if (value < Long.MAX_VALUE / (1L << 16)) {
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exp -= 16;
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value <<= 16;
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}
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if (value < Long.MAX_VALUE / (1L << 8)) {
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exp -= 8;
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value <<= 8;
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}
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if (value < Long.MAX_VALUE / (1L << 4)) {
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exp -= 4;
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value <<= 4;
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}
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if (value < Long.MAX_VALUE / (1L << 2)) {
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exp -= 2;
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value <<= 2;
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}
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if (value < Long.MAX_VALUE / (1L << 1)) {
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exp -= 1;
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value <<= 1;
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}
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}
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for (; decimalPlaces > 0; decimalPlaces--) {
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exp--;
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long mod = value % 5;
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value /= 5;
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int modDiv = 1;
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if (value < Long.MAX_VALUE / (1L << 4)) {
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exp -= 4;
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value <<= 4;
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modDiv <<= 4;
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}
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if (value < Long.MAX_VALUE / (1L << 2)) {
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exp -= 2;
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value <<= 2;
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modDiv <<= 2;
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}
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if (value < Long.MAX_VALUE / (1L << 1)) {
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exp -= 1;
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value <<= 1;
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modDiv <<= 1;
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}
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if (decimalPlaces > 1)
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value += modDiv * mod / 5;
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else
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value += (modDiv * mod + 4) / 5;
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}
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final double d = Math.scalb((double) value, exp);
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return negative ? -d : d;
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}
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}
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