1brc/src/main/java/dev/morling/onebrc/CalculateAverage_kumarsaurav123.java
2024-01-11 10:48:03 +01:00

257 lines
11 KiB
Java

/*
* Copyright 2023 The original authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package dev.morling.onebrc;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.StandardCharsets;
import java.nio.file.Paths;
import java.util.*;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collector;
import java.util.stream.IntStream;
import static java.util.stream.Collectors.groupingBy;
public class CalculateAverage_kumarsaurav123 {
private static final String FILE = "./measurements.txt";
private static record Measurement(String station, double value) {
private Measurement(String[] parts) {
this(parts[0], Double.parseDouble(parts[1]));
}
}
private static record ResultRow(String station,double min, double mean, double max,double sum,double count) {
public String toString() {
return round(min) + "/" + round(mean) + "/" + round(max);
}
private double round(double value) {
return Math.round(value * 10.0) / 10.0;
}
}
;
private static class MeasurementAggregator {
private double min = Double.POSITIVE_INFINITY;
private double max = Double.NEGATIVE_INFINITY;
private double sum;
private long count;
private String station;
}
public static void main(String[] args) {
HashMap<Byte, Integer> map = new HashMap<>();
map.put((byte) 48, 0);
map.put((byte) 49, 1);
map.put((byte) 50, 2);
map.put((byte) 51, 3);
map.put((byte) 52, 4);
map.put((byte) 53, 5);
map.put((byte) 54, 6);
map.put((byte) 55, 7);
map.put((byte) 56, 8);
map.put((byte) 57, 9);
Collector<ResultRow, MeasurementAggregator, ResultRow> collector2 = Collector.of(
MeasurementAggregator::new,
(a, m) -> {
a.min = Math.min(a.min, m.min);
a.max = Math.max(a.max, m.max);
a.sum += m.sum;
a.count += m.count;
},
(agg1, agg2) -> {
var res = new MeasurementAggregator();
res.min = Math.min(agg1.min, agg2.min);
res.max = Math.max(agg1.max, agg2.max);
res.sum = agg1.sum + agg2.sum;
res.count = agg1.count + agg2.count;
return res;
},
agg -> {
return new ResultRow(agg.station, agg.min, agg.sum / agg.count, agg.max, agg.sum, agg.count);
});
Collector<Measurement, MeasurementAggregator, ResultRow> collector = Collector.of(
MeasurementAggregator::new,
(a, m) -> {
a.min = Math.min(a.min, m.value);
a.max = Math.max(a.max, m.value);
a.sum += m.value;
a.station = m.station;
a.count++;
},
(agg1, agg2) -> {
var res = new MeasurementAggregator();
res.min = Math.min(agg1.min, agg2.min);
res.max = Math.max(agg1.max, agg2.max);
res.sum = agg1.sum + agg2.sum;
res.count = agg1.count + agg2.count;
return res;
},
agg -> {
return new ResultRow(agg.station, agg.min, agg.sum / agg.count, agg.max, agg.sum, agg.count);
});
long start = System.currentTimeMillis();
long len = Paths.get(FILE).toFile().length();
Map<Integer, List<byte[]>> leftOutsMap = new ConcurrentSkipListMap<>();
int chunkSize = 1_0000_00;
long proc = Math.max(1, (len / chunkSize));
ExecutorService executor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors() * 2 * 2 * 2);
List<ResultRow> measurements = Collections.synchronizedList(new ArrayList<ResultRow>());
IntStream.range(0, (int) proc)
.mapToObj(i -> {
return new Runnable() {
@Override
public void run() {
try {
RandomAccessFile file = new RandomAccessFile(FILE, "r");
byte[] allBytes2 = new byte[chunkSize];
file.seek((long) i * (long) chunkSize);
int l = file.read(allBytes2);
byte[] eol = "\n".getBytes(StandardCharsets.UTF_8);
byte[] sep = ";".getBytes(StandardCharsets.UTF_8);
List<Measurement> mst = new ArrayList<>();
int st = 0;
int cnt = 0;
ArrayList<byte[]> local = new ArrayList<>();
for (int i = 0; i < l; i++) {
if (allBytes2[i] == eol[0]) {
if (i != 0) {
byte[] s2 = new byte[i - st];
System.arraycopy(allBytes2, st, s2, 0, s2.length);
if (cnt != 0) {
for (int j = 0; j < s2.length; j++) {
if (s2[j] == sep[0]) {
byte[] city = new byte[j];
byte[] value = new byte[s2.length - j - 1];
System.arraycopy(s2, 0, city, 0, city.length);
System.arraycopy(s2, city.length + 1, value, 0, value.length);
double d = 0.0;
int s = -1;
for (int k = value.length - 1; k >= 0; k--) {
if (value[k] == 45) {
d = d * -1;
}
else if (value[k] == 46) {
}
else {
d = d + map.get(value[k]).intValue() * Math.pow(10, s);
s++;
}
}
mst.add(new Measurement(new String(city), d));
}
}
}
else {
local.add(s2);
}
}
cnt++;
st = i + 1;
}
}
if (st < l) {
byte[] s2 = new byte[allBytes2.length - st];
System.arraycopy(allBytes2, st, s2, 0, s2.length);
local.add(s2);
}
leftOutsMap.put(i, local);
allBytes2 = null;
measurements.addAll(mst.stream()
.collect(groupingBy(Measurement::station, collector))
.values());
// System.out.println(measurements.size());
}
catch (Exception e) {
// throw new RuntimeException(e);
System.out.println("");
}
}
};
})
.forEach(executor::submit);
executor.shutdown();
try {
executor.awaitTermination(10, TimeUnit.MINUTES);
}
catch (InterruptedException e) {
throw new RuntimeException(e);
}
Collection<Measurement> lMeasure = new ArrayList<>();
List<byte[]> leftOuts = leftOutsMap.values()
.stream()
.flatMap(List::stream)
.toList();
int size = 0;
for (int i = 0; i < leftOuts.size(); i++) {
size = size + leftOuts.get(i).length;
}
byte[] allBytes = new byte[size];
int pos = 0;
for (int i = 0; i < leftOuts.size(); i++) {
System.arraycopy(leftOuts.get(i), 0, allBytes, pos, leftOuts.get(i).length);
pos = pos + leftOuts.get(i).length;
}
List<String> l = Arrays.asList(new String(allBytes).split(";"));
List<Measurement> measurements1 = new ArrayList<>();
String city = l.get(0);
for (int i = 0; i < l.size() - 1; i++) {
int sIndex = l.get(i + 1).indexOf('.') + 2;
String tempp = l.get(i + 1).substring(0, sIndex);
measurements1.add(new Measurement(city, Double.parseDouble(tempp)));
city = l.get(i + 1).substring(sIndex);
}
measurements.addAll(measurements1.stream()
.collect(groupingBy(Measurement::station, collector))
.values());
Map<String, ResultRow> measurements2 = new TreeMap<>(measurements
.stream()
.parallel()
.collect(groupingBy(ResultRow::station, collector2)));
// Read from bytes 1000 to 2000
// Something like this
//
// Map<String, ResultRow> measurements = new TreeMap<>(Files.lines(Paths.get(FILE))
// .map(l -> new Measurement(l.split(";")))
// .collect(groupingBy(m -> m.station(), collector)));
System.out.println(measurements2);
// System.out.println(System.currentTimeMillis() - start);
}
}