624 lines
30 KiB
Java
624 lines
30 KiB
Java
/*
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* Copyright 2023 The original authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package dev.morling.onebrc;
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import java.io.BufferedWriter;
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import java.io.File;
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import java.io.FileWriter;
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import java.io.IOException;
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import java.util.Arrays;
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import java.util.List;
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import java.util.concurrent.ThreadLocalRandom;
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import org.rschwietzke.CheaperCharBuffer;
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import org.rschwietzke.FastRandom;
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/**
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* Faster version with some data faking instead of a real Gaussian distribution
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* Good enough for our purppose I guess.
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*/
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public class CreateMeasurements2 {
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private static final String FILE = "./measurements2.txt";
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static class WeatherStation {
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final static char[] NUMBERS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
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final String id;
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final int meanTemperature;
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final char[] firstPart;
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final FastRandom r = new FastRandom(ThreadLocalRandom.current().nextLong());
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WeatherStation(String id, double meanTemperature) {
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this.id = id;
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this.meanTemperature = (int) meanTemperature;
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// make it directly copyable
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this.firstPart = (id + ";").toCharArray();
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}
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/**
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* We write out data into the buffer to avoid string conversion
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* We also no longer use double and gaussian, because for our
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* purpose, the fake numbers here will do it. Less
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*
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* @param buffer the buffer to append to
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*/
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void measurement(final CheaperCharBuffer buffer) {
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// fake -10.9 to +10.9 variance without double operations and rounding
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// gives us -10 to +10
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int m = meanTemperature + (r.nextInt(21) - 10);
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// gives us a decimal digit 0 to 9 as char
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char d = NUMBERS[r.nextInt(10)];
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// just append, only one number has to be converted and we can do
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// better... if we watn
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buffer.append(firstPart, 0, firstPart.length)
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.append(String.valueOf(m)).append('.').append(d)
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.append('\n');
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}
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}
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public static void main(String[] args) throws Exception {
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long start = System.currentTimeMillis();
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if (args.length != 1) {
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System.out.println("Usage: create_measurements.sh <number of records to create>");
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System.exit(1);
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}
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int size = 0;
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try {
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size = Integer.parseInt(args[0]);
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}
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catch (NumberFormatException e) {
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System.out.println("Invalid value for <number of records to create>");
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System.out.println("Usage: CreateMeasurements <number of records to create>");
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System.exit(1);
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}
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// @formatter:off
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// data from https://en.wikipedia.org/wiki/List_of_cities_by_average_temperature;
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// converted using https://wikitable2csv.ggor.de/
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// brought to form using DuckDB:
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// D copy (
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// select City, regexp_extract(Year,'(.*)\n.*', 1) as AverageTemp
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// from (
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// select City,Year
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// from read_csv_auto('List_of_cities_by_average_temperature_1.csv', header = true)
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// union
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// select City,Year
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// from read_csv_auto('List_of_cities_by_average_temperature_2.csv', header = true)
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// union
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// select City,Year
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// from read_csv_auto('List_of_cities_by_average_temperature_3.csv', header = true)
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// union
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// select City,Year
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// from read_csv_auto('List_of_cities_by_average_temperature_4.csv', header = true)
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// union
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// select City,Year
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// from read_csv_auto('List_of_cities_by_average_temperature_5.csv', header = true)
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// )
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// ) TO 'output.csv' (HEADER, DELIMITER ',');
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// @formatter:on
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final List<WeatherStation> stations = Arrays.asList(
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new WeatherStation("Abha", 18.0),
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new WeatherStation("Abidjan", 26.0),
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new WeatherStation("Abéché", 29.4),
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new WeatherStation("Accra", 26.4),
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new WeatherStation("Addis Ababa", 16.0),
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new WeatherStation("Adelaide", 17.3),
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new WeatherStation("Aden", 29.1),
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new WeatherStation("Ahvaz", 25.4),
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new WeatherStation("Albuquerque", 14.0),
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new WeatherStation("Alexandra", 11.0),
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new WeatherStation("Alexandria", 20.0),
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new WeatherStation("Algiers", 18.2),
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new WeatherStation("Alice Springs", 21.0),
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new WeatherStation("Almaty", 10.0),
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new WeatherStation("Amsterdam", 10.2),
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new WeatherStation("Anadyr", -6.9),
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new WeatherStation("Anchorage", 2.8),
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new WeatherStation("Andorra la Vella", 9.8),
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new WeatherStation("Ankara", 12.0),
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new WeatherStation("Antananarivo", 17.9),
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new WeatherStation("Antsiranana", 25.2),
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new WeatherStation("Arkhangelsk", 1.3),
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new WeatherStation("Ashgabat", 17.1),
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new WeatherStation("Asmara", 15.6),
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new WeatherStation("Assab", 30.5),
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new WeatherStation("Astana", 3.5),
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new WeatherStation("Athens", 19.2),
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new WeatherStation("Atlanta", 17.0),
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new WeatherStation("Auckland", 15.2),
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new WeatherStation("Austin", 20.7),
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new WeatherStation("Baghdad", 22.77),
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new WeatherStation("Baguio", 19.5),
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new WeatherStation("Baku", 15.1),
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new WeatherStation("Baltimore", 13.1),
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new WeatherStation("Bamako", 27.8),
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new WeatherStation("Bangkok", 28.6),
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new WeatherStation("Bangui", 26.0),
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new WeatherStation("Banjul", 26.0),
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new WeatherStation("Barcelona", 18.2),
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new WeatherStation("Bata", 25.1),
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new WeatherStation("Batumi", 14.0),
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new WeatherStation("Beijing", 12.9),
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new WeatherStation("Beirut", 20.9),
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new WeatherStation("Belgrade", 12.5),
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new WeatherStation("Belize City", 26.7),
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new WeatherStation("Benghazi", 19.9),
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new WeatherStation("Bergen", 7.7),
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new WeatherStation("Berlin", 10.3),
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new WeatherStation("Bilbao", 14.7),
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new WeatherStation("Birao", 26.5),
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new WeatherStation("Bishkek", 11.3),
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new WeatherStation("Bissau", 27.0),
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new WeatherStation("Blantyre", 22.2),
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new WeatherStation("Bloemfontein", 15.6),
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new WeatherStation("Boise", 11.4),
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new WeatherStation("Bordeaux", 14.2),
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new WeatherStation("Bosaso", 30.0),
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new WeatherStation("Boston", 10.9),
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new WeatherStation("Bouaké", 26.0),
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new WeatherStation("Bratislava", 10.5),
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new WeatherStation("Brazzaville", 25.0),
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new WeatherStation("Bridgetown", 27.0),
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new WeatherStation("Brisbane", 21.4),
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new WeatherStation("Brussels", 10.5),
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new WeatherStation("Bucharest", 10.8),
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new WeatherStation("Budapest", 11.3),
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new WeatherStation("Bujumbura", 23.8),
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new WeatherStation("Bulawayo", 18.9),
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new WeatherStation("Burnie", 13.1),
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new WeatherStation("Busan", 15.0),
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new WeatherStation("Cabo San Lucas", 23.9),
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new WeatherStation("Cairns", 25.0),
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new WeatherStation("Cairo", 21.4),
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new WeatherStation("Calgary", 4.4),
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new WeatherStation("Canberra", 13.1),
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new WeatherStation("Cape Town", 16.2),
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new WeatherStation("Changsha", 17.4),
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new WeatherStation("Charlotte", 16.1),
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new WeatherStation("Chiang Mai", 25.8),
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new WeatherStation("Chicago", 9.8),
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new WeatherStation("Chihuahua", 18.6),
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new WeatherStation("Chișinău", 10.2),
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new WeatherStation("Chittagong", 25.9),
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new WeatherStation("Chongqing", 18.6),
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new WeatherStation("Christchurch", 12.2),
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new WeatherStation("City of San Marino", 11.8),
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new WeatherStation("Colombo", 27.4),
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new WeatherStation("Columbus", 11.7),
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new WeatherStation("Conakry", 26.4),
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new WeatherStation("Copenhagen", 9.1),
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new WeatherStation("Cotonou", 27.2),
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new WeatherStation("Cracow", 9.3),
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new WeatherStation("Da Lat", 17.9),
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new WeatherStation("Da Nang", 25.8),
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new WeatherStation("Dakar", 24.0),
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new WeatherStation("Dallas", 19.0),
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new WeatherStation("Damascus", 17.0),
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new WeatherStation("Dampier", 26.4),
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new WeatherStation("Dar es Salaam", 25.8),
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new WeatherStation("Darwin", 27.6),
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new WeatherStation("Denpasar", 23.7),
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new WeatherStation("Denver", 10.4),
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new WeatherStation("Detroit", 10.0),
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new WeatherStation("Dhaka", 25.9),
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new WeatherStation("Dikson", -11.1),
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new WeatherStation("Dili", 26.6),
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new WeatherStation("Djibouti", 29.9),
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new WeatherStation("Dodoma", 22.7),
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new WeatherStation("Dolisie", 24.0),
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new WeatherStation("Douala", 26.7),
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new WeatherStation("Dubai", 26.9),
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new WeatherStation("Dublin", 9.8),
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new WeatherStation("Dunedin", 11.1),
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new WeatherStation("Durban", 20.6),
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new WeatherStation("Dushanbe", 14.7),
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new WeatherStation("Edinburgh", 9.3),
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new WeatherStation("Edmonton", 4.2),
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new WeatherStation("El Paso", 18.1),
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new WeatherStation("Entebbe", 21.0),
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new WeatherStation("Erbil", 19.5),
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new WeatherStation("Erzurum", 5.1),
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new WeatherStation("Fairbanks", -2.3),
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new WeatherStation("Fianarantsoa", 17.9),
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new WeatherStation("Flores, Petén", 26.4),
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new WeatherStation("Frankfurt", 10.6),
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new WeatherStation("Fresno", 17.9),
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new WeatherStation("Fukuoka", 17.0),
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new WeatherStation("Gabès", 19.5),
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new WeatherStation("Gaborone", 21.0),
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new WeatherStation("Gagnoa", 26.0),
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new WeatherStation("Gangtok", 15.2),
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new WeatherStation("Garissa", 29.3),
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new WeatherStation("Garoua", 28.3),
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new WeatherStation("George Town", 27.9),
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new WeatherStation("Ghanzi", 21.4),
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new WeatherStation("Gjoa Haven", -14.4),
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new WeatherStation("Guadalajara", 20.9),
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new WeatherStation("Guangzhou", 22.4),
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new WeatherStation("Guatemala City", 20.4),
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new WeatherStation("Halifax", 7.5),
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new WeatherStation("Hamburg", 9.7),
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new WeatherStation("Hamilton", 13.8),
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new WeatherStation("Hanga Roa", 20.5),
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new WeatherStation("Hanoi", 23.6),
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new WeatherStation("Harare", 18.4),
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new WeatherStation("Harbin", 5.0),
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new WeatherStation("Hargeisa", 21.7),
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new WeatherStation("Hat Yai", 27.0),
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new WeatherStation("Havana", 25.2),
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new WeatherStation("Helsinki", 5.9),
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new WeatherStation("Heraklion", 18.9),
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new WeatherStation("Hiroshima", 16.3),
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new WeatherStation("Ho Chi Minh City", 27.4),
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new WeatherStation("Hobart", 12.7),
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new WeatherStation("Hong Kong", 23.3),
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new WeatherStation("Honiara", 26.5),
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new WeatherStation("Honolulu", 25.4),
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new WeatherStation("Houston", 20.8),
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new WeatherStation("Ifrane", 11.4),
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new WeatherStation("Indianapolis", 11.8),
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new WeatherStation("Iqaluit", -9.3),
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new WeatherStation("Irkutsk", 1.0),
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new WeatherStation("Istanbul", 13.9),
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new WeatherStation("İzmir", 17.9),
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new WeatherStation("Jacksonville", 20.3),
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new WeatherStation("Jakarta", 26.7),
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new WeatherStation("Jayapura", 27.0),
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new WeatherStation("Jerusalem", 18.3),
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new WeatherStation("Johannesburg", 15.5),
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new WeatherStation("Jos", 22.8),
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new WeatherStation("Juba", 27.8),
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new WeatherStation("Kabul", 12.1),
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new WeatherStation("Kampala", 20.0),
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new WeatherStation("Kandi", 27.7),
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new WeatherStation("Kankan", 26.5),
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new WeatherStation("Kano", 26.4),
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new WeatherStation("Kansas City", 12.5),
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new WeatherStation("Karachi", 26.0),
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new WeatherStation("Karonga", 24.4),
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new WeatherStation("Kathmandu", 18.3),
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new WeatherStation("Khartoum", 29.9),
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new WeatherStation("Kingston", 27.4),
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new WeatherStation("Kinshasa", 25.3),
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new WeatherStation("Kolkata", 26.7),
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new WeatherStation("Kuala Lumpur", 27.3),
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new WeatherStation("Kumasi", 26.0),
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new WeatherStation("Kunming", 15.7),
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new WeatherStation("Kuopio", 3.4),
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new WeatherStation("Kuwait City", 25.7),
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new WeatherStation("Kyiv", 8.4),
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new WeatherStation("Kyoto", 15.8),
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new WeatherStation("La Ceiba", 26.2),
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new WeatherStation("La Paz", 23.7),
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new WeatherStation("Lagos", 26.8),
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new WeatherStation("Lahore", 24.3),
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new WeatherStation("Lake Havasu City", 23.7),
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new WeatherStation("Lake Tekapo", 8.7),
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new WeatherStation("Las Palmas de Gran Canaria", 21.2),
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new WeatherStation("Las Vegas", 20.3),
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new WeatherStation("Launceston", 13.1),
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new WeatherStation("Lhasa", 7.6),
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new WeatherStation("Libreville", 25.9),
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new WeatherStation("Lisbon", 17.5),
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new WeatherStation("Livingstone", 21.8),
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new WeatherStation("Ljubljana", 10.9),
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new WeatherStation("Lodwar", 29.3),
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new WeatherStation("Lomé", 26.9),
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new WeatherStation("London", 11.3),
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new WeatherStation("Los Angeles", 18.6),
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new WeatherStation("Louisville", 13.9),
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new WeatherStation("Luanda", 25.8),
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new WeatherStation("Lubumbashi", 20.8),
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new WeatherStation("Lusaka", 19.9),
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new WeatherStation("Luxembourg City", 9.3),
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new WeatherStation("Lviv", 7.8),
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new WeatherStation("Lyon", 12.5),
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new WeatherStation("Madrid", 15.0),
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new WeatherStation("Mahajanga", 26.3),
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new WeatherStation("Makassar", 26.7),
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new WeatherStation("Makurdi", 26.0),
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new WeatherStation("Malabo", 26.3),
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new WeatherStation("Malé", 28.0),
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new WeatherStation("Managua", 27.3),
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new WeatherStation("Manama", 26.5),
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new WeatherStation("Mandalay", 28.0),
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new WeatherStation("Mango", 28.1),
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new WeatherStation("Manila", 28.4),
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new WeatherStation("Maputo", 22.8),
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new WeatherStation("Marrakesh", 19.6),
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new WeatherStation("Marseille", 15.8),
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new WeatherStation("Maun", 22.4),
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new WeatherStation("Medan", 26.5),
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new WeatherStation("Mek'ele", 22.7),
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new WeatherStation("Melbourne", 15.1),
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new WeatherStation("Memphis", 17.2),
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new WeatherStation("Mexicali", 23.1),
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new WeatherStation("Mexico City", 17.5),
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new WeatherStation("Miami", 24.9),
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new WeatherStation("Milan", 13.0),
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new WeatherStation("Milwaukee", 8.9),
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new WeatherStation("Minneapolis", 7.8),
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new WeatherStation("Minsk", 6.7),
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new WeatherStation("Mogadishu", 27.1),
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new WeatherStation("Mombasa", 26.3),
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new WeatherStation("Monaco", 16.4),
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new WeatherStation("Moncton", 6.1),
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new WeatherStation("Monterrey", 22.3),
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new WeatherStation("Montreal", 6.8),
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new WeatherStation("Moscow", 5.8),
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new WeatherStation("Mumbai", 27.1),
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new WeatherStation("Murmansk", 0.6),
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new WeatherStation("Muscat", 28.0),
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new WeatherStation("Mzuzu", 17.7),
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new WeatherStation("N'Djamena", 28.3),
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new WeatherStation("Naha", 23.1),
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new WeatherStation("Nairobi", 17.8),
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new WeatherStation("Nakhon Ratchasima", 27.3),
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new WeatherStation("Napier", 14.6),
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new WeatherStation("Napoli", 15.9),
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new WeatherStation("Nashville", 15.4),
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new WeatherStation("Nassau", 24.6),
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new WeatherStation("Ndola", 20.3),
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new WeatherStation("New Delhi", 25.0),
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new WeatherStation("New Orleans", 20.7),
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new WeatherStation("New York City", 12.9),
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new WeatherStation("Ngaoundéré", 22.0),
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new WeatherStation("Niamey", 29.3),
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new WeatherStation("Nicosia", 19.7),
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new WeatherStation("Niigata", 13.9),
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new WeatherStation("Nouadhibou", 21.3),
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new WeatherStation("Nouakchott", 25.7),
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new WeatherStation("Novosibirsk", 1.7),
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new WeatherStation("Nuuk", -1.4),
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new WeatherStation("Odesa", 10.7),
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new WeatherStation("Odienné", 26.0),
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new WeatherStation("Oklahoma City", 15.9),
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new WeatherStation("Omaha", 10.6),
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new WeatherStation("Oranjestad", 28.1),
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new WeatherStation("Oslo", 5.7),
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new WeatherStation("Ottawa", 6.6),
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new WeatherStation("Ouagadougou", 28.3),
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new WeatherStation("Ouahigouya", 28.6),
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new WeatherStation("Ouarzazate", 18.9),
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new WeatherStation("Oulu", 2.7),
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new WeatherStation("Palembang", 27.3),
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new WeatherStation("Palermo", 18.5),
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new WeatherStation("Palm Springs", 24.5),
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new WeatherStation("Palmerston North", 13.2),
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new WeatherStation("Panama City", 28.0),
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new WeatherStation("Parakou", 26.8),
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new WeatherStation("Paris", 12.3),
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new WeatherStation("Perth", 18.7),
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new WeatherStation("Petropavlovsk-Kamchatsky", 1.9),
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new WeatherStation("Philadelphia", 13.2),
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new WeatherStation("Phnom Penh", 28.3),
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new WeatherStation("Phoenix", 23.9),
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new WeatherStation("Pittsburgh", 10.8),
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new WeatherStation("Podgorica", 15.3),
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new WeatherStation("Pointe-Noire", 26.1),
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new WeatherStation("Pontianak", 27.7),
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new WeatherStation("Port Moresby", 26.9),
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new WeatherStation("Port Sudan", 28.4),
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new WeatherStation("Port Vila", 24.3),
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new WeatherStation("Port-Gentil", 26.0),
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new WeatherStation("Portland (OR)", 12.4),
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new WeatherStation("Porto", 15.7),
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new WeatherStation("Prague", 8.4),
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new WeatherStation("Praia", 24.4),
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new WeatherStation("Pretoria", 18.2),
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new WeatherStation("Pyongyang", 10.8),
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new WeatherStation("Rabat", 17.2),
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new WeatherStation("Rangpur", 24.4),
|
|
new WeatherStation("Reggane", 28.3),
|
|
new WeatherStation("Reykjavík", 4.3),
|
|
new WeatherStation("Riga", 6.2),
|
|
new WeatherStation("Riyadh", 26.0),
|
|
new WeatherStation("Rome", 15.2),
|
|
new WeatherStation("Roseau", 26.2),
|
|
new WeatherStation("Rostov-on-Don", 9.9),
|
|
new WeatherStation("Sacramento", 16.3),
|
|
new WeatherStation("Saint Petersburg", 5.8),
|
|
new WeatherStation("Saint-Pierre", 5.7),
|
|
new WeatherStation("Salt Lake City", 11.6),
|
|
new WeatherStation("San Antonio", 20.8),
|
|
new WeatherStation("San Diego", 17.8),
|
|
new WeatherStation("San Francisco", 14.6),
|
|
new WeatherStation("San Jose", 16.4),
|
|
new WeatherStation("San José", 22.6),
|
|
new WeatherStation("San Juan", 27.2),
|
|
new WeatherStation("San Salvador", 23.1),
|
|
new WeatherStation("Sana'a", 20.0),
|
|
new WeatherStation("Santo Domingo", 25.9),
|
|
new WeatherStation("Sapporo", 8.9),
|
|
new WeatherStation("Sarajevo", 10.1),
|
|
new WeatherStation("Saskatoon", 3.3),
|
|
new WeatherStation("Seattle", 11.3),
|
|
new WeatherStation("Ségou", 28.0),
|
|
new WeatherStation("Seoul", 12.5),
|
|
new WeatherStation("Seville", 19.2),
|
|
new WeatherStation("Shanghai", 16.7),
|
|
new WeatherStation("Singapore", 27.0),
|
|
new WeatherStation("Skopje", 12.4),
|
|
new WeatherStation("Sochi", 14.2),
|
|
new WeatherStation("Sofia", 10.6),
|
|
new WeatherStation("Sokoto", 28.0),
|
|
new WeatherStation("Split", 16.1),
|
|
new WeatherStation("St. John's", 5.0),
|
|
new WeatherStation("St. Louis", 13.9),
|
|
new WeatherStation("Stockholm", 6.6),
|
|
new WeatherStation("Surabaya", 27.1),
|
|
new WeatherStation("Suva", 25.6),
|
|
new WeatherStation("Suwałki", 7.2),
|
|
new WeatherStation("Sydney", 17.7),
|
|
new WeatherStation("Tabora", 23.0),
|
|
new WeatherStation("Tabriz", 12.6),
|
|
new WeatherStation("Taipei", 23.0),
|
|
new WeatherStation("Tallinn", 6.4),
|
|
new WeatherStation("Tamale", 27.9),
|
|
new WeatherStation("Tamanrasset", 21.7),
|
|
new WeatherStation("Tampa", 22.9),
|
|
new WeatherStation("Tashkent", 14.8),
|
|
new WeatherStation("Tauranga", 14.8),
|
|
new WeatherStation("Tbilisi", 12.9),
|
|
new WeatherStation("Tegucigalpa", 21.7),
|
|
new WeatherStation("Tehran", 17.0),
|
|
new WeatherStation("Tel Aviv", 20.0),
|
|
new WeatherStation("Thessaloniki", 16.0),
|
|
new WeatherStation("Thiès", 24.0),
|
|
new WeatherStation("Tijuana", 17.8),
|
|
new WeatherStation("Timbuktu", 28.0),
|
|
new WeatherStation("Tirana", 15.2),
|
|
new WeatherStation("Toamasina", 23.4),
|
|
new WeatherStation("Tokyo", 15.4),
|
|
new WeatherStation("Toliara", 24.1),
|
|
new WeatherStation("Toluca", 12.4),
|
|
new WeatherStation("Toronto", 9.4),
|
|
new WeatherStation("Tripoli", 20.0),
|
|
new WeatherStation("Tromsø", 2.9),
|
|
new WeatherStation("Tucson", 20.9),
|
|
new WeatherStation("Tunis", 18.4),
|
|
new WeatherStation("Ulaanbaatar", -0.4),
|
|
new WeatherStation("Upington", 20.4),
|
|
new WeatherStation("Ürümqi", 7.4),
|
|
new WeatherStation("Vaduz", 10.1),
|
|
new WeatherStation("Valencia", 18.3),
|
|
new WeatherStation("Valletta", 18.8),
|
|
new WeatherStation("Vancouver", 10.4),
|
|
new WeatherStation("Veracruz", 25.4),
|
|
new WeatherStation("Vienna", 10.4),
|
|
new WeatherStation("Vientiane", 25.9),
|
|
new WeatherStation("Villahermosa", 27.1),
|
|
new WeatherStation("Vilnius", 6.0),
|
|
new WeatherStation("Virginia Beach", 15.8),
|
|
new WeatherStation("Vladivostok", 4.9),
|
|
new WeatherStation("Warsaw", 8.5),
|
|
new WeatherStation("Washington, D.C.", 14.6),
|
|
new WeatherStation("Wau", 27.8),
|
|
new WeatherStation("Wellington", 12.9),
|
|
new WeatherStation("Whitehorse", -0.1),
|
|
new WeatherStation("Wichita", 13.9),
|
|
new WeatherStation("Willemstad", 28.0),
|
|
new WeatherStation("Winnipeg", 3.0),
|
|
new WeatherStation("Wrocław", 9.6),
|
|
new WeatherStation("Xi'an", 14.1),
|
|
new WeatherStation("Yakutsk", -8.8),
|
|
new WeatherStation("Yangon", 27.5),
|
|
new WeatherStation("Yaoundé", 23.8),
|
|
new WeatherStation("Yellowknife", -4.3),
|
|
new WeatherStation("Yerevan", 12.4),
|
|
new WeatherStation("Yinchuan", 9.0),
|
|
new WeatherStation("Zagreb", 10.7),
|
|
new WeatherStation("Zanzibar City", 26.0),
|
|
new WeatherStation("Zürich", 9.3));
|
|
|
|
File file = new File(FILE);
|
|
|
|
// break the loop and unroll it manually
|
|
int strideSize = 50_000_000;
|
|
int outer = size / strideSize;
|
|
int remainder = size - (outer * strideSize);
|
|
|
|
try (final BufferedWriter bw = new BufferedWriter(new FileWriter(file))) {
|
|
for (int i = 0; i < outer; i++) {
|
|
produce(bw, stations, strideSize);
|
|
|
|
// we avoid a modulo if here and use the stride size to print and update
|
|
System.out.println("Wrote %,d measurements in %s ms".formatted((i + 1) * strideSize, System.currentTimeMillis() - start));
|
|
}
|
|
// there might be a rest
|
|
produce(bw, stations, remainder);
|
|
|
|
// write fully before taking measurements
|
|
bw.flush();
|
|
System.out.println("Created file with %,d measurements in %s ms".formatted(size, System.currentTimeMillis() - start));
|
|
}
|
|
}
|
|
|
|
private static void produce(BufferedWriter bw, List<WeatherStation> stations, int count) throws IOException {
|
|
final int stationCount = stations.size();
|
|
final int rest = count % 8;
|
|
|
|
// use a fast ranodm impl without atomics to be able to utilize the cpu better
|
|
// and avoid sideeffects, FastRandom is very fake random and does not have a state
|
|
final FastRandom r1 = new FastRandom(ThreadLocalRandom.current().nextLong());
|
|
final FastRandom r2 = new FastRandom(ThreadLocalRandom.current().nextLong());
|
|
final FastRandom r3 = new FastRandom(ThreadLocalRandom.current().nextLong());
|
|
final FastRandom r4 = new FastRandom(ThreadLocalRandom.current().nextLong());
|
|
|
|
// write to a fix buffer first, don't create strings ever
|
|
// reuse buffer
|
|
final CheaperCharBuffer sb = new CheaperCharBuffer(200);
|
|
|
|
// manual loop unroll for less jumps
|
|
for (int i = 0; i < count; i = i + 8) {
|
|
{
|
|
// try to fill teh cpu pipeline as much as possible with
|
|
// independent operations
|
|
int s1 = r1.nextInt(stationCount);
|
|
int s2 = r2.nextInt(stationCount);
|
|
int s3 = r3.nextInt(stationCount);
|
|
int s4 = r4.nextInt(stationCount);
|
|
// get us the ojects one after the other to have the array
|
|
// in our L1 cache and not push it out with other data
|
|
var w1 = stations.get(s1);
|
|
var w2 = stations.get(s2);
|
|
var w3 = stations.get(s3);
|
|
var w4 = stations.get(s4);
|
|
// write our data to our buffer
|
|
w1.measurement(sb);
|
|
w2.measurement(sb);
|
|
w3.measurement(sb);
|
|
w4.measurement(sb);
|
|
}
|
|
{
|
|
int s1 = r1.nextInt(stationCount);
|
|
int s2 = r2.nextInt(stationCount);
|
|
int s3 = r3.nextInt(stationCount);
|
|
int s4 = r4.nextInt(stationCount);
|
|
var w1 = stations.get(s1);
|
|
var w2 = stations.get(s2);
|
|
var w3 = stations.get(s3);
|
|
var w4 = stations.get(s4);
|
|
w1.measurement(sb);
|
|
w2.measurement(sb);
|
|
w3.measurement(sb);
|
|
w4.measurement(sb);
|
|
}
|
|
// write the buffer directly, no intermediate string copy
|
|
bw.write(sb.data_, 0, sb.length_);
|
|
|
|
// reuse buffer, reset only, no cleaning
|
|
sb.clear();
|
|
}
|
|
|
|
// there might be a rest to write
|
|
for (int i = 0; i < rest; i++) {
|
|
sb.clear();
|
|
|
|
int s = r1.nextInt(stationCount);
|
|
var w = stations.get(s);
|
|
w.measurement(sb);
|
|
|
|
bw.write(sb.data_, 0, sb.length_);
|
|
}
|
|
}
|
|
}
|