Java Number Sum sumFirstIntegers(final long i)

Description

Compute the sum of the i first integers.

License

Open Source License

Parameter

Parameter	Description
i	maximum summand

Return

Sum

Declaration

public static long sumFirstIntegers(final long i) 

Method Source Code

//package com.java2s;
/*//from  www .  j  av a2s . co  m
 This file is part of ELKI:
 Environment for Developing KDD-Applications Supported by Index-Structures

 Copyright (C) 2013
 Ludwig-Maximilians-Universit?t M?nchen
 Lehr- und Forschungseinheit f?r Datenbanksysteme
 ELKI Development Team

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

public class Main {
    /**
     * Compute the sum of the i first integers.
     * 
     * @param i maximum summand
     * @return Sum
     */
    public static long sumFirstIntegers(final long i) {
        return ((i - 1L) * i) >> 1;
    }
}

Related

1. sumAsDouble(Iterable values)
2. SumDiffErr(float Term1Err, float Term2Err)
3. sumDigits(String number)
4. sumDivisors(int n)
5. sumError(long samples, long count, double m2, double mean)
6. sumFirstN(long n)
7. sumFirstNDivisibleByM(long n, long m)
8. sumFromNtoM(int n, int m)
9. sumHadOverflow(long a, long b, long sum)