Mega Code Archive
Mersenne
<![CDATA[
/*
* @(#)Mersenne.java 1.0 Apr 26, 2008
*
* The MIT License
*
* Copyright (c) 2008 Malachi de AElfweald <malachid@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
//package org.eoti.math.prime;
import java.math.BigInteger;
import java.util.*;
public class Mersenne
{
protected static BigInteger two = BigInteger.valueOf(2);
protected static String[] primes = new String[]{
"2","3","5","7","13","17","19","31","61","89","107","127","521","607", // M1-M14
"1279","2203","2281","3217","4253","4423","9689","9941","11213", "19937", // M15-M23
"21701","23209","44497","86243","110503","132049","216091","756839", // M24-M32
"859433","1257787","1398269","2976221","3021377","6972593","13466917", // M33-M39
// indexes of rest could be wrong
"20996011","24036583","25964951","30402457","32582657","37156667", // M40-M45???
"42643801", "43112609" // M46-M47???
};
protected BigInteger value;
protected int index;
public Mersenne(int index)
{
this.index = index;
value = two.pow(Integer.parseInt(primes[index-1]));
value = value.subtract(BigInteger.ONE);
}
// Per common Mersenne Prime tables, index is 1-based
public int getIndex(){return index;}
public Integer getN(){return Integer.parseInt(primes[index-1]);}
public Integer getBitLength(){return getN();}
public Integer getDigitLength(){return (""+getValue()).length();}
public BigInteger getValue(){return value;}
public static Iterable<Mersenne> iterator()
{
return new Iterable<Mersenne>()
{
public Iterator<Mersenne> iterator()
{
return new MersenneIter();
}
};
}
static class MersenneIter
implements Iterator<Mersenne>
{
protected int currIndex = 0;
MersenneIter(){}
public boolean hasNext()
{
return currIndex <= primes.length;
}
public Mersenne next()
{
return new Mersenne(++currIndex);
}
public void remove()
{
throw new UnsupportedOperationException("Remove not implemented");
}
}
}
]]>