org.apfloat.samples.Pi Maven / Gradle / Ivy
/*
* MIT License
*
* Copyright (c) 2002-2021 Mikko Tommila
*
* 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.apfloat.samples;
import java.io.Serializable;
import java.io.PrintWriter;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicLong;
import org.apfloat.Apfloat;
import org.apfloat.ApfloatContext;
import org.apfloat.ApfloatMath;
import org.apfloat.ApfloatRuntimeException;
/**
* Calculates pi using four different algorithms.
*
* @version 1.8.2
* @author Mikko Tommila
*/
public class Pi
{
// Implementation note: we use printf() for printing, because it flushes the output (print() does not)
/**
* Terms for the binary splitting series.
*/
protected static interface BinarySplittingSeries
extends Serializable
{
/**
* Binary splitting term.
*
* @param n The term.
*
* @return The value.
*/
public Apfloat a(long n)
throws ApfloatRuntimeException;
/**
* Binary splitting term.
*
* @param n The term.
*
* @return The value.
*/
public Apfloat p(long n)
throws ApfloatRuntimeException;
/**
* Binary splitting term.
*
* @param n The term.
*
* @return The value.
*/
public Apfloat q(long n)
throws ApfloatRuntimeException;
}
/**
* Abstract base class for the binary splitting series.
*/
protected static abstract class AbstractBinarySplittingSeries
implements BinarySplittingSeries
{
/**
* Construct a binary splitting series with the specified precision and radix.
*
* @param precision The target precision.
* @param radix The radix to be used.
*/
protected AbstractBinarySplittingSeries(long precision, int radix)
{
this.precision = precision;
this.radix = radix;
}
/**
* Target precision.
*/
protected long precision;
/**
* Radix to be used.
*/
protected int radix;
private static final long serialVersionUID = 1L;
}
/**
* Chudnovskys' algorithm terms for the binary splitting series.
*/
protected static class ChudnovskyBinarySplittingSeries
extends AbstractBinarySplittingSeries
{
/**
* Basic constructor.
*
* @param precision The precision.
* @param radix The radix.
*/
public ChudnovskyBinarySplittingSeries(long precision, int radix)
{
super(precision, radix);
this.A = new Apfloat(13591409, precision, radix);
this.B = new Apfloat(545140134, precision, radix);
this.J = new Apfloat(10939058860032000L, precision, radix);
this.ONE = new Apfloat(1, precision, radix);
this.TWO = new Apfloat(2, precision, radix);
this.FIVE = new Apfloat(5, precision, radix);
this.SIX = new Apfloat(6, precision, radix);
}
@Override
public Apfloat a(long n)
throws ApfloatRuntimeException
{
Apfloat s = new Apfloat(n, Apfloat.INFINITE, this.radix),
v = this.A.add(this.B.multiply(s));
v = ((n & 1) == 0 ? v : v.negate());
return v;
}
@Override
public Apfloat p(long n)
throws ApfloatRuntimeException
{
Apfloat v;
if (n == 0)
{
v = this.ONE;
}
else
{
Apfloat f = new Apfloat(n, Apfloat.INFINITE, this.radix),
sixf = this.SIX.multiply(f);
v = sixf.subtract(this.ONE).multiply(this.TWO.multiply(f).subtract(this.ONE)).multiply(sixf.subtract(this.FIVE));
}
return v;
}
@Override
public Apfloat q(long n)
throws ApfloatRuntimeException
{
Apfloat v;
if (n == 0)
{
v = this.ONE;
}
else
{
Apfloat f = new Apfloat(n, Apfloat.INFINITE, this.radix);
v = this.J.multiply(f.multiply(f).multiply(f));
}
return v;
}
private static final long serialVersionUID = 1L;
private final Apfloat A;
private final Apfloat B;
private final Apfloat J;
private final Apfloat ONE;
private final Apfloat TWO;
private final Apfloat FIVE;
private final Apfloat SIX;
}
/**
* Ramanujan's algorithm terms for the binary splitting series.
*/
protected static class RamanujanBinarySplittingSeries
extends AbstractBinarySplittingSeries
{
/**
* Basic constructor.
*
* @param precision The precision.
* @param radix The radix.
*/
public RamanujanBinarySplittingSeries(long precision, int radix)
{
super(precision, radix);
this.A = new Apfloat(1103, precision, radix);
this.B = new Apfloat(26390, precision, radix);
this.J = new Apfloat(3073907232L, precision, radix);
this.ONE = new Apfloat(1, precision, radix);
this.TWO = new Apfloat(2, precision, radix);
this.THREE = new Apfloat(3, precision, radix);
this.FOUR = new Apfloat(4, precision, radix);
}
@Override
public Apfloat a(long n)
throws ApfloatRuntimeException
{
Apfloat s = new Apfloat(n, Apfloat.INFINITE, this.radix),
v = this.A.add(this.B.multiply(s));
return v;
}
@Override
public Apfloat p(long n)
throws ApfloatRuntimeException
{
Apfloat v;
if (n == 0)
{
v = this.ONE;
}
else
{
Apfloat f = new Apfloat(n, Apfloat.INFINITE, this.radix),
fourf = this.FOUR.multiply(f);
v = fourf.subtract(this.ONE).multiply(this.TWO.multiply(f).subtract(this.ONE)).multiply(fourf.subtract(this.THREE));
}
return v;
}
@Override
public Apfloat q(long n)
throws ApfloatRuntimeException
{
Apfloat v;
if (n == 0)
{
v = this.ONE;
}
else
{
Apfloat f = new Apfloat(n, Apfloat.INFINITE, this.radix);
v = this.J.multiply(f.multiply(f).multiply(f));
}
return v;
}
private static final long serialVersionUID = 1L;
private final Apfloat A;
private final Apfloat B;
private final Apfloat J;
private final Apfloat ONE;
private final Apfloat TWO;
private final Apfloat THREE;
private final Apfloat FOUR;
}
/**
* Class for implementing the binary splitting algorithm.
*/
protected static class BinarySplittingPiCalculator
implements Serializable
{
/**
* Construct a pi calculator with the specified precision and radix.
*
* @param series The binary splitting series to be used.
*/
public BinarySplittingPiCalculator(BinarySplittingSeries series)
{
this.series = series;
}
/**
* Entry point for the binary splitting algorithm.
*
* @param n1 Start term.
* @param n2 End term.
* @param T Algorithm parameter.
* @param Q Algorithm parameter.
* @param P Algorithm parameter.
* @param progressIndicator Class to print out the progress of the calculation.
*/
public void r(long n1, long n2, ApfloatHolder T, ApfloatHolder Q, ApfloatHolder P, BinarySplittingProgressIndicator progressIndicator)
throws ApfloatRuntimeException
{
checkAlive();
assert (n1 != n2);
long length = n2 - n1;
if (length == 1)
{
Apfloat p0 = p(n1);
T.setApfloat(a(n1).multiply(p0));
Q.setApfloat(q(n1));
if (P != null) P.setApfloat(p0);
}
else
{
long nMiddle = n1 + n2 >> 1;
ApfloatHolder LT = new ApfloatHolder(),
LQ = new ApfloatHolder(),
LP = new ApfloatHolder();
r(n1, nMiddle, LT, LQ, LP, progressIndicator);
r(nMiddle, n2, T, Q, P, progressIndicator);
T.setApfloat(Q.getApfloat().multiply(LT.getApfloat()).add(LP.getApfloat().multiply(T.getApfloat())));
Q.setApfloat(LQ.getApfloat().multiply(Q.getApfloat()));
if (P != null) P.setApfloat(LP.getApfloat().multiply(P.getApfloat()));
}
if (progressIndicator != null)
{
progressIndicator.progress(n1, n2);
}
}
private Apfloat a(long n)
throws ApfloatRuntimeException
{
return this.series.a(n);
}
private Apfloat p(long n)
throws ApfloatRuntimeException
{
return this.series.p(n);
}
private Apfloat q(long n)
throws ApfloatRuntimeException
{
return this.series.q(n);
}
private static final long serialVersionUID = 1L;
private BinarySplittingSeries series;
}
/**
* Basic class for calculating pi using the Chudnovskys' binary splitting algorithm.
*/
public static class ChudnovskyPiCalculator
implements Operation
{
/**
* Construct a pi calculator with the specified precision and radix.
*
* @param precision The target precision.
* @param radix The radix to be used.
*/
public ChudnovskyPiCalculator(long precision, int radix)
throws ApfloatRuntimeException
{
this(new BinarySplittingPiCalculator(new ChudnovskyBinarySplittingSeries(precision, radix)), precision, radix);
}
/**
* Construct a pi calculator with the specified binary splitting algorithm.
*
* @param calculator The binary splitting algorithm to be used.
* @param precision The target precision.
* @param radix The radix to be used.
*/
protected ChudnovskyPiCalculator(BinarySplittingPiCalculator calculator, long precision, int radix)
throws ApfloatRuntimeException
{
this.calculator = calculator;
this.precision = precision;
this.radix = radix;
}
/**
* Calculate pi using the Chudnovskys' binary splitting algorithm.
*/
@Override
public Apfloat execute()
{
Pi.err.println("Using the Chudnovsky brothers' binary splitting algorithm");
ApfloatHolder T = new ApfloatHolder(),
Q = new ApfloatHolder();
// Perform the calculation of T, Q and P to requested precision only, to improve performance
long terms = (long) ((double) this.precision * Math.log((double) this.radix) / 32.654450041768516);
long time = System.currentTimeMillis();
this.calculator.r(0, terms + 1, T, Q, null, new BinarySplittingProgressIndicator(terms));
time = System.currentTimeMillis() - time;
Pi.err.println("100% complete, elapsed time " + time / 1000.0 + " seconds");
Pi.err.printf("Final value ");
time = System.currentTimeMillis();
Apfloat t = T.getApfloat(),
q = Q.getApfloat();
checkAlive();
Apfloat factor = ApfloatMath.inverseRoot(new Apfloat(1823176476672000L, this.precision, this.radix), 2);
checkAlive();
Apfloat pi = ApfloatMath.inverseRoot(factor.multiply(t), 1).multiply(q);
time = System.currentTimeMillis() - time;
Pi.err.println("took " + time / 1000.0 + " seconds");
return pi;
}
private static final long serialVersionUID = 1L;
private BinarySplittingPiCalculator calculator;
private long precision;
private int radix;
}
/**
* Basic class for calculating pi using the Ramanujan binary splitting algorithm.
*/
public static class RamanujanPiCalculator
implements Operation
{
/**
* Construct a pi calculator with the specified precision and radix.
*
* @param precision The target precision.
* @param radix The radix to be used.
*/
public RamanujanPiCalculator(long precision, int radix)
throws ApfloatRuntimeException
{
this(new BinarySplittingPiCalculator(new RamanujanBinarySplittingSeries(precision, radix)), precision, radix);
}
/**
* Construct a pi calculator with the specified binary splitting algorithm.
*
* @param calculator The binary splitting algorithm to be used.
* @param precision The target precision.
* @param radix The radix to be used.
*/
protected RamanujanPiCalculator(BinarySplittingPiCalculator calculator, long precision, int radix)
throws ApfloatRuntimeException
{
this.calculator = calculator;
this.precision = precision;
this.radix = radix;
}
/**
* Calculate pi using the Ramanujan binary splitting algorithm.
*/
@Override
public Apfloat execute()
{
Pi.err.println("Using the Ramanujan binary splitting algorithm");
ApfloatHolder T = new ApfloatHolder(),
Q = new ApfloatHolder();
// Perform the calculation of T, Q and P to requested precision only, to improve performance
long terms = (long) ((double) this.precision * Math.log((double) this.radix) / 18.38047940053836);
long time = System.currentTimeMillis();
this.calculator.r(0, terms + 1, T, Q, null, new BinarySplittingProgressIndicator(terms));
time = System.currentTimeMillis() - time;
Pi.err.println("100% complete, elapsed time " + time / 1000.0 + " seconds");
Pi.err.printf("Final value ");
time = System.currentTimeMillis();
Apfloat t = T.getApfloat(),
q = Q.getApfloat();
checkAlive();
Apfloat factor = ApfloatMath.inverseRoot(new Apfloat(8, this.precision, this.radix), 2);
checkAlive();
Apfloat pi = ApfloatMath.inverseRoot(t, 1).multiply(factor).multiply(new Apfloat(9801, Apfloat.INFINITE, this.radix)).multiply(q);
time = System.currentTimeMillis() - time;
Pi.err.println("took " + time / 1000.0 + " seconds");
return pi;
}
private static final long serialVersionUID = 1L;
private BinarySplittingPiCalculator calculator;
private long precision;
private int radix;
}
/**
* Indicates progress of the pi calculation using
* the binary splitting algorithm.
*
* This implementation is thread safe for multiple
* threads to use concurrently.
*/
public static class BinarySplittingProgressIndicator
implements Serializable
{
/**
* Construct a progress indicator with the specified
* number of terms of the series.
*
* @param terms Total number of terms to be calculated.
*/
public BinarySplittingProgressIndicator(long terms)
{
this.totalElements = (long) (terms * (Math.log((double) terms) / Math.log(2.0) + 1.0)) + 1;
this.currentElements = new AtomicLong(); // Use atomic long for thread safe but non-blocking access
}
/**
* Advances the progress.
*
* @param n1 First term that has been calculated.
* @param n2 Last term that has been calculated, minus one.
*/
public void progress(long n1, long n2)
{
long length = n2 - n1;
// For small ranges the amount of progress is advanced in one chunk, including the progress of all the recursive steps
long addedElements;
if (length < PROGRESS_RECURSION_THRESHOLD >> 1)
{
// Sub-range of a small range, was progressed already
return;
}
else if (length < PROGRESS_RECURSION_THRESHOLD)
{
// Small range, calculate the recursive progress
addedElements = recursiveLength(length);
}
else
{
// Large range, calculate just this step
addedElements = length;
}
long oldElements = this.currentElements.getAndAdd(addedElements);
long elements = oldElements + addedElements;
int oldPercentComplete = (int) (100 * oldElements / this.totalElements);
int percentComplete = (int) (100 * elements / this.totalElements);
if (percentComplete != oldPercentComplete)
{
Pi.err.printf(percentComplete + "%% complete\r");
}
}
private long recursiveLength(long length)
{
long recursiveLength;
if (length == 1)
{
recursiveLength = 1;
}
else if (length == PROGRESS_RECURSION_THRESHOLD - 1)
{
// Borderline case, half of this will be calculated separately
recursiveLength = recursiveLength(length >> 1) + length;
}
else
{
long halfLength = length >> 1;
recursiveLength = recursiveLength(halfLength) + recursiveLength(length - halfLength) + length;
}
return recursiveLength;
}
private static final long serialVersionUID = 1L;
private static final long PROGRESS_RECURSION_THRESHOLD = 32;
private long totalElements;
private AtomicLong currentElements;
}
/**
* Calculates pi using the Gauss-Legendre algorithm.
*/
public static class GaussLegendrePiCalculator
implements Operation
{
/**
* Construct a pi calculator with the specified precision and radix.
*
* @param precision The target precision.
* @param radix The radix to be used.
*/
public GaussLegendrePiCalculator(long precision, int radix)
{
this.precision = precision;
this.radix = radix;
}
/**
* Calculate pi using the Gauss-Legendre iteration.
*/
@Override
public Apfloat execute()
{
Pi.err.println("Using the Gauss-Legendre iteration");
int iterations = 0;
while (gaussLegendrePrecision(iterations, 4, this.radix) < this.precision)
{
iterations++;
}
Pi.err.println("Total " + iterations + " iterations");
Pi.err.printf("Initial values ");
long time = System.currentTimeMillis();
Apfloat two = new Apfloat(2, this.precision, this.radix),
four = new Apfloat(4, this.precision, this.radix),
a = new Apfloat(1, this.precision, this.radix),
b = ApfloatMath.inverseRoot(two, 2),
t = a.divide(four);
time = System.currentTimeMillis() - time;
Pi.err.println("took " + time / 1000.0 + " seconds");
for (int i = 0; i < iterations; i++)
{
checkAlive();
Pi.err.printf("Iteration " + (i + 1) + " ");
time = System.currentTimeMillis();
Apfloat tmp = a;
a = a.add(b).divide(two);
checkAlive();
b = tmp.multiply(b);
checkAlive();
b = ApfloatMath.sqrt(b);
checkAlive();
t = t.subtract(new Apfloat(1L << i, this.precision, this.radix).multiply(ApfloatMath.pow(tmp.subtract(a), 2)));
time = System.currentTimeMillis() - time;
Pi.err.println("took " + time / 1000.0 + " seconds");
}
checkAlive();
Pi.err.printf("Final value ");
time = System.currentTimeMillis();
a = a.add(b);
t = four.multiply(t);
Apfloat pi = ApfloatMath.pow(a, 2).divide(t);
time = System.currentTimeMillis() - time;
Pi.err.println("took " + time / 1000.0 + " seconds");
return pi;
}
// What precision is achieved with k Gauss-Legendre iterations
private static long gaussLegendrePrecision(int k, int r, int radix)
{
return (long) ((Math.pow(2.0, (double) k) * Math.sqrt((double) r) * Math.PI - Math.log(16.0 * Math.sqrt((double) r)) - k * Math.log(2.0)) / Math.log((double) radix));
}
private static final long serialVersionUID = 1L;
private long precision;
private int radix;
}
/**
* Calculates pi using the Borweins' quartic algorithm.
*/
public static class BorweinPiCalculator
implements Operation
{
/**
* Construct a pi calculator with the specified precision and radix.
*
* @param precision The target precision.
* @param radix The radix to be used.
*/
public BorweinPiCalculator(long precision, int radix)
{
this.precision = precision;
this.radix = radix;
}
/**
* Calculate pi using the Borweins' quartic iteration.
*/
@Override
public Apfloat execute()
{
Pi.err.println("Using the Borweins' quartic iteration");
int iterations = 0;
while (borweinPrecision(iterations, 4, this.radix) < this.precision)
{
iterations++;
}
Pi.err.println("Total " + iterations + " iterations");
Pi.err.printf("Initial values ");
long time = System.currentTimeMillis();
Apfloat one = new Apfloat(1, this.precision, this.radix),
two = new Apfloat(2, this.precision, this.radix),
four = new Apfloat(4, this.precision, this.radix),
y = ApfloatMath.sqrt(two).subtract(one),
a = two.subtract(four.multiply(y));
time = System.currentTimeMillis() - time;
Pi.err.println("took " + time / 1000.0 + " seconds");
for (int i = 0; i < iterations; i++)
{
checkAlive();
Pi.err.printf("Iteration " + (i + 1) + " ");
time = System.currentTimeMillis();
Apfloat tmp = ApfloatMath.pow(y, 4);
y = one.subtract(tmp);
checkAlive();
y = ApfloatMath.inverseRoot(y, 4);
checkAlive();
y = y.subtract(one).divide(y.add(one));
checkAlive();
tmp = ApfloatMath.pow(y.add(one), 2);
checkAlive();
a = a.multiply(tmp).multiply(tmp);
checkAlive();
a = a.subtract(new Apfloat(1L << (2 * i + 3), this.precision, this.radix).multiply(y).multiply(tmp.subtract(y)));
time = System.currentTimeMillis() - time;
Pi.err.println("took " + time / 1000.0 + " seconds");
}
checkAlive();
Pi.err.printf("Final value ");
time = System.currentTimeMillis();
Apfloat pi = one.divide(a);
time = System.currentTimeMillis() - time;
Pi.err.println("took " + time / 1000.0 + " seconds");
return pi;
}
// What precision is achieved with k Borweins' quartic iterations
private static long borweinPrecision(int k, int r, int radix)
{
return (long) ((Math.pow(4.0, (double) k) * Math.sqrt((double) r) * Math.PI - Math.log(16.0 * Math.sqrt((double) r)) - k * Math.log(4.0)) / Math.log((double) radix));
}
private static final long serialVersionUID = 1L;
private long precision;
private int radix;
}
/**
* Parse a long from an argument.
*
* @param arg The string to be parsed.
* @param name Description of the argument.
* @param minValue Minimum allowed value.
* @param maxValue Maximum allowed value.
*
* @return Valid long.
*/
protected static long getLong(String arg, String name, long minValue, long maxValue)
{
long value = 0;
try
{
value = Long.parseLong(arg);
if (value < minValue || value > maxValue)
{
throw new NumberFormatException();
}
}
catch (NumberFormatException nfe)
{
System.err.println("Invalid " + name + ": " + arg);
System.exit(1);
}
return value;
}
/**
* Parse an integer from an argument.
*
* @param arg The string to be parsed.
* @param name Description of the argument.
* @param minValue Minimum allowed value.
* @param maxValue Maximum allowed value.
*
* @return Valid integer.
*/
protected static int getInt(String arg, String name, int minValue, int maxValue)
{
return (int) getLong(arg, name, minValue, maxValue);
}
/**
* Parse the precision from an argument.
*
* @param arg The string to be parsed.
*
* @return Valid precision.
*/
protected static long getPrecision(String arg)
{
return getLong(arg, "digits", 1, Apfloat.INFINITE - 1);
}
/**
* Parse the radix from an argument.
*
* @param arg The string to be parsed.
*
* @return Valid radix.
*/
protected static int getRadix(String arg)
{
return getInt(arg, "radix", Character.MIN_RADIX, Character.MAX_RADIX);
}
private static void dump()
{
ApfloatContext ctx = ApfloatContext.getContext();
Pi.err.println("builderFactory = " + ctx.getBuilderFactory().getClass().getName());
Pi.err.println("maxMemoryBlockSize = " + ctx.getMaxMemoryBlockSize());
Pi.err.println("cacheL1Size = " + ctx.getCacheL1Size());
Pi.err.println("cacheL2Size = " + ctx.getCacheL2Size());
Pi.err.println("cacheBurst = " + ctx.getCacheBurst());
Pi.err.println("memoryThreshold = " + ctx.getMemoryThreshold());
Pi.err.println("sharedMemoryTreshold = " + ctx.getSharedMemoryTreshold());
Pi.err.println("blockSize = " + ctx.getBlockSize());
Pi.err.println("numberOfProcessors = " + ctx.getNumberOfProcessors());
}
/**
* Execute an operation and display some additional information.
* The return value of the operation is written to {@link #out}.
*
* @param precision The precision to be used.
* @param radix The radix to be used.
* @param operation The operation to execute.
*
* @exception IOException In case writing the output fails.
*/
public static void run(long precision, int radix, Operation operation)
throws IOException, ApfloatRuntimeException
{
dump();
Pi.err.println("Calculating pi to " + precision + " radix-" + radix + " digits");
long time = System.currentTimeMillis();
Apfloat pi = operation.execute();
time = System.currentTimeMillis() - time;
pi.writeTo(Pi.out, true);
Pi.out.println();
Pi.err.println("Total elapsed time " + time / 1000.0 + " seconds");
}
/**
* Set the output stream for the result printout.
*
* @param out The output stream.
*/
public static void setOut(PrintWriter out)
{
Pi.out = out;
}
/**
* Get the output stream for the result printout.
*
* @return The output stream.
*/
public static PrintWriter getOut()
{
return Pi.out;
}
/**
* Set the output stream for status messages printout.
*
* @param err The output stream.
*/
public static void setErr(PrintWriter err)
{
Pi.err = err;
}
/**
* Get the output stream for status messages printout.
*
* @return The output stream.
*/
public static PrintWriter getErr()
{
return Pi.err;
}
/**
* Set whether the program should stop executing.
*
* @param isAlive true to keep running the program, false to stop.
*/
public static void setAlive(boolean isAlive)
{
Pi.isAlive = isAlive;
}
Pi()
{
}
/**
* Command-line entry point.
*
* @param args Command-line parameters.
*
* @exception IOException In case writing the output fails.
*/
public static void main(String[] args)
throws IOException, ApfloatRuntimeException
{
if (args.length < 1)
{
System.err.println("USAGE: Pi digits [method] [radix]");
System.err.println(" method: 0 = Chudnovskys' binsplit");
System.err.println(" 1 = Ramanujan binsplit");
System.err.println(" 2 = Gauss-Legendre");
System.err.println(" 3 = Borweins' quartic");
System.err.println(" radix must be 2...36");
return;
}
long precision = getPrecision(args[0]);
int method = (args.length > 1 ? getInt(args[1], "method", 0, 3) : 0),
radix = (args.length > 2 ? getRadix(args[2]) : ApfloatContext.getContext().getDefaultRadix());
Operation operation;
switch (method)
{
case 0:
operation = new ChudnovskyPiCalculator(precision, radix);
break;
case 1:
operation = new RamanujanPiCalculator(precision, radix);
break;
case 2:
operation = new GaussLegendrePiCalculator(precision, radix);
break;
default:
operation = new BorweinPiCalculator(precision, radix);
}
setOut(new PrintWriter(System.out, true));
setErr(new PrintWriter(System.err, true));
run(precision, radix, operation);
}
/**
* Check whether the program should stop executing.
*
* @exception ThreadDeath in case {@link #setAlive(boolean)} has been set to false.
*/
protected static void checkAlive()
{
if (!Pi.isAlive)
{
throw new ThreadDeath();
}
}
/**
* Output stream for the result printout.
*/
protected static PrintWriter out;
/**
* Output stream for status messages printout.
*/
protected static PrintWriter err;
// Interactive execution stop check
private static volatile boolean isAlive = true;
}