On 8/13/13 7:20 AM, er...@apache.org wrote: > Author: erans > Date: Tue Aug 13 14:20:26 2013 > New Revision: 1513501 > > URL: http://svn.apache.org/r1513501 > Log: > MATH-1019 > Removed dead link in Javadoc; added entry to original reference > in "LICENCE" file. > > Modified: > commons/proper/math/trunk/LICENSE.txt > > commons/proper/math/trunk/src/main/java/org/apache/commons/math3/random/RandomDataGenerator.java > > commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java > > Modified: commons/proper/math/trunk/LICENSE.txt > URL: > http://svn.apache.org/viewvc/commons/proper/math/trunk/LICENSE.txt?rev=1513501&r1=1513500&r2=1513501&view=diff > ============================================================================== > --- commons/proper/math/trunk/LICENSE.txt (original) > +++ commons/proper/math/trunk/LICENSE.txt Tue Aug 13 14:20:26 2013 > @@ -385,3 +385,16 @@ Th Orekit library is described at: > https://www.orekit.org/forge/projects/orekit > The original files are distributed under the terms of the Apache 2 license > which is: Copyright 2010 CS Communication & Systèmes > + > +=============================================================================== > + > +The initial code for shuffling an array (originally in class > +"org.apache.commons.math3.random.RandomDataGenerator", now replaced by > +a method in class "org.apache.commons.math3.util.MathArrays") was > +inspired from the algorithm description provided in > +"Algorithms", by Ian Craw and John Pulham (University of Aberdeen 1999). > +The textbook (containing a proof that the shuffle is uniformly random) is > +available here: > + > http://citeseerx.ist.psu.edu/viewdoc/download;?doi=10.1.1.173.1898&rep=rep1&type=pdf > + > +===============================================================================
No need to add to LICENSE and probably wrong to do so here. There was no code consulted or used in the reference. Just the algorithm. We should not fill up LICENSE with references to sources for *algorithms* - only previously licensed code used directly or used as a basis for implementation. Best to drop from here and (optionally) add the reference to the javadoc. The value of adding it there is that it provides background and justification for the algorithm, much as other algorithm references elsewhere in the codebase do. Phil > > Modified: > commons/proper/math/trunk/src/main/java/org/apache/commons/math3/random/RandomDataGenerator.java > URL: > http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/random/RandomDataGenerator.java?rev=1513501&r1=1513500&r2=1513501&view=diff > ============================================================================== > --- > commons/proper/math/trunk/src/main/java/org/apache/commons/math3/random/RandomDataGenerator.java > (original) > +++ > commons/proper/math/trunk/src/main/java/org/apache/commons/math3/random/RandomDataGenerator.java > Tue Aug 13 14:20:26 2013 > @@ -620,11 +620,10 @@ public class RandomDataGenerator impleme > /** > * {@inheritDoc} > * > - * <p> > - * Uses a 2-cycle permutation shuffle. The shuffling process is > described <a > - * href="http://www.maths.abdn.ac.uk/~igc/tch/mx4002/notes/node83.html";> > - * here</a>. > - * </p> > + * This method calls {@link MathArrays#shuffle(int[],RandomGenerator) > + * MathArrays.shuffle} in order to create a random shuffle of the set > + * of natural numbers {@code { 0, 1, ..., n - 1 }}. > + * > * @throws NumberIsTooLargeException if {@code k > n}. > * @throws NotStrictlyPositiveException if {@code k <= 0}. > */ > @@ -649,15 +648,8 @@ public class RandomDataGenerator impleme > /** > * {@inheritDoc} > * > - * <p> > - * <strong>Algorithm Description</strong>: Uses a 2-cycle permutation > - * shuffle to generate a random permutation of <code>c.size()</code> and > - * then returns the elements whose indexes correspond to the elements of > the > - * generated permutation. This technique is described, and proven to > - * generate random samples <a > - * href="http://www.maths.abdn.ac.uk/~igc/tch/mx4002/notes/node83.html";> > - * here</a> > - * </p> > + * This method calls {@link #nextPermutation(int,int) > nextPermutation(c.size(), k)} > + * in order to sample the collection. > */ > public Object[] nextSample(Collection<?> c, int k) throws > NumberIsTooLargeException, NotStrictlyPositiveException { > > > Modified: > commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java > URL: > http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java?rev=1513501&r1=1513500&r2=1513501&view=diff > ============================================================================== > --- > commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java > (original) > +++ > commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java > Tue Aug 13 14:20:26 2013 > @@ -1442,6 +1442,8 @@ public class MathArrays { > * The {@code start} and {@code pos} parameters select which portion > * of the array is randomized and which is left untouched. > * > + * @see #shuffle(int[],int,Position,RandomGenerator) > + * > * @param list Array whose entries will be shuffled (in-place). > * @param start Index at which shuffling begins. > * @param pos Shuffling is performed for index positions between > @@ -1455,7 +1457,9 @@ public class MathArrays { > } > > /** > - * Shuffle the entries of the given array. > + * Shuffle the entries of the given array, using the > + * <a > href="http://en.wikipedia.org/wiki/FisherâYates_shuffle#The_modern_algorithm";> > + * FisherâYates</a> algorithm. > * The {@code start} and {@code pos} parameters select which portion > * of the array is randomized and which is left untouched. > * > @@ -1509,6 +1513,8 @@ public class MathArrays { > /** > * Shuffle the entries of the given array. > * > + * @see #shuffle(int[],int,Position,RandomGenerator) > + * > * @param list Array whose entries will be shuffled (in-place). > * @param rng Random number generator. > */ > @@ -1520,6 +1526,8 @@ public class MathArrays { > /** > * Shuffle the entries of the given array. > * > + * @see #shuffle(int[],int,Position,RandomGenerator) > + * > * @param list Array whose entries will be shuffled (in-place). > */ > public static void shuffle(int[] list) { > > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
