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Gilles 2016-05-23 17:46:57 +02:00
parent 34eba81322
commit c82bb1b56a
1 changed files with 15 additions and 14 deletions
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29
src/main/java/org/apache/commons/math4/rng/RandomSource.java
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@ -31,7 +31,7 @@ import org.apache.commons.math4.rng.internal.source64.TwoCmres;
* </code></pre>
* or
* <pre><code>
* final int[] seed = new int[] { 196, 9, 0, 226 };
* final int[] seed = new int[] { 196, 9, 0, 226 };
* UniformRandomProvider rng = RandomSource.create(RandomSource.MT, seed);
* </code></pre>
* or
@ -44,8 +44,8 @@ import org.apache.commons.math4.rng.internal.source64.TwoCmres;
* (optional) seed.
* <br>
* In the first form, a random seed will be {@link SeedFactory generated
* automatically}; the random seed generation step is explicit in the
* third form.
* automatically}; in the second form, a fixed seed is used; a random seed
* is explicitly generated in the third form.
* </p>
*
* <p>
@ -68,22 +68,22 @@ import org.apache.commons.math4.rng.internal.source64.TwoCmres;
* internal state.
* <br>
* When the seed value passed by the caller is of the native type, it is
* expected that the sequences produced will be the same as those
* produced by other implementations of the algorithm.
* expected that the sequences produced will be identical to those
* produced by other implementations of the same reference algorithm.
* <br>
* However, when the seed value passed by the caller is not of the native
* type, a transformation is performed by this library and the resulting
* native type value will <i>not</i> contain more information than the
* original seed value.
* If the algorithm's native type is "simpler" than the type passed by
* the caller, then some (unuse) information will even be lost.
* the caller, then some (unused) information will even be lost.
* <br>
* The transformation from non-native to native seed type is arbitrary,
* as long as it does not reduce the amount of information required by
* the algorithm to initialize its state.
* The consequence of the transformation is that the sequences produced
* by this library may not be the same as the sequences produced by other
* implementations of the same algorithm!
* The consequence of the transformation is that sequences produced
* by this library may <i>not</i> be the same as the sequences produced
* by other implementations of the same algorithm!
* </p>
*
* <p>
@ -93,11 +93,12 @@ import org.apache.commons.math4.rng.internal.source64.TwoCmres;
* generators factory method}.
* <br>
* Although the seed-generating methods defined in this class will likely
* return different values for all calls, there is no guarantee that the
* produced seed will result always in a "good" sequence of numbers, even
* if the generator is good.
* return different values each time they are called, there is no guarantee
* that the resulting "seed" will always generate a <i>good</i> (i.e.
* sufficiently uniformly random for the intended purpose) sequence of
* numbers, even if the generator is good!
* The only way to ensure that the selected seed will make the generator
* produce a "good" sequence is to submit that sequence to a series of
* produce a good sequence is to submit that sequence to a series of
* stringent tests, as provided by tools such as
* <a href="http://www.phy.duke.edu/~rgb/General/dieharder.php">dieharder</a>
* or <a href="http://simul.iro.umontreal.ca/testu01/tu01.html">TestU01</a>.
@ -133,7 +134,7 @@ import org.apache.commons.math4.rng.internal.source64.TwoCmres;
* used for {@link #restoreState(UniformRandomProvider,State) restoring}
* a generator (of the same type) to an identical state (e.g. to allow
* persistent storage, or to continue a sequence from where the original
* instance left off.).
* instance left off).
* </p>
*
* @since 4.0