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https://issues.apache.org/jira/browse/RNG-57?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16640722#comment-16640722
]
Alex D Herbert commented on RNG-57:
-----------------------------------
Wow that test is hard to get to pass.
I just tried this using a 1024 byte random seed for all tests. The seed is
stored as a string and decoded using Commons Codec:
{code:java}
public class ProvidersList {
/** List of all RNGs implemented in the library. */
private static final List<RestorableUniformRandomProvider[]> LIST =
new ArrayList<RestorableUniformRandomProvider[]>();
/** List of 32-bits based RNGs. */
private static final List<RestorableUniformRandomProvider[]> LIST32 =
new ArrayList<RestorableUniformRandomProvider[]>();
/** List of 64-bits based RNGs. */
private static final List<RestorableUniformRandomProvider[]> LIST64 =
new ArrayList<RestorableUniformRandomProvider[]>();
/**
* Provide a random byte seed encoded as a hex string (length must be even).
*
* <p>1024 bytes = 2048 hex characters. This provides 128 longs and 256
integers.
*/
private static final String HEX_SEED =
"75d1fb070512e503f9635706318f2dabbd6e2120addbd50c8ff8272654f3082c"
+ "edf244845db03415bf661051d9a487c622b6411a6773596f459465c72d59e870"
+ "c6bd90089a6fb7294d3beea8feba7d8307745cbd1233b6f85ff0294f87483d9a"
+ "ea77939ced0eb7e41617b52ac5a0d32d49c456e7b4c2485bd8d8be990f626458"
+ "86c5194aa34eb1f83efc38808ebf1fcd813667f88e7a76191dee40f662968a8c"
+ "71cf6493497ad77e00efbb59bfbf9b7664f8c32b4f5f29064329174bbce4870d"
+ "bb6bfd683415428d1c2c76eacca237df7119ecf1e6eac7cc97f3548bb10255b0"
+ "74a44010fa4811fc622104cea4ca045c674bbaa65f2273879301c4902bdb2f72"
+ "b9e7b1f5414704bb240a6a4d490a39739a557338b1e58cb5e81d8157172482d0"
+ "407795dffa92caacf3db3c848e1f2962bd5e8ddd4691a49779eea65d38d9d584"
+ "9b7ea054677618a9f56893877c34bb5d928308c8be19e07627b646cc743d0ddf"
+ "44757e64c1268eeb5e88a55a718f4fb9ba313b68ab1729efff6989192c95a2d8"
+ "42292766523b8d03e2dc10b1157b45909ecf239e59a4334eafa0b48c39a980dc"
+ "0f4238dcdaf306a57a29758a23f992eb7d13439ad982ec5a83aac630a31e05a3"
+ "0724a7babb5ebbcc00144c90a9a79c976f7cdd516fd94a432e815e3aeffdccb0"
+ "515a409dcfe7f492c0015234706eff83eda607cf76ec9b0f74a6d3050fc1f469"
+ "42475ef814847c5053fffa1e5d732f8954f1d6a678ce88e19ca92f6d5b945ac3"
+ "f872c05f3481659f27f570f3d387e1a75bc17408d454c6b4190d78c6aeac2cc5"
+ "0d8042b373ca4f149e32b81933076c23c2e3e36d7ba29079dd0e605b617c6378"
+ "ee714b66cb0959f4ff127cf1f0ad42919780fc51174c8818a630d32bfca5b03c"
+ "698e63f774dc979a27dddc795d5146ab49baf32b79014bf2e533e82d663da5d8"
+ "42d57fbe1e1a270ccb17c6daf1ea6cad92a4f6b311dee23f5362106d0cda8130"
+ "ae391221e790a610b6bbd9f64bf988783a5fde4b0d3504a417aac0a1a70b8c4a"
+ "6395ae21e41c1efa31a37737b15d4c8c77909306c41028ea9e04d7f0141b2c13"
+ "d6e0d20a0df619b575eeb1c6aebd7f03b56060c4bf4cf1fdcea3f0a9d03d8e61"
+ "54d8d9c92fb5eba0f3f3ddaa82190c766d0c5acdc52b29cf4dfe45731434e443"
+ "8652301bbba00bad464a467abfe46283adfd05bffad627171140fbbbf6d080a0"
+ "9971e17c0771abe6e354eb2e3330449080cf2133ac5b4a4240c357c50b5b144b"
+ "7c8fd76935fbb2741b4def4ea7f2455d794e600a121d16172fc4c951ba152b89"
+ "99232249e456e47ed12270959e2d5ae97a73b6d448a958e9c644e51af7199ce8"
+ "ed6a277f88a599093214e70832fe52ebf99862ce2e59da603a909075c238a8cf"
+
"42f359f7d269716bf53fcd10e04f3149b55dafce78cc8d5f2753723b1a202d86";
static {
try {
// Decode the seed into bytes.
byte[] bytes = Hex.decodeHex(HEX_SEED);
// Create long seeds
DataInputStream dis = new DataInputStream(new
ByteArrayInputStream(bytes));
long[] longSeed = new long[bytes.length / 8];
if (longSeed.length < 10) {
throw new Exception("Not enough seed bytes");
}
for (int i = 0; i < longSeed.length; i++) {
longSeed[i] = dis.readLong();
}
dis.close();
// Create int seeds
dis = new DataInputStream(new ByteArrayInputStream(bytes));
int[] intSeed = new int[bytes.length / 4];
for (int i = 0; i < intSeed.length; i++) {
intSeed[i] = dis.readInt();
}
dis.close();
// "int"-based RNGs.
add(LIST32, new JDKRandom(longSeed[0]));
add(LIST32, new MersenneTwister(intSeed));
add(LIST32, new Well512a(intSeed));
add(LIST32, new Well1024a(intSeed));
add(LIST32, new Well19937a(intSeed));
add(LIST32, new Well19937c(intSeed));
add(LIST32, new Well44497a(intSeed));
add(LIST32, new Well44497b(intSeed));
add(LIST32, new ISAACRandom(intSeed));
add(LIST32, new MultiplyWithCarry256(intSeed));
add(LIST32, new KISSRandom(intSeed));
// ... add more here.
// "long"-based RNGs.
add(LIST64, new SplitMix64(longSeed[0]));
add(LIST64, new XorShift1024Star(longSeed));
add(LIST64, new TwoCmres(intSeed[0]));
add(LIST64, new TwoCmres(intSeed[0], 5, 8));
add(LIST64, new MersenneTwister64(longSeed));
// ... add more here.
// Do not modify the remaining statements.
// Complete list.
LIST.addAll(LIST32);
LIST.addAll(LIST64);
} catch (Exception e) {
System.err.println("Unexpected exception while creating the list of
generators: " + e);
e.printStackTrace(System.err);
throw new RuntimeException(e);
}
}
{code}
The first try did not work for a TwoCmres and MersenneTwister. I'll do some
more testing of this idea.
> CachedUniformRandomProvider for nextBoolean() and nextInt()
> -----------------------------------------------------------
>
> Key: RNG-57
> URL: https://issues.apache.org/jira/browse/RNG-57
> Project: Commons RNG
> Issue Type: Improvement
> Components: sampling
> Affects Versions: 1.2
> Reporter: Alex D Herbert
> Priority: Minor
> Labels: performance
>
> Implement a wrapper around a {{UniformRandomProvider}} that can cache the
> underlying source of random bytes for use in the methods {{nextBoolean()}}
> and {{nextInt()}} (in the case of {{LongProvider}}). E.g.
> {code:java}
> LongProvider provider = RandomSource.create(RandomSource.SPLIT_MIX_64);
> CachedLongProvider rng = new CachedLongProvider(provider);
> // Uses cached nextLong() 64 times
> rng.nextBoolean();
> // Uses cached nextLong() twice
> rng.nextInt();
> IntProvider provider = RandomSource.create(RandomSource.KISS);
> CachedIntProvider rng2 = new CachedIntProvider(provider);
> // Uses cached nextInt() 32 times
> rng2.nextBoolean();
> // This could be wrapped by a factory method:
> UniformRandomProvider rng = CachedUniformRandomProviderFactory.wrap(
> // Any supported source: IntProvider or LongProvider
> RandomSource.create(RandomSource...));
> {code}
> The implementation should be speed tested to determine the benefit for
> {{nextBoolean()}} and if {{nextInt()}} can be improved for {{LongProviders}}.
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