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Posted to commits@commons.apache.org by ah...@apache.org on 2019/10/21 16:41:10 UTC
[commons-rng] branch master updated (b571fa9 -> 524163e)
This is an automated email from the ASF dual-hosted git repository.
aherbert pushed a change to branch master
in repository https://gitbox.apache.org/repos/asf/commons-rng.git.
from b571fa9 Results command to summarise PractRand failure length if all failed.
new 7f2d39b Substitute custom rotl function for Long.rotateLeft.
new 524163e Removed unreachable code from seeding routine.
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Summary of changes:
.../apache/commons/rng/core/source64/TwoCmres.java | 15 +-----------
.../commons/rng/core/source64/TwoCmresTest.java | 27 ++++++++++++++++++++++
2 files changed, 28 insertions(+), 14 deletions(-)
[commons-rng] 02/02: Removed unreachable code from seeding routine.
Posted by ah...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-rng.git
commit 524163e36abdd21c9179275abc175521c89e7c90
Author: aherbert <ah...@apache.org>
AuthorDate: Mon Oct 21 17:41:05 2019 +0100
Removed unreachable code from seeding routine.
The code comment is clear that the two values for seeding are positive
16-bit integers. A test has been added to verify a single bit change in
the seed makes the output different. Thus all 32-bits of the seed are
used to construct two 16-bit integers.
---
.../apache/commons/rng/core/source64/TwoCmres.java | 5 ----
.../commons/rng/core/source64/TwoCmresTest.java | 27 ++++++++++++++++++++++
2 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/TwoCmres.java b/commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/TwoCmres.java
index c9c633f..6fd92ef 100644
--- a/commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/TwoCmres.java
+++ b/commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/TwoCmres.java
@@ -150,11 +150,6 @@ public class TwoCmres extends LongProvider {
final int xMax = (seed & 0xffff) + (SEED_GUARD & 0xff);
final int yMax = (seed >>> 16) + (SEED_GUARD & 0xff);
- if (xMax < 0 ||
- yMax < 0) {
- throw new IllegalStateException(INTERNAL_ERROR_MSG);
- }
-
xx = x.getStart();
for (int i = xMax; i > 0; i--) {
xx = x.transform(xx);
diff --git a/commons-rng-core/src/test/java/org/apache/commons/rng/core/source64/TwoCmresTest.java b/commons-rng-core/src/test/java/org/apache/commons/rng/core/source64/TwoCmresTest.java
index a1d8202..f1d2ed5 100644
--- a/commons-rng-core/src/test/java/org/apache/commons/rng/core/source64/TwoCmresTest.java
+++ b/commons-rng-core/src/test/java/org/apache/commons/rng/core/source64/TwoCmresTest.java
@@ -40,6 +40,33 @@ public class TwoCmresTest {
}
}
+ /**
+ * This test targets the seeding procedure to verify any bit of the input seed contributes
+ * to the output. Note: The seeding routine creates 2 16-bit integers from the 32-bit seed,
+ * thus a change of any single bit should make a different output.
+ */
+ @Test
+ public void testSeedingWithASingleBitProducesDifferentOutputFromZeroSeed() {
+ final int n = 100;
+
+ // Output with a zero seed
+ final long[] values = new long[n];
+ final TwoCmres rng = new TwoCmres(0);
+ for (int i = 0; i < n; i++) {
+ values[i] = rng.nextLong();
+ }
+
+ // Seed with a single bit
+ for (int bit = 0; bit < 32; bit++) {
+ final int seed = 1 << bit;
+
+ final TwoCmres rng1 = new TwoCmres(seed);
+ for (int i = 0; i < n; i++) {
+ Assert.assertNotEquals(values[i], rng1.nextLong());
+ }
+ }
+ }
+
@Test
public void testSubcycleGeneratorsMustBeDifferent() {
final int max = TwoCmres.numberOfSubcycleGenerators();
[commons-rng] 01/02: Substitute custom rotl function for
Long.rotateLeft.
Posted by ah...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-rng.git
commit 7f2d39b7d09be98ba9ffe17e7ebfa2ad31c00438
Author: aherbert <ah...@apache.org>
AuthorDate: Mon Oct 21 17:17:17 2019 +0100
Substitute custom rotl function for Long.rotateLeft.
---
.../java/org/apache/commons/rng/core/source64/TwoCmres.java | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/TwoCmres.java b/commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/TwoCmres.java
index 6c50d03..c9c633f 100644
--- a/commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/TwoCmres.java
+++ b/commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/TwoCmres.java
@@ -223,19 +223,11 @@ public class TwoCmres extends LongProvider {
long transform(long state) {
long s = state;
s *= multiply;
- s = rotl(s);
+ s = Long.rotateLeft(s, rotate);
s -= state;
return s;
}
- /**
- * @param state State.
- * @return the rotated state.
- */
- private long rotl(long state) {
- return (state << rotate) | (state >>> (64 - rotate));
- }
-
/** Factory. */
static class Factory {
/** List of good "Cmres" subcycle generators. */