@@ -43,7 +44,7 @@ * The generator supports two modes: *
* This operation can be performed in O(1).
*
* @param index the index in the sequence to skip to
- * @return the i-th point in the Halton sequence
- * @throws org.apache.commons.math4.legacy.exception.NotPositiveException NotPositiveException if index < 0
+ * @return the copy of this sequence
+ * @throws NotPositiveException if index < 0
*/
- public double[] skipTo(final int index) {
+ @Override
+ public LowDiscrepancySequence jump(final long index) throws NotPositiveException {
+ if(index < 0) {
+ throw new NotPositiveException(index);
+ }
+ HaltonSequenceGenerator copy = this.copy();
+ copy.performJump(index);
+ return copy;
+ }
+
+ /**
+ * do jump at the index
+ * @param index
+ */
+ private void performJump(long index) {
count = index;
- return get();
}
/**
- * Returns the index i of the next point in the Halton sequence that will be returned
- * by calling {@link #get()}.
- *
- * @return the index of the next point
+ * private constructor avoid side effects
+ * @return copy of HaltonSequenceGenerator
*/
- public int getNextIndex() {
- return count;
+ private HaltonSequenceGenerator copy() {
+ return new HaltonSequenceGenerator(this);
}
+
+
}
diff --git a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/quasirandom/LowDiscrepancySequence.java b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/quasirandom/LowDiscrepancySequence.java
new file mode 100644
index 0000000000..0d6c834c82
--- /dev/null
+++ b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/quasirandom/LowDiscrepancySequence.java
@@ -0,0 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.math4.legacy.quasirandom;
+
+import java.util.function.Supplier;
+
+/** Interface to Low Discrepancy Sequence generator and supplier.
+ * Supplier of a low discrepancy vectors.
+ * Offers navigation through underlying sequence.
+ */
+public interface LowDiscrepancySequence extends Supplier
@@ -261,7 +269,7 @@ public double[] get() {
// find the index c of the rightmost 0
int c = 1;
- int value = count - 1;
+ long value = count - 1;
while ((value & 1) == 1) {
value >>= 1;
c++;
@@ -281,15 +289,30 @@ public double[] get() {
* This operation can be performed in O(1).
*
* @param index the index in the sequence to skip to
- * @return the i-th point in the Sobol sequence
- * @throws org.apache.commons.math4.legacy.exception.NotPositiveException NotPositiveException if index < 0
+ * @return the sequence it self
+ * @throws NotPositiveException if index < 0
*/
- public double[] skipTo(final int index) {
+ @Override
+ public LowDiscrepancySequence jump(final long index) throws NotPositiveException {
+ if(index < 0) {
+ throw new NotPositiveException(index);
+ }
+
+ SobolSequenceGenerator copy = this.copy();
+ copy.performJump(index);
+ return copy;
+ }
+
+ /**
+ * Do jump at the index.
+ * @param index
+ */
+ private void performJump(long index) {
if (index == 0) {
// reset x vector
Arrays.fill(x, 0);
} else {
- final int i = index - 1;
+ final long i = index - 1;
final long grayCode = i ^ (i >> 1); // compute the gray code of i = i XOR floor(i / 2)
for (int j = 0; j < dimension; j++) {
long result = 0;
@@ -307,17 +330,14 @@ public double[] skipTo(final int index) {
}
}
count = index;
- return get();
}
/**
- * Returns the index i of the next point in the Sobol sequence that will be returned
- * by calling {@link #get()}.
- *
- * @return the index of the next point
+ * Private constructor avoid side effects.
+ * @return copy of LowDiscrepancySequence
*/
- public int getNextIndex() {
- return count;
+ private SobolSequenceGenerator copy() {
+ return new SobolSequenceGenerator(this);
}
}
diff --git a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/quasirandom/package-info.java b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/quasirandom/package-info.java
new file mode 100644
index 0000000000..ef4d50192e
--- /dev/null
+++ b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/quasirandom/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * Contains quasi random sequences.
+ */
+package org.apache.commons.math4.legacy.quasirandom;
diff --git a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/HaltonSequenceGeneratorTest.java b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/quasirandom/HaltonSequenceGeneratorTest.java
similarity index 85%
rename from commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/HaltonSequenceGeneratorTest.java
rename to commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/quasirandom/HaltonSequenceGeneratorTest.java
index 4dd800b41b..042df96902 100644
--- a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/HaltonSequenceGeneratorTest.java
+++ b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/quasirandom/HaltonSequenceGeneratorTest.java
@@ -14,12 +14,13 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/
-package org.apache.commons.math4.legacy.random;
+package org.apache.commons.math4.legacy.quasirandom;
-import org.junit.Assert;
import org.apache.commons.math4.legacy.exception.DimensionMismatchException;
+import org.apache.commons.math4.legacy.exception.NotPositiveException;
import org.apache.commons.math4.legacy.exception.NullArgumentException;
import org.apache.commons.math4.legacy.exception.OutOfRangeException;
+import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
@@ -63,7 +64,6 @@ public void test3DReference() {
for (int i = 0; i < referenceValues.length; i++) {
double[] result = generator.get();
Assert.assertArrayEquals(referenceValues[i], result, 1e-3);
- Assert.assertEquals(i + 1, generator.getNextIndex());
}
}
@@ -73,7 +73,6 @@ public void test2DUnscrambledReference() {
for (int i = 0; i < referenceValuesUnscrambled.length; i++) {
double[] result = generator.get();
Assert.assertArrayEquals(referenceValuesUnscrambled[i], result, 1e-3);
- Assert.assertEquals(i + 1, generator.getNextIndex());
}
}
@@ -119,16 +118,30 @@ public void testConstructor2() throws Exception{
}
@Test
- public void testSkip() {
- double[] result = generator.skipTo(5);
+ public void testJump() {
+ LowDiscrepancySequence copyOfSeq = generator.jump(5);
+ double[] result = copyOfSeq.get();
Assert.assertArrayEquals(referenceValues[5], result, 1e-3);
- Assert.assertEquals(6, generator.getNextIndex());
+
for (int i = 6; i < referenceValues.length; i++) {
- result = generator.get();
+ result = copyOfSeq.get();
Assert.assertArrayEquals(referenceValues[i], result, 1e-3);
- Assert.assertEquals(i + 1, generator.getNextIndex());
}
}
+
+ @Test(expected = NotPositiveException.class)
+ public void testJumpNegativeIndex() {
+ LowDiscrepancySequence copyOfSeq = generator.jump(-5);
+ }
+
+
+
+ @Test
+ public void testFirstSupplying() {
+ LowDiscrepancySequence sequence = new HaltonSequenceGenerator(3);
+ Assert.assertArrayEquals(new double[]{0.0, 0.0, 0.0}, sequence.get(),1e-6);
+ }
+
}
diff --git a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/SobolSequenceGeneratorTest.java b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/quasirandom/SobolSequenceGeneratorTest.java
similarity index 82%
rename from commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/SobolSequenceGeneratorTest.java
rename to commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/quasirandom/SobolSequenceGeneratorTest.java
index 11c45a30de..57be1376a1 100644
--- a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/SobolSequenceGeneratorTest.java
+++ b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/quasirandom/SobolSequenceGeneratorTest.java
@@ -14,15 +14,14 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/
-package org.apache.commons.math4.legacy.random;
-
-import org.junit.Assert;
-
-import java.io.InputStream;
+package org.apache.commons.math4.legacy.quasirandom;
+import org.apache.commons.math4.legacy.exception.NotPositiveException;
import org.apache.commons.math4.legacy.exception.OutOfRangeException;
+import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
+import java.io.InputStream;
public class SobolSequenceGeneratorTest {
private static final String RESOURCE_NAME = "/assets/org/apache/commons/math4/legacy/random/new-joe-kuo-6.21201";
@@ -52,7 +51,6 @@ public void test3DReference() {
for (int i = 0; i < referenceValues.length; i++) {
double[] result = generator.get();
Assert.assertArrayEquals(referenceValues[i], result, 1e-6);
- Assert.assertEquals(i + 1, generator.getNextIndex());
}
}
@@ -92,16 +90,26 @@ public void testConstructor2() throws Exception{
}
@Test
- public void testSkip() {
- double[] result = generator.skipTo(5);
+ public void testJump() {
+ LowDiscrepancySequence copyOfSeq = generator.jump(5);
+ double[] result = copyOfSeq.get();
Assert.assertArrayEquals(referenceValues[5], result, 1e-6);
- Assert.assertEquals(6, generator.getNextIndex());
for (int i = 6; i < referenceValues.length; i++) {
- result = generator.get();
+ result = copyOfSeq.get();
Assert.assertArrayEquals(referenceValues[i], result, 1e-6);
- Assert.assertEquals(i + 1, generator.getNextIndex());
}
}
+ @Test(expected = NotPositiveException.class)
+ public void testJumpNegativeIndex() {
+ LowDiscrepancySequence copyOfSeq = generator.jump(-5);
+ }
+
+ @Test
+ public void testFirstSupplying() {
+ LowDiscrepancySequence sequence = new SobolSequenceGenerator(3);
+ Assert.assertArrayEquals(new double[]{0.0, 0.0, 0.0}, sequence.get(),1e-6);
+ }
+
}
*
*
* @see Sobol sequence (Wikipedia)
@@ -53,7 +53,8 @@
*
* @since 3.3
*/
-public class SobolSequenceGenerator implements Supplier