1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22 package org.hipparchus.distribution.multivariate;
23
24 import org.hipparchus.distribution.MultivariateRealDistribution;
25 import org.hipparchus.exception.LocalizedCoreFormats;
26 import org.hipparchus.exception.MathIllegalArgumentException;
27 import org.hipparchus.random.RandomGenerator;
28
29 /**
30 * Base class for multivariate probability distributions.
31 */
32 public abstract class AbstractMultivariateRealDistribution
33 implements MultivariateRealDistribution {
34 /** RNG instance used to generate samples from the distribution. */
35 protected final RandomGenerator random;
36 /** The number of dimensions or columns in the multivariate distribution. */
37 private final int dimension;
38
39 /** Simple constructor.
40 * @param rng Random number generator.
41 * @param n Number of dimensions.
42 */
43 protected AbstractMultivariateRealDistribution(RandomGenerator rng,
44 int n) {
45 random = rng;
46 dimension = n;
47 }
48
49 /** {@inheritDoc} */
50 @Override
51 public void reseedRandomGenerator(long seed) {
52 random.setSeed(seed);
53 }
54
55 /** {@inheritDoc} */
56 @Override
57 public int getDimension() {
58 return dimension;
59 }
60
61 /** {@inheritDoc} */
62 @Override
63 public abstract double[] sample();
64
65 /** {@inheritDoc} */
66 @Override
67 public double[][] sample(final int sampleSize) {
68 if (sampleSize <= 0) {
69 throw new MathIllegalArgumentException(LocalizedCoreFormats.NUMBER_OF_SAMPLES,
70 sampleSize);
71 }
72 final double[][] out = new double[sampleSize][dimension];
73 for (int i = 0; i < sampleSize; i++) {
74 out[i] = sample();
75 }
76 return out;
77 }
78 }