Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||
IntegerDistribution |
|
| 1.0;1 |
1 | /* |
|
2 | * Copyright 2004 The Apache Software Foundation. |
|
3 | * |
|
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
|
5 | * you may not use this file except in compliance with the License. |
|
6 | * You may obtain a copy of the License at |
|
7 | * |
|
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
|
9 | * |
|
10 | * Unless required by applicable law or agreed to in writing, software |
|
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
|
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
|
13 | * See the License for the specific language governing permissions and |
|
14 | * limitations under the License. |
|
15 | */ |
|
16 | package org.apache.commons.math.distribution; |
|
17 | ||
18 | import org.apache.commons.math.MathException; |
|
19 | ||
20 | /** |
|
21 | * Interface for discrete distributions of integer-valued random variables. |
|
22 | * |
|
23 | * @version $Revision$ $Date: 2005-02-26 05:11:52 -0800 (Sat, 26 Feb 2005) $ |
|
24 | */ |
|
25 | public interface IntegerDistribution extends DiscreteDistribution { |
|
26 | /** |
|
27 | * For a random variable X whose values are distributed according |
|
28 | * to this distribution, this method returns P(X = x). In other words, this |
|
29 | * method represents the probability mass function for the distribution. |
|
30 | * |
|
31 | * @param x the value at which the probability density function is evaluated. |
|
32 | * @return the value of the probability density function at x |
|
33 | */ |
|
34 | double probability(int x); |
|
35 | ||
36 | /** |
|
37 | * For a random variable X whose values are distributed according |
|
38 | * to this distribution, this method returns P(X ≤ x). In other words, |
|
39 | * this method represents the probability distribution function, or PDF |
|
40 | * for the distribution. |
|
41 | * |
|
42 | * @param x the value at which the PDF is evaluated. |
|
43 | * @return PDF for this distribution. |
|
44 | * @throws MathException if the cumulative probability can not be |
|
45 | * computed due to convergence or other numerical errors. |
|
46 | */ |
|
47 | double cumulativeProbability(int x) throws MathException; |
|
48 | ||
49 | /** |
|
50 | * For this distribution, X, this method returns P(x0 ≤ X ≤ x1). |
|
51 | * @param x0 the inclusive, lower bound |
|
52 | * @param x1 the inclusive, upper bound |
|
53 | * @return the cumulative probability. |
|
54 | * @throws MathException if the cumulative probability can not be |
|
55 | * computed due to convergence or other numerical errors. |
|
56 | * @throws IllegalArgumentException if x0 > x1 |
|
57 | */ |
|
58 | double cumulativeProbability(int x0, int x1) throws MathException; |
|
59 | ||
60 | /** |
|
61 | * For this distribution, X, this method returns the largest x such that |
|
62 | * P(X ≤ x) <= p. |
|
63 | * <p> |
|
64 | * Note that this definition implies: <ul> |
|
65 | * <li> If there is a minimum value, <code>m</code>, with postive |
|
66 | * probablility under (the density of) X, then <code>m - 1</code> is |
|
67 | * returned by <code>inverseCumulativeProbability(0).</code> If there is |
|
68 | * no such value <code>m, Integer.MIN_VALUE</code> is |
|
69 | * returned.</li> |
|
70 | * <li> If there is a maximum value, <code>M</code>, such that |
|
71 | * P(X ≤ M) =1, then <code>M</code> is returned by |
|
72 | * <code>inverseCumulativeProbability(1).</code> |
|
73 | * If there is no such value, <code>M, Integer.MAX_VALUE</code> is |
|
74 | * returned.</li></ul> |
|
75 | * |
|
76 | * @param p the cumulative probability. |
|
77 | * @return the largest x such that P(X ≤ x) <= p |
|
78 | * @throws MathException if the inverse cumulative probability can not be |
|
79 | * computed due to convergence or other numerical errors. |
|
80 | * @throws IllegalArgumentException if p is not between 0 and 1 (inclusive) |
|
81 | */ |
|
82 | int inverseCumulativeProbability(double p) throws MathException; |
|
83 | } |