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 * http://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 package org.apache.commons.statistics.distribution;
18
19 /**
20 * Utilities for argument validation.
21 */
22 final class ArgumentUtils {
23 /** No instances. */
24 private ArgumentUtils() {}
25
26 /**
27 * Checks if the value {@code x} is finite and strictly positive.
28 *
29 * @param x Value
30 * @return true if {@code x > 0} and is finite
31 */
32 static boolean isFiniteStrictlyPositive(double x) {
33 return x > 0 && x < Double.POSITIVE_INFINITY;
34 }
35
36 /**
37 * Check the probability {@code p} is in the interval {@code [0, 1]}.
38 *
39 * @param p Probability
40 * @throws IllegalArgumentException if {@code p < 0} or {@code p > 1}
41 */
42 static void checkProbability(double p) {
43 if (p >= 0 && p <= 1) {
44 return;
45 }
46 // Out-of-range or NaN
47 throw new DistributionException(DistributionException.INVALID_PROBABILITY, p);
48 }
49 }