01: /*
02: * Copyright 2003-2004 The Apache Software Foundation.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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: /**
19: * Base interface for discrete distributions.
20: *
21: * @version $Revision: 155427 $ $Date: 2005-02-26 06:11:52 -0700 (Sat, 26 Feb 2005) $
22: */
23: public interface DiscreteDistribution extends Distribution {
24: /**
25: * For a random variable X whose values are distributed according
26: * to this distribution, this method returns P(X = x). In other words, this
27: * method represents the probability mass function, or PMF for the distribution.
28: *
29: * @param x the value at which the probability mass function is evaluated.
30: * @return the value of the probability mass function at x
31: */
32: double probability(double x);
33: }
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