Java Reference

Java Reference

WeightedSumExpression.java
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1// Copyright 2010-2021 Google LLC
2// Licensed under the Apache License, Version 2.0 (the "License");
3// you may not use this file except in compliance with the License.
4// You may obtain a copy of the License at
5//
6// http://www.apache.org/licenses/LICENSE-2.0
7//
8// Unless required by applicable law or agreed to in writing, software
9// distributed under the License is distributed on an "AS IS" BASIS,
10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11// See the License for the specific language governing permissions and
12// limitations under the License.
13
14package com.google.ortools.sat;
15
17public final class WeightedSumExpression implements LinearExpr {
18 private final int[] variablesIndices;
19 private final long[] coefficients;
20 private final long offset;
21
22 public WeightedSumExpression(int[] variablesIndices, long[] coefficients, long offset) {
23 this.variablesIndices = variablesIndices;
24 this.coefficients = coefficients;
25 this.offset = offset;
26 }
27
28 @Override
29 public LinearExpr build() {
30 return this;
31 }
32
33 @Override
34 public int numElements() {
35 return variablesIndices.length;
36 }
37
38 @Override
39 public int getVariableIndex(int index) {
40 if (index < 0 || index >= variablesIndices.length) {
41 throw new IllegalArgumentException("wrong index in LinearExpr.getVariable(): " + index);
42 }
43 return variablesIndices[index];
44 }
45
46 @Override
47 public long getCoefficient(int index) {
48 if (index < 0 || index >= variablesIndices.length) {
49 throw new IllegalArgumentException("wrong index in LinearExpr.getCoefficient(): " + index);
50 }
51 return coefficients[index];
52 }
53
54 @Override
55 public long getOffset() {
56 return offset;
57 }
58}
A specialized linear expression: sum(ai * xi) + b.
long getCoefficient(int index)
Returns the ith coefficient.
WeightedSumExpression(int[] variablesIndices, long[] coefficients, long offset)
int numElements()
Returns the number of terms (excluding the constant one) in this expression.
LinearExpr build()
Builds a linear expression.
long getOffset()
Returns the constant part of the expression.
int getVariableIndex(int index)
Returns the index of the ith variable.
A linear expression (sum (ai * xi) + b).
Definition: LinearExpr.java:19