File size: 7,630 Bytes
b1b3bae
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
#region Copyright � 2009, De Santiago-Castillo JA. All rights reserved.

//Copyright � 2009 Jose Antonio De Santiago-Castillo 
//E-mail:JAntonioDeSantiago@gmail.com
//Web: www.DotNumerics.com
//
#endregion

using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;

//IBM Def
//A general band matrix has its nonzero elements arranged uniformly near the diagonal, such that: 

//aij = 0    if (i-j) > ml or (j-i) > mu 
//where ml and mu are the lower and upper band widths, respectively, and ml+mu+1 is the total band width. 


namespace DotNumerics.LinearAlgebra
{
    /// <summary>
    /// Represents a Band Matrix.
    /// </summary>
    public sealed class BandMatrix : BaseBandMatrix
    {

        #region  Public Constructors


        /// <summary>
        /// Initializes a new instance of the BandMatrix class of the given size.
        /// </summary>
        /// <param name="rows">Number of rows.</param>
        /// <param name="columns">Number of columns.</param>
        /// <param name="lowerBandWidth">Number of bands below the main diagonal</param>
        /// <param name="upperBandWidth">Number of bands above the main diagonal</param>
        public BandMatrix(int rows, int columns, int lowerBandWidth, int upperBandWidth) : base(rows, columns, lowerBandWidth, upperBandWidth) { }

        /// <summary>
        /// Initializes a new instance of the BandMatrix class of the given size using a array
        /// </summary>
        /// <param name="rows">Number of rows.</param>
        /// <param name="columns">Number of columns.</param>
        /// <param name="lowerBandWidth">Number of bands below the main diagonal</param>
        /// <param name="upperBandWidth">Number of bands above the main diagonal</param>
        /// <param name="Data">The matix data </param>
        internal BandMatrix(int rows, int columns, int lowerBandWidth, int upperBandWidth, double[] Data) : base(rows, columns, lowerBandWidth, upperBandWidth, Data) { }

        #endregion




        #region Overloading Operators


        /// <summary>
        /// Matrix addition.
        /// </summary>
        /// <param name="A">The left side matrix of the addition operator.</param>
        /// <param name="B">The right side matrix of the addition operator.</param>
        /// <returns>A matrix that represents the result of the matrix addition.</returns>
        public static BandMatrix operator +(BandMatrix A, BandMatrix B)
        {
            if (B.RowCount != A.RowCount || B.ColumnCount != A.ColumnCount || B.LowerBandWidth != A.LowerBandWidth || B.UpperBandWidth != A.UpperBandWidth)
            {
                throw new System.ArgumentException("Matrix dimensions are not valid.");
            }

            BandMatrix C = new BandMatrix(A.RowCount, A.ColumnCount, A.LowerBandWidth, B.UpperBandWidth);

            double[] AData = A.Data;
            double[] BData = B.Data;
            double[] CData = C.Data;

            for (int i = 0; i < AData.Length; i++)
            {
                CData[i] = AData[i] + BData[i];
            }

            return C;
        }

        /// <summary>
        /// Matrix subtraction.
        /// </summary>
        /// <param name="A"> The left side matrix of the subtraction operator.</param>
        /// <param name="B">The right side matrix of the subtraction operator.</param>
        /// <returns>A matrix that represents the result of the matrix subtraction.</returns>
        public static BandMatrix operator -(BandMatrix A, BandMatrix B)
        {
            if (B.RowCount != A.RowCount || B.ColumnCount != A.ColumnCount || B.LowerBandWidth != A.LowerBandWidth || B.UpperBandWidth != A.UpperBandWidth)
            {
                throw new System.ArgumentException("Matrix dimensions are not valid.");
            }

            BandMatrix C = new BandMatrix(A.RowCount, A.ColumnCount, A.LowerBandWidth, B.UpperBandWidth);

            double[] AData = A.Data;
            double[] BData = B.Data;
            double[] CData = C.Data;

            for (int i = 0; i < AData.Length; i++)
            {
                CData[i] = AData[i] - BData[i];
            }

            return C;
        }

        #region Scalar-Matrix Multiplication

        /// <summary>
        /// Scalar-Matrix multiplication.
        /// </summary>
        /// <param name="s"> The left side scalar of the multiplication operator.</param>
        /// <param name="A">The right side matrix of the multiplication operator.</param>
        /// <returns>A matrix that represents the result of the multiplication.</returns>
        public static BandMatrix operator *(double s, BandMatrix A)
        {
            BandMatrix C = new BandMatrix(A.RowCount, A.ColumnCount, A.LowerBandWidth, A.UpperBandWidth);

            double[] AData = A.Data;
            double[] CData = C.Data;


            Matrix.MultiplicationSM(s, AData, CData);

            return C;
        }

        #endregion

        #endregion



        #region Public Methods

        /// <summary>
        /// Creates a copy of the matrix.
        /// </summary>
        /// <returns>The copy of the Matrix.</returns>
        public BandMatrix Clone()
        {
            BandMatrix NewBandMatix = new BandMatrix(this._RowCount, this._ColumnCount, this.MeLowerBandWidth, this.MeUpperBandWidth, this._Data);
            return NewBandMatix;
        }


        internal Matrix GetBandPackedMatrix()
        {
            int MatrixRows = 2 * this.MeLowerBandWidth + this.MeUpperBandWidth + 1;
            int MatrixColumns = this._ColumnCount;
            Matrix MatrixBandStorageExt = new Matrix(MatrixRows, MatrixColumns);
            double[] GeneralBandStorage = MatrixBandStorageExt.Data;
            int Index;
            int TempInt = this.MeLowerBandWidth + this.MeUpperBandWidth + 1;
            for (int colum = 1; colum <= MatrixColumns; colum++)
            {
                for (int row = Math.Max(1, colum - this.MeUpperBandWidth); row <= Math.Min(this._ColumnCount, colum + this.MeLowerBandWidth); row++)
                {
                    Index = TempInt + row - colum;
                    GeneralBandStorage[Index - 1 + (colum - 1) * MatrixRows] = this._Data[row - 1 + (colum - 1) * this._RowCount];
                }
            }
            return MatrixBandStorageExt;
        }


        #region Static methods


        /// <summary>Generate a BandMatrix with random elements</summary>
        /// <param name="rows">Number of rows.</param>
        /// <param name="columns">Number of columns.</param>
        /// <param name="lowerBandWidth">Number of bands below the main diagonal</param>
        /// <param name="upperBandWidth">Number of bands above the main diagonal</param>
        public static BandMatrix Random(int rows, int columns, int lowerBandWidth, int upperBandWidth)
        {
            System.Random random = new System.Random();

            BandMatrix X = new BandMatrix(rows, columns, lowerBandWidth, upperBandWidth);

            double[] XData = X.Data;

            for (int j = 0; j < X.ColumnCount; j++)
            {
                for (int i = 0; i < X.RowCount; i++)
                {
                    X[i, j] = random.NextDouble();
                }
            }
            return X;
        }

        #endregion

        #endregion

        #region Private Methods

        #endregion


    }
}