C#,数值计算,矩阵的行列式(Determinant)、伴随矩阵(Adjoint)与逆矩阵(Inverse)的算法与源代码

本文发布矩阵(Matrix)的一些初级算法。

一、矩阵的行列式(Determinant)

矩阵行列式是指矩阵的全部元素构成的行列式,设A=(a)是数域P上的一个n阶矩阵,则所有A=(a)中的元素组成的行列式称为矩阵A的行列式,记为|A|或det(A)。若A,B是数域P上的两个n阶矩阵,k是P中的任一个数,则|AB|=|A||B|,|kA|=kⁿ|A|,|A*|=|A|,其中A*是A的伴随矩阵;若A是可逆矩阵,则|A|=|A|。

/// <summary>

/// 计算 A[p,q] 位于 [,]temp 的块辅因子

/// </summary>

/// <param name="matrix"></param>

/// <param name="temp"></param>

/// <param name="p"></param>

/// <param name="q"></param>

/// <param name="n"></param>

private static void BlockCofactor(double[,] matrix, ref double[,] temp, int p, int q, int n)

{

int i = 0;

int j = 0;

for (int row = 0; row < n; row++)

{

for (int col = 0; col < n; col++)

{

if (row != p && col != q)

{

temp[i, j++] = matrix[row, col];

if (j == (n - 1))

{

j = 0;

i++;

}

}

}

}

}

/// <summary>

/// 求矩阵行列式(递归算法)

/// </summary>

/// <param name="N"></param>

/// <param name="matrix"></param>

/// <param name="n"></param>

/// <returns></returns>

public static double Determinant(int N, double[,] matrix, int n)

{

if (n == 1)

{

return matrix[0, 0];

}

double D = 0.0;

double[,] temp = new double[N, N];

int sign = 1;

for (int f = 0; f < n; f++)

{

BlockCofactor(matrix, ref temp, 0, f, n);

D += sign * matrix[0, f] * Determinant(N, temp, n - 1);

sign = -sign;

}

return D;

}

cs 复制代码
/// <summary>
/// 计算 A[p,q] 位于 [,]temp 的块辅因子
/// </summary>
/// <param name="matrix"></param>
/// <param name="temp"></param>
/// <param name="p"></param>
/// <param name="q"></param>
/// <param name="n"></param>
private static void BlockCofactor(double[,] matrix, ref double[,] temp, int p, int q, int n)
{
    int i = 0;
    int j = 0;

    for (int row = 0; row < n; row++)
    {
        for (int col = 0; col < n; col++)
        {
            if (row != p && col != q)
            {
                temp[i, j++] = matrix[row, col];
                if (j == (n - 1))
                {
                    j = 0;
                    i++;
                }
            }
        }
    }
}

/// <summary>
/// 求矩阵行列式(递归算法)
/// </summary>
/// <param name="N"></param>
/// <param name="matrix"></param>
/// <param name="n"></param>
/// <returns></returns>
public static double Determinant(int N, double[,] matrix, int n)
{
    if (n == 1)
    {
        return matrix[0, 0];
    }

    double D = 0.0;
    double[,] temp = new double[N, N];
    int sign = 1;
    for (int f = 0; f < n; f++)
    {
        BlockCofactor(matrix, ref temp, 0, f, n);
        D += sign * matrix[0, f] * Determinant(N, temp, n - 1);
        sign = -sign;
    }
    return D;
}

二、矩阵的伴随矩阵(Adjoint Matrix)

一个方形矩阵的伴随矩阵是一个类似于逆矩阵的概念。如果二维矩阵可逆,那么它的逆矩阵和它的伴随矩阵之间只差一个系数,对多维矩阵也存在这个规律。然而,伴随矩阵对不可逆的矩阵也有定义,并且不需要用到除法。

/// <summary>

/// 伴随矩阵

/// </summary>

/// <param name="A"></param>

/// <param name="adj"></param>

public static void Adjoint(double[,] matrix, out double[,] adjoint)

{

int N = matrix.GetLength(0);

adjoint = new double[N, N];

if (N == 1)

{

adjoint[0, 0] = 1.0;

return;

}

int sign = 1;

double[,] temp = new double[N, N];

for (int i = 0; i < N; i++)

{

for (int j = 0; j < N; j++)

{

BlockCofactor(matrix, ref temp, i, j, N);

sign = ((i + j) % 2 == 0) ? 1 : -1;

adjoint[j, i] = (sign) * (Determinant(N, temp, N - 1));

}

}

}

cs 复制代码
/// <summary>
/// 伴随矩阵
/// </summary>
/// <param name="A"></param>
/// <param name="adj"></param>
public static void Adjoint(double[,] matrix, out double[,] adjoint)
{
    int N = matrix.GetLength(0);
    adjoint = new double[N, N];

    if (N == 1)
    {
        adjoint[0, 0] = 1.0;
        return;
    }

    int sign = 1;
    double[,] temp = new double[N, N];
    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            BlockCofactor(matrix, ref temp, i, j, N);
            sign = ((i + j) % 2 == 0) ? 1 : -1;
            adjoint[j, i] = (sign) * (Determinant(N, temp, N - 1));
        }
    }
}

三、矩阵的逆矩阵(Inverse Matrix)

设A是一个n阶矩阵,若存在另一个n阶矩阵B,使得: AB=BA=E ,则称方阵A可逆,并称方阵B是A的逆矩阵。矩阵求逆,即求矩阵的逆矩阵。矩阵是线性代数的主要内容,很多实际问题用矩阵的思想去解既简单又快捷。逆矩阵又是矩阵理论的很重要的内容,逆矩阵的求法自然也就成为线性代数研究的主要内容之一。

/// <summary>

/// 矩阵求逆

/// </summary>

/// <param name="A"></param>

/// <param name="inverse"></param>

/// <returns></returns>

public static bool Inverse(double[,] matrix, out double[,] inverse)

{

int N = matrix.GetLength(0);

inverse = new double[N, N];

double det = Determinant(N, matrix, N);

if (det == 0)

{

return false;

}

Adjoint(matrix, out double[,] adj);

for (int i = 0; i < N; i++)

{

for (int j = 0; j < N; j++)

{

inverse[i, j] = adj[i, j] / (double)det;

}

}

return true;

}

cs 复制代码
/// <summary>
/// 矩阵求逆
/// </summary>
/// <param name="A"></param>
/// <param name="inverse"></param>
/// <returns></returns>
public static bool Inverse(double[,] matrix, out double[,] inverse)
{
    int N = matrix.GetLength(0);
    inverse = new double[N, N];

    double det = Determinant(N, matrix, N);
    if (det == 0)
    {
        return false;
    }

    Adjoint(matrix, out double[,] adj);

    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            inverse[i, j] = adj[i, j] / (double)det;
        }
    }
    return true;
}

演算代码:

private void button1_Click(object sender, EventArgs e)

{

double[,] A = {

{5, -2, 2, 7},

{1, 0, 0, 3},

{-3, 1, 5, 0},

{3, -1, -9, 4}

};

double d = Algorithm_Gallery.Determinant(4, A, 4);

StringBuilder sb = new StringBuilder();

sb.Append(Welcome());

sb.AppendLine("1、<b>原始矩阵</b>(Source Matrix):<br>");

sb.Append(Algorithm_Gallery.ToHtml(A));

sb.AppendLine("行列式(Determinant)=" + d + "<br>");

Algorithm_Gallery.Adjoint(A, out double[,] adj);

sb.AppendLine("<br>2、<b>伴随矩阵</b>(Adjoint Matrix):<br>");

sb.Append(Algorithm_Gallery.ToHtml(adj));

Algorithm_Gallery.Inverse(A, out double[,] inv);

sb.AppendLine("<br>3、<b>逆矩阵</b>(Inverse Matrix):<br>");

sb.Append(Algorithm_Gallery.ToHtml(inv));

sb.Append(Bye());

webBrowser1.DocumentText = sb.ToString();

}

cs 复制代码
private void button1_Click(object sender, EventArgs e)
{
    double[,] A = { 
        {5, -2, 2, 7},
        {1, 0, 0, 3},
        {-3, 1, 5, 0},
        {3, -1, -9, 4}
    };

    double d = Algorithm_Gallery.Determinant(4, A, 4);

    StringBuilder sb = new StringBuilder();
    sb.Append(Welcome());
    sb.AppendLine("1、<b>原始矩阵</b>(Source Matrix):<br>");
    sb.Append(Algorithm_Gallery.ToHtml(A));
    sb.AppendLine("行列式(Determinant)=" + d + "<br>");
    
    Algorithm_Gallery.Adjoint(A, out double[,] adj);
    sb.AppendLine("<br>2、<b>伴随矩阵</b>(Adjoint Matrix):<br>");
    sb.Append(Algorithm_Gallery.ToHtml(adj));
    
    Algorithm_Gallery.Inverse(A, out double[,] inv);
    sb.AppendLine("<br>3、<b>逆矩阵</b>(Inverse Matrix):<br>");
    sb.Append(Algorithm_Gallery.ToHtml(inv));
    sb.Append(Bye());
    webBrowser1.DocumentText = sb.ToString();
}

打印矩阵的代码:

public static string ToHtml(double[,] y)

{

int m = y.GetLength(0);

int n = y.GetLength(1);

StringBuilder sb = new StringBuilder();

sb.AppendLine("<style>");

sb.AppendLine("td { padding:5px;text-align:right; }");

sb.AppendLine("</style>");

sb.AppendLine("<table width='100%' border=1 bordercolor='#999999' style='border-collapse:collapse;'>");

for (int i = 0; i < m; i++)

{

sb.AppendLine("<tr>");

for (int j = 0; j < n; j++)

{

sb.AppendLine("<td>" + String.Format("{0:F8}", y[i, j]) + "</td>");

}

sb.AppendLine("</tr>");

}

sb.AppendLine("</table>");

return sb.ToString();

}


POWER BY TRUFFER.CN 50018.COM 315SOFT.COM

cs 复制代码
public static string ToHtml(double[,] y)
{
    int m = y.GetLength(0);
    int n = y.GetLength(1);
    StringBuilder sb = new StringBuilder();
    sb.AppendLine("<style>");
    sb.AppendLine("td { padding:5px;text-align:right; }");
    sb.AppendLine("</style>");
    sb.AppendLine("<table width='100%' border=1 bordercolor='#999999' style='border-collapse:collapse;'>");
    for (int i = 0; i < m; i++)
    {
        sb.AppendLine("<tr>");
        for (int j = 0; j < n; j++)
        {
            sb.AppendLine("<td>" + String.Format("{0:F8}", y[i, j]) + "</td>");
        }
        sb.AppendLine("</tr>");
    }
    sb.AppendLine("</table>");
    return sb.ToString();
}
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