C#实现矩阵加法、取负、数乘、乘法的方法

/// <summary>/// 判断一个二维数组是否为矩阵/// </summary>/// <param name="matrix">二维数组</param>/// <returns>true:是矩阵 false:不是矩阵</returns>private static bool isMatrix(double[][] matrix){ //空矩阵是矩阵 if (matrix.Length < 1) return true; //不同行列数如果不相等，则不是矩阵 int count = matrix[0].Length; for (int i = 1; i < matrix.Length; i++) {  if (matrix[i].Length != count)  {   return false;  } } //各行列数相等，则是矩阵 return true;}

/// <summary>/// 计算一个矩阵的行数和列数/// </summary>/// <param name="matrix">矩阵</param>/// <returns>数组：行数、列数</returns>private static int[] MatrixCR(double[][] matrix){ //接收到的参数不是矩阵则报异常 if (!isMatrix(matrix)) {  throw new Exception("接收到的参数不是矩阵"); } //空矩阵行数列数都为0 if (!isMatrix(matrix) || matrix.Length == 0) {  return new int[2] { 0, 0 }; } return new int[2] { matrix.Length, matrix[0].Length };}

/// <summary>/// 打印矩阵/// </summary>/// <param name="matrix">待打印矩阵</param>private static void PrintMatrix(double[][] matrix){ for (int i = 0; i < matrix.Length; i++) {  for (int j = 0; j < matrix[i].Length; j++)  {   Console.Write(matrix[i][j] + "/t");   //注意不能写为：Console.Write(matrix[i][j] + '/t');  }  Console.WriteLine(); }}

/// <summary>/// 矩阵加法/// </summary>/// <param name="matrix1">矩阵1</param>/// <param name="matrix2">矩阵2</param>/// <returns>和</returns>private static double[][] MatrixAdd(double[][] matrix1, double[][] matrix2){ //矩阵1和矩阵2须为同型矩阵 if (MatrixCR(matrix1)[0] != MatrixCR(matrix2)[0] ||  MatrixCR(matrix1)[1] != MatrixCR(matrix2)[1]) {  throw new Exception("不同型矩阵无法进行加法运算"); } //生成一个与matrix1同型的空矩阵 double[][] result = new double[matrix1.Length][]; for (int i = 0; i < result.Length; i++) {  result[i] = new double[matrix1[i].Length]; } //矩阵加法：把矩阵2各元素值加到矩阵1上，返回矩阵1 for (int i = 0; i < result.Length; i++) {  for (int j = 0; j < result[i].Length; j++)  {   result[i][j] = matrix1[i][j] + matrix2[i][j];  } } return result;}

/// <summary>/// 矩阵取负/// </summary>/// <param name="matrix">矩阵</param>/// <returns>负矩阵</returns>private static double[][] NegtMatrix(double[][] matrix){ //合法性检查 if (!isMatrix(matrix)) {  throw new Exception("传入的参数并不是一个矩阵"); } //参数为空矩阵则返回空矩阵 if (matrix.Length == 0) {  return new double[][] { }; } //生成一个与matrix同型的空矩阵 double[][] result = new double[matrix.Length][]; for (int i = 0; i < result.Length; i++) {  result[i] = new double[matrix[i].Length]; } //矩阵取负：各元素取相反数 for (int i = 0; i < result.Length; i++) {  for (int j = 0; j < result[0].Length; j++)  {   result[i][j] = -matrix[i][j];  } } return result;}

/// <summary>/// 矩阵数乘/// </summary>/// <param name="matrix">矩阵</param>/// <param name="num">常数</param>/// <returns>积</returns>private static double[][] MatrixMult(double[][] matrix, double num){ //合法性检查 if (!isMatrix(matrix)) {  throw new Exception("传入的参数并不是一个矩阵"); } //参数为空矩阵则返回空矩阵 if (matrix.Length == 0) {  return new double[][] { }; } //生成一个与matrix同型的空矩阵 double[][] result = new double[matrix.Length][]; for (int i = 0; i < result.Length; i++) {  result[i] = new double[matrix[i].Length]; } //矩阵数乘：用常数依次乘以矩阵各元素 for (int i = 0; i < result.Length; i++) {  for (int j = 0; j < result[0].Length; j++)  {   result[i][j] = matrix[i][j] * num;  } } return result;}

/// <summary>/// 矩阵乘法/// </summary>/// <param name="matrix1">矩阵1</param>/// <param name="matrix2">矩阵2</param>/// <returns>积</returns>private static double[][] MatrixMult(double[][] matrix1, double[][] matrix2){ //合法性检查 if (MatrixCR(matrix1)[1] != MatrixCR(matrix2)[0]) {  throw new Exception("matrix1 的列数与 matrix2 的行数不想等"); } //矩阵中没有元素的情况 if (matrix1.Length == 0 || matrix2.Length == 0) {  return new double[][] { }; } //matrix1是m*n矩阵，matrix2是n*p矩阵，则result是m*p矩阵 int m = matrix1.Length, n = matrix2.Length, p = matrix2[0].Length; double[][] result = new double[m][]; for (int i = 0; i < result.Length; i++) {  result[i] = new double[p]; } //矩阵乘法：c[i,j]=Sigma(k=1→n,a[i,k]*b[k,j]) for (int i = 0; i < m; i++) {  for (int j = 0; j < p; j++)  {   //对乘加法则   for (int k = 0; k < n; k++)   {    result[i][j] += (matrix1[i][k] * matrix2[k][j]);   }  } } return result;}

static void Main(string[] args){ //示例矩阵 double[][] matrix1 = new double[][]  {  new double[] { 1, 2, 3 },  new double[] { 4, 5, 6 },  new double[] { 7, 8, 9 } }; double[][] matrix2 = new double[][]  {  new double[] { 2, 3, 4 },  new double[] { 5, 6, 7 },  new double[] { 8, 9, 10 } }; //矩阵加法 PrintMatrix(MatrixAdd(matrix1, matrix2)); Console.WriteLine(); //矩阵取负 PrintMatrix(NegtMatrix(matrix1)); Console.WriteLine(); //矩阵数乘 PrintMatrix(MatrixMult(matrix1, 3)); Console.WriteLine(); //矩阵乘法 PrintMatrix(MatrixMult(  new double[][] {   new double[]{ 4, -1, 2 },   new double[]{ 1, 1, 0 },   new double[]{ 0, 3, 1 }},  new double[][] {   new double[]{ 1, 2 },   new double[]{ 0, 1 },   new double[]{ 3, 0 }})); Console.WriteLine(); Console.ReadLine();}