C# 矩阵运算

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 矩阵运算
{
    class Program
    {
        static void Main(string[] args)
        {
            double[][] a = 
            {
                new double[]{1.0,2.0,3.0},
                new double[]{4.0,5.0,6.0},
                new double[]{7.0,8.0,9.0}
            };

            double[][] b = 
            {
                new double[]{2.0,-2.0,1.0},
                new double[]{1.0,3.0,9.0},
                new double[]{17.0,-3.0,7.0}
            };

            double[][] c =
            {
                new double[3],
                new double[3],
                new double[3]
            };

            Console.WriteLine("相乘结果:");
            MatrixMul(a, b, c);
            MatrixLog(c);
            Console.WriteLine("相加结果:");
            MatrixPlus(a, b, c);
            MatrixLog(c);
            Console.WriteLine("相减结果:");
            MatrixSub(a, b, c);
            MatrixLog(c);
            Console.ReadLine();
        }



        //矩阵相加
        public static void MatrixPlus(double[][] a, double[][] b, double[][] c) 
        {
            if (a == null || b == null || (a.Length != b.Length) || (a[0].Length != b[0].Length))
                return;

            for (int i = 0; i < a.Length; i++)
            {
                for (int k = 0; k < a[0].Length; k++) 
                {
                    c[i][k] = a[i][k] + b[i][k];
                }
            }
        }

        //矩阵相减
        public static void MatrixSub(double[][] a, double[][] b, double[][] c)
        {
            if (a == null || b == null || (a.Length != b.Length) || (a[0].Length != b[0].Length))
                return;

            for (int i = 0; i < a.Length; i++)
            {
                for (int k = 0; k < a[0].Length; k++)
                {
                    c[i][k] = a[i][k] - b[i][k];
                }
            }
        }

        //矩阵乘法
        public static void MatrixMul(double[][] a, double[][] b,double[][] c) 
        {
            if (a == null || b == null || a[0].Length != b.Length)
                return;

            for (int i = 0; i < a.Length; i++)
            {
                for (int k = 0; k < b[0].Length; k++)
                {
                    c[i][k] = 0;
                    for (int l = 0; l < a[0].Length; l++)
                    {
                        c[i][k] += (a[i][l] * b[l][k]);             //a矩阵i行所有元素 *  b矩阵j行所有元素之和 = 新的矩阵一个元素
                    }
                }   
            }
        }


        public static void MatrixLog(double[][] c) 
        {
            for (int i = 0; i < c.Length; i++)
            {
                for (int k = 0; k < c[i].Length; k++)
                {
                    Console.Write(c[i][k] + " ");
                }

                Console.WriteLine();
            }
        }

    }
}