Array Util (C#)

Here collects the C# implementation of Array utility functions for group research.

Array Multiply

Parameters: 2-d array * 2-d array

Return: 2-d array

		*Multiply 2-d arrays 
		*Param
		*/
		public static double[,] ArrayMul(double[,] a, double[,] b){
			if(a.GetLength(1)!=b.GetLength(0)){
				WriteLine("Row number in a is NOT equal to column number in b!");
				return null;
			}
			double[,] result = new double[a.GetLength(0),b.GetLength(1)];
			for(int i=0;i<a.GetLength(0);i++) {
				for(int j=0;j<b.GetLength(1);j++){
					double c = 0;
					for(int k=0;k<a.GetLength(1);k++){
						c+=a[i,k]*b[k,j];
					}
					result[i,j]=c;
				}
			}
			return result;
		}

Attention:

1. To use GetLength() for the length of different dimension.

2. To use [,] for 2-d array definition.

Array Initialization

Parameters: 2-d array

Return: void

		/***
		*Initialize 2-d array with random doubles (with given max)
		*/
		public static void ArrayInit(ref double[,] a, double max){
			Random rd = new Random();
			for(int i=0; i<a.GetLength(0); i++){
				for(int j=0; j<a.GetLength(1); j++){
					a[i,j] = rd.Next((int)max)+rd.NextDouble();
				}
			}
		}

Attention:

1. Random is defined under the namespace System, so please add `using System;'.

2. NextDouble() returns a double value (0,1), so if you need the integer part of a random value, refer to Next().

Array Presentation

Parameters: 2-d array

Return: void

		/***
		*Print out the entries in the given 2-d array.
		*/
		public static void ArrayPres(double[,] a){
			for(int i=0;i<a.GetLength(0);i++){
            	for(int j = 0; j<a.GetLength(1); j++){
            		Write($"{a[i,j]} ");
            	}
            	WriteLine();
            }
		}