Tutorial: Matrix Structure

Tutorial: Using Matrix Structure

This tutorial explains how to use a Matrix structure for solving linear equations.

For the assignment, you must use the given Matrix structure and follow instructions for saving and modifying the data.

Preparation

Download

1. Download data files: NP_Matrix_TemplateCode_Data.zip

2. Download tutorial source files:

• TU_matrixTemplate_student.cpp

• myMatrix_student.h, myMatrix_student.cpp

Create Data Folder

Create a folder in C:\ Drive and name the folder as NP_Data

• C:\NP_Data

For each assignment, create the assignment folder and save the dataset.

Example: Assignment999

• **C:\NP_Data\Assignment999 **

For this tutorial, unzip the downloaded data files and copy them under the data folder Assignment999

NP_Matrix_Data_Example_img

Create Project

Create a new empty project in Visual Studio Community. Name the project as TU_MatrixTemplate

• e.g ) C:\Users\yourID\source\repos\NP\tutorial\TU_MatrixTemplate

Create a new C/C++ source file for main()

• Name the source file as TU_matrixTemplate.cpp

• Use the following source code : TU_matrixTemplate_student.cpp

Save the downloaded library header files in your \include\ folder :myMatrix_student.h, myMatrix_student.cpp

• Write your name in the comment section

• Re-name the header files as:

  • myMatrix.h, myMatrix.cpp

Create and Modify Dataset

For each assignment, create the assignment folder and save the dataset.

• Example: Assignment000

  • **C:\NP_Data\Assignment000 **

Use the text file and file name as instructed in each assignment.

You must use the same name of text files as instructed. Otherwise, it will not be graded

Example:

- Announcement for Assignment3 -

[File Path]
    C:/NP_Data/Assignment3

[File Name]
Q1.
    matrix A : prob1_matA
    vector b : prob1_vecb
Q2.
    matrix A : prob2_matA
    vector b : prob2_vecb
Q3.
    matrix A : prob3_matA
    vector b : prob3_vecb

Make Text File

file_explorer_img

Modifying Text File

• Change Row : Enter

• Change Column: Tap

Notice: Regardless of number length

Example :

For Matrix, type:

• 1 tab 3 tab -2 tab 4 enter .... 3 tab -1 tab 6 tab 2 ctrl+s (저장)

matrix_text_file_example

For Vector, type:

• -11 enter 6 enter -9 enter 15 ctrl+s (저장)

vector_text_file_example

Using Matrix Structure Library

Matrix structure library

Provided library: myMatrix.h

// myMatrix.h
typedef struct { 
	double** at;
	int rows, cols;
}Matrix;


// Create Matrix with specified size
extern	Matrix	createMat(int _rows, int _cols);

// Free a memory allocated matrix
extern	void	freeMat(Matrix _A);

// Create a matrix from a text file
extern	Matrix	txt2Mat(std::string _filePath, std::string _fileName);

//// Print matrix
extern	void	printMat(Matrix _A, const char* _name);

// Matrix addition
extern	Matrix	addMat(Matrix _A, Matrix _B);

// ....

Example Code

/*==========================================================================*/
/*					Variables declaration & initialization					*/
/*--------------------------------------------------------------------------*/
	// Option 1:  Read from datafile
	Matrix matA = txt2Mat(path, "prob1_matA");
	Matrix vecb = txt2Mat(path, "prob1_vecb");

	// Option 2:  Create an empty Matrix or Vector
	int rows = 4;
	int cols = 4;
	Matrix matC = createMat(rows, cols);
		
	// Option 3:  Create a zero matrix with specific size
	Matrix matD = zeros(matA.rows, matA.cols);


/*==========================================================================*/
/*					Accessing, modifying Matrix 							*/
/*--------------------------------------------------------------------------*/
	// Example:   Accessing each element in Matrix
	for (int i = 0; i < matA.rows; i++)
		for (int j = 0; j < matA.cols; j++)
			matC.at[i][j] = matA.at[i][j];
	printMat(matA, "matA");

	
	// Exmaple: Applying your NP algorithm
	Matrix matAdd = addMat(matA, matC);
	printMat(matAdd, "matU + matA");


/*==========================================================================*/
/*							  Deallocate memory 							*/
/*==========================================================================*/
	freeMat(matA);		freeMat(vecb);

What to change for Assignment

1. Initially, change the assignment number for #define ASGN

   • DO NOT modify other code lines

    #include "myMatrix.h"
    
    #define ASGN		999		// enter your assignment number
    #define EVAL		0		// [※ DO NOT EDIT !!!]
    
    
    int main(int argc, char* argv[])
    {
    	/*	 [※ DO NOT EDIT !!!]   Resources file path setting for evaluation	*/
    	std::string path = "C:/NP_Data/Assignment" + std::to_string(ASGN) + "/";
    
    #if EVAL
    	path += "eval/";
    #endif
    
        ...
    

2. Read data text files. You must use the given file names.

3. Then, apply your numerical programming algorithm.

/*==========================================================================*/
/*					Variables declaration & initialization					*/
/*--------------------------------------------------------------------------*/
/*   - You can change the variable names									*/
/*   - However, you must use the specified txt file name					*/	
/*==========================================================================*/
Matrix matA = txt2Mat(path, "prob1_matA");
Matrix vecb = txt2Mat(path, "prob1_vecb");
Matrix matU = txt2Mat(path, "prob1_matU");
Matrix vecd = txt2Mat(path, "prob1_vecd");
Matrix vecx_true = txt2Mat(path, "prob1_vecx_true");
// Your Code goes Here
// Your Code goes Here



/*==========================================================================*/
/*					Apply your numerical method algorithm					*/
/*==========================================================================*/
Matrix matAdd = addMat(matA, matU);		// example code
// Your Code goes Here
// Your Code goes Here  

//   ...

4. Prints vector or matrix results. You have to give a brief description for each print.

    
        /*==========================================================================*/
        /*                          Print your results                              */
        /*==========================================================================*/
        printMat(matA, "Problem 1, Matrix A");
        printMat(vecb, "Problem 1, Vector b");
    
    

5. Free memory allocated to a matrix.

   • Even if you omit the free process, the code will work. However, it can cause memory leaks.

        /*==========================================================================*/
        /*                          Deallocate memory                               */
        /*==========================================================================*/
        freeMat(matA);
        freeMat(vecb);
   
   

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Tutorial & Exercise

Declare and define the following functions in myMatrix.h and myMatrix.cpp

// initialization of Matrix elements
extern	void	initMat(Matrix _A, double _val);

// Create matrix of all zeros
extern	Matrix	zeros(int _rows, int _cols);

// Create matrix of all ones
extern	Matrix	ones(int _rows, int _cols);

// Multiply matrix A to B
extern	Matrix	multMat(Matrix _A, Matrix _B);

// Create identity 
extern	Matrix	eye(int _rows, int _cols);

// Create Transpose matrix
extern	Matrix	transpose(Matrix _A);

// Copy matrix
extern	Matrix	copyMat(Matrix _A);

// Copy matrix Elements from A to B
extern	void	copyVal(Matrix _A, Matrix _B);

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