Solved

multiplication and division for a 2x2 matrix

Posted on 2004-05-01
3
1,670 Views
Last Modified: 2008-02-01
#include <iostream>

using namespace std;

class Matrix {
     
public:
     Matrix(int val = 0) : nValue(val) { Initialise(); }
     ~Matrix() {};
     Matrix add(const Matrix& rhs);
     Matrix sub(const Matrix& rhs);
     Matrix mul(const Matrix& rhs);
     Matrix div(const Matrix& rhs);
     void print();
     void Initialise();
     void Clear();                        
private:
     int M[2][2];
     int nCols;
     int nRows;
     int size;
     int nValue;
};


void Matrix::Initialise()
{
     for (int r = 0; r < 2; r++) {
          for (int c = 0; c < 2; c++) {
               M[r][c] = nValue;
          }
     }
}

void Matrix::Clear()
{
     for (int r = 0; r < 2; r++) {
          for (int c = 0; c < 2; c++) {
               M[r][c] = 0;
          }
     }
}

Matrix Matrix::add(const Matrix& rhs)
{
     Matrix temp;

     for (int r = 0; r < 2; r++) {
          for (int c = 0; c < 2; c++) {
               temp.M[r][c] = rhs.M[r][c] + M[r][c];
          }
     }
     return temp;
}

Matrix Matrix::sub(const Matrix& rhs)
{
     Matrix temp;

     for (int r = 0; r < 2; r++) {
          for (int c = 0; c < 2; c++) {
               temp.M[r][c] = rhs.M[r][c] - M[r][c];
          }
     }
     return temp;
}

Matrix Matrix::mul(const Matrix& rhs)
{
     Matrix temp;

     for (int r = 0; r < 2; r++) {
          for (int c = 0; c < 2; c++) {
               temp.M[r][c] = rhs.M[r][c] * M[r][c];
          }
     }
     return temp;
}

Matrix Matrix::div(const Matrix& rhs)
{
     Matrix temp;

     for (int r = 0; r < 2; r++) {
          for (int c = 0; c < 2; c++) {
               temp.M[r][c] = rhs.M[r][c] / M[r][c];
          }
     }
     return temp;
}

void Matrix::print()
{
     for (int r = 0; r < 2; r++) {
          for (int c = 0; c < 2; c++) {
               cout << M[r][c] << "\t";
          }
          cout << endl;
     }
}


int main()
{
     Matrix a(2);
     Matrix b(3);
     Matrix c = a.add(b);
     c.print();

     Matrix d(2);
     Matrix e(3);
     Matrix f = a.sub(b);
     f.print();

     Matrix g(2);
     Matrix h(3);
     Matrix i = a.mul(b);
     i.print();

     Matrix j(2);
     Matrix k(3);
     Matrix l = a.div(b);
     l.print();
     
     return 0;

}

output:

5       5
5       5
1       1
1       1
6       6
6       6

How would you write the implementation for multiplication and division?  I have looked at some examples but cannot grasp the concept.  Please advise.
0
Comment
Question by:edelossantos
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
3 Comments
 
LVL 4

Assisted Solution

by:PerryDK
PerryDK earned 500 total points
ID: 10969766
Have a look at http://www.maths-help.co.uk/Knowldge/Alg/Matrices/Question.htm

Secondly I'm not real clear on your Martrix design.  Is this intended to be a class that can only handle 2x2 matricies?  Or is your Matrix class supposed to handle any r by c matrix?
0
 
LVL 4

Accepted Solution

by:
PerryDK earned 500 total points
ID: 10969777
Here is matrix multiplication for 2x2 matrix given the definition at http://www.maths-help.co.uk/Knowldge/Alg/Matrices/Question.htm

Matrix Matrix::mul(const Matrix& rhs)
{
  Matrix temp;

  for (int r = 0; r < 2; r++)
  {
    for (int c = 0; c < 2; c++)
    {
      temp.M[r][c] = 0;

      for(int x = 0; x < 2; x++
      {
        temp.M[r][c] += rhs.M[c][x] * M[x][c];
      }
    }
  }
  return temp;
}

For you Matrix division I'm not exactly sure what matrix division is unless you mean multiplying by the inverse of a matrix?
0
 
LVL 4

Assisted Solution

by:PerryDK
PerryDK earned 500 total points
ID: 10969781
temp.M[r][c] += rhs.M[c][x] * M[x][c];

Change this to

temp.M[r][c] += rhs.M[x][c] * M[c][x];
0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction This article is a continuation of the C/C++ Visual Studio Express debugger series. Part 1 provided a quick start guide in using the debugger. Part 2 focused on additional topics in breakpoints. As your assignments become a little more …
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
The goal of the tutorial is to teach the user how to use functions in C++. The video will cover how to define functions, how to call functions and how to create functions prototypes. Microsoft Visual C++ 2010 Express will be used as a text editor an…
The viewer will be introduced to the technique of using vectors in C++. The video will cover how to define a vector, store values in the vector and retrieve data from the values stored in the vector.

630 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question