Topic: Matrix Multiplication
Due: 11:59pm Tuesday, 2 October 2012

Please make sure you adhere to the policies on academic integrity.

Your task

In class, we gave an initial implementation of the matrix class that supported construction, indexing, and addition, as well as scalar multiplication. Your goal is to implement the function to support matrix multiplications. It has signature

  matrix operator*(const matrix& other) const

We are providing the basic framework for the matrix class, and a very simple driver named test that allows you to enter the name of a file that contains data for two matrices, separated by a blank line, and which reads those matrices and then tries to perform the appropriate additions and multiplications based upon the dimensions of those matrices.

Files we are providing

cp -R /Public/goldwasser/146/asgn03 .

• matrix.h
  This is the only file that you should edit. We will start you out with the version that we described during lecture. You will need to complete the implementation for matrix multiplication.
• matrixio.cpp
  This is some supporting code that we have written that provides reasonable I/O capabilities for the matrix class. In particular, it provides the functionality for printing a formatted matrix to an output stream, or reading data for a matrix from an input stream.
• test.cpp
  This is a simple driver allowing us to test the functionality of additions and multiplications.
• sample1.txt
  This is a sample of an input file for use with the test driver. The file format should consist of two matrices, separated by a blank line. This particular example gives two different 2x2 matrices. The test driver will compute the product A*B and B*A for those matrices, A and B. The product A*B should be the 2x2 result

   34.000  22.000
  126.000  82.000

  The product B*A is also a 2x2 matrix, with contents:

  52.000 72.000
  46.000 64.000

• sample2.txt
  Another sample file, this time with a 4x2 matrix A and a 2x4 matrix B. The produce of A*B should be the 2x2 result

  140.000 150.000
  348.000 374.000

  The product of B*A should be the 4x4 result

   65.000  86.000 107.000 128.000
   77.000 102.000 127.000 152.000
   89.000 118.000 147.000 176.000
  101.000 134.000 167.000 200.000

• makefile
  This is a makefile for the project. If you type the command

        make
        

  it will attempt to compile your matrix code and the test driver. Assuming it compiles cleanly, you can execute the driver by subsequently typing

        ./test
        

Submitting your project

Your assignment should be submitted electronically (details on the submission process). The only file that I need from you is the source code matrix.h.