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CS561 Project 6

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1. Project Description

Write a Fortran 90 function MatrixInvert() and its interface definition that computes the inverse of a NxN matrix
• The function MatrixInvert(A) is called with 1 parameter:
  • A: an NxN matrix - N is a variable and your function must work for any size matrix (use Fortran 90's SIZE() function to figure out the size of the matrix)

  • The MatrixInvert(A) returns a NxN matrix that has the same size as the input matrix

I have written a Fortran 90 main program that reads in a matrix from an input file and calls MatrixInvert() to invert the matrix:

 PROGRAM Main

  IMPLICIT NONE

  integer i, j, N
  REAL, DIMENSION(:, :), ALLOCATABLE :: A, B

  INTERFACE
   SUBROUTINE Print( A )
     REAL, DIMENSION(:,:) :: A
   END SUBROUTINE
  END INTERFACE

  INCLUDE 'pj6interface.h'    !! You must provide this file

  READ *, N             !! Read size of matrix

  ALLOCATE(A(N, N))     !! Allocate source
  ALLOCATE(B(N, N))     !! Allocate destination

  DO i = 1, N
    READ *, A(i,:)      !! Read in input matrix
  END DO

  CALL Print( A )       !! Print input matrix

  B = MatrixInvert(A)   !! You must write this function (in another file)

  print *, "The inverse matrix is:"
  CALL Print( B )       !! Print result

  END

The main program includes a file named pj6interface.h which must contain an interface that describe the function MatrixInvert You must define the interface and store the definition in the file pj6interface.h (please do NOT change the pj6.f90 file that you must download for this project) Without this interface, the program will not compile.

In addition to the pj6interface.h file, you must write the function MatrixInvert and put that in another file - this file must have an extension ".f90" to be compiled by the Fortran compiler.

You can obtain the main program pj6.f90 for this project through this link: click here

Save a copy in your cs561 project directory.

2. Makefile

• You must provide a working Makefile that build your project

• The program name is main - that's the target name that you must use in your Makefile.

3. Testing the program

After you compiled the program successfully, obtain the following input data file for pj6: click here

Run the program with the following command:

   main < pj6.data

Your program should invert the matrix

	3  2  5  9
	1  7  3  7
	0 -9  1  8
	9  8  3  1

The structure of the input file is

	N
	a11  a12 .... a1N
	a21  a22 .... a2N
	...
	aN1  aN2 .... aNN

Try with other matrices to test your project thoroughly.

4. Turn in

• Turn in the "Makefile" file using the command:

       /home/cs561000/turnin Makefile pj6
  

• Turn in the INCLUDE file that contains the function interface for the MatrixInvert function using the command:

       /home/cs561000/turnin pj6interface.h  pj6a
  

• Turn in the file with the MatrixInvert function using the command:

       /home/cs561000/turnin yourFileName.f90 pj6b