Question

Write a Fortran program that reads in two NxN matrices A & B, and prints their element-wise sum (A+B), element-wise difference (A-B), element-wise division (A/B), element-wise product (A*B), and their matrix product (matmul(A,B)), on the standard output.

Answer 1

Addition
program sum                                          !a: name of program
        !an example of program  structure                    !b: a  comment   
        real :: answer,x,y                                   !c: declarations
        print  *, 'Enter two numbers'                        !d: output
        read  *, x                                           !e: input
        read  *, y                                           !e: input
        answer=x+y                                           !f: arithmetic
        print  *, 'The total is ', answer                    !g: output
        end  program sum                                     !h: end of program

program matMulProduct

   integer, dimension(3,3) :: a, b, c
   integer :: i, j
    
   do i = 1, 3
      do j = 1, 3
         a(i, j) = i+j
      end do
   end do
   
   print *, 'Matrix Multiplication: A Matrix'
   
   do i = 1, 3
      do j = 1, 3
         print*, a(i, j)
      end do
   end do
   
   do i = 1, 3
      do j = 1, 3
         b(i, j) = i*j
      end do
   end do
   
   Print*, 'Matrix Multiplication: B Matrix'
   
   do i = 1, 3
      do j = 1, 3
         print*, b(i, j)
      end do
   end do
   
   c = matmul(a, b)
   Print*, 'Matrix Multiplication: Result Matrix'
   
   do i = 1, 3
      do j = 1, 3
         print*, c(i, j)
      end do
   end do
   
end program matMulProduct

Matrix Multiplication: A Matrix
2
3
4
3
4
5
4
5
6
 Matrix Multiplication: B Matrix
1
2
3
2
4
6
3
6
9
Matrix Multiplication: Result Matrix
20
40
60
26
52
78
32
64
96