program matmulf90 ! Multiplikation von Matrizen use kinds implicit none integer, parameter :: n = 1000 real(kind=REAL8), dimension(n, n) :: a, b, c real(kind=REAL8) :: spur, spur1, cth integer :: i, j, k ! Anfangswerte setzen do i=1, n do j=1, n a(i,j) = i + j b(i,j) = i - j enddo b(i,i) = 1.0 enddo ! Matrixmultiplikation c = matmul(a, b) ! Testdaten ausgeben spur1 = n * (n+1) print *, "Spur theoretisch: ", spur1 spur = 0.0 do i = 1, n spur = spur + c(i,i) enddo print *, "Spur : ", spur cth = 333331003.0D0 print *, "c(1,2) theor. : ", cth print *, "c(1,2) : ", c(1,2) end program matmulf90