program sample3
use omp_lib

        implicit real(8)(a-h,o-z)
        parameter (n=4096)
        real(8) a(n,n),c(n,n)
        real(4) b(n,n)
        real*8 t1, t2
        a=0.0d0
        call random_number(b)
        call random_number(c)
        write(6,50) 'Matrix Size = ', n
    50 format(1x,a,i5)
        t1 = omp_get_wtime()
        !$OMP parallel do 
        do j=1,n
            do k=1,n
                do i=1,n
                    a(i,j)=a(i,j)+b(i,k)*c(k,j)
                end do
            end do
        end do
        t2 = omp_get_wtime()
        !$OMP end parallel do
        write(6,60) 'Execution Time = ', t2-t1, ' sec','A(n,n) = ',a(n,n)
    60 format(1x,a,f10.3,a,1x,a,d24.15)
        stop
end