Insertion right-to-left sort

! 4 sort, 136 pseudo random
program hello
    use My_module
    implicit none
    integer :: n, comparison, permutations, i
    real, allocatable :: array(:)
    real :: time_start, time_end
    write (0,'(40x,a)') '>>>INSERTION SORT<<<'
    !
    call cpu_time(time_start)
    !
    do i =1,13,1
        !write (0, fmt = '(a21$)') 'Enter size of array: '
        !read (*,fmt = *) n
        n = 2**i
        !
        allocate(array(n))
        !call random_array(n, array, 0.0, 100.0)
        call pseudo_random_array(n, array, 2.0, 8192.0)
        !call already_sorted(n, array, 2.0, 8192.0)
        !call WriteArray(n,array, 1, n, 0)
        call insertion_sort(n, array, comparison, permutations)
        !call WriteArray(n,array, 1, n, 0)
        write (0,fmt = '(/,a,i3)') 'Step number:', i
        write (0,fmt = '(a,i10,/,a,i10)') 'Comparison: ', comparison, 'Permutations', permutations
        deallocate(array)
        !
    end do
    !
    call cpu_time(time_end)
    write (0,fmt = '(/,a,f11.6)' ) 'Execution time: ',( time_end - time_start )
end program

module My_module
    implicit none
    contains
    !
    subroutine random_array(n, array, minimum, maximum)
        integer :: n, i
        real :: minimum, maximum, array(n), temp
        do i =1, n
            call random_number(temp)
            array(i) = minimum + (maximum-minimum)*temp
        end do
    end subroutine
    !
    subroutine pseudo_random_array(n, array, low, high)
        integer :: n, i
        real :: array(n), S, low, high
        real, parameter :: pi = 3.1415926535897932384626
        real :: fractional, x
        fractional(x) = x - real(int(x))
        !call cpu_time(S)
        S = 0.712345635224536436
        do i =1, n
            s = fractional( (s+pi)**5 )
            array(i) = low + (high - low)*s
        end do
    end subroutine
    !
    subroutine already_sorted(n, array, low, high)
        integer :: n, i
        real :: array(n), low, high
        do i =1, n
            array(i) = low + (high - low)*(n-i+1)/n
        end do
    end subroutine
    !
    subroutine ReadArray(n, array)
        integer :: i, n
        real, dimension(n) :: array
        do i =1,n
            write (*,fmt = '(/a, i2, a$)') 'Enter element number ', i, ': '
            read (*,*) array(i)
        end do
    end subroutine
    !
    subroutine WriteArray(n, array, first, last, spec)
        integer :: i, n, first, last, spec
        real, dimension(n) :: array
        character(len=31) :: cap = '+-----------+-----------------+'
        write (spec,'(a)') cap
        write (spec,'(a)') '|     i     |       a[i]      |'
        do i=first, last
            write (spec,'(a)') cap
            write (spec,'(a, i5, 3x, a, f15.7, 2x, a)') '|   ', i, '|', array(i), '|'
        end do
        write (spec,'(a/)') cap
    end subroutine
    !
    subroutine insertion_sort(n, array, comparison, permutations)
        integer :: n, i, k, comparison, permutations
        real :: array(n), temp
        comparison = 0
        permutations = 0
        if (n == 1) then
            return
        end if
        do i = (n-1),1,-1
            temp = array(i)
            k = i + 1
            do while (k <= n .and. array(k) < temp )
                comparison = comparison + 1
                array(k-1)=array(k)
                permutations = permutations + 1
                k = k + 1
            end do
            array(k-1) = temp
            comparison = comparison + 1
            !write (0,*) array
        end do
    end subroutine
end module