PROGRAM mul
  USE naivmat
  USE bettmat
  USE dotmat
  IMPLICIT none

  integer, parameter :: seed = 123456
  real :: time
  integer :: dim = 10, multype = 1, realtype = 4

  DO WHILE (dim < 2000)

     SELECT CASE(realtype)
        CASE (4)
           time = measure_4(dim)
        ! CASE (8)
        !    time = measure_8(dim)
        ! CASE (16)
        !    time = measure_16(dim)
        CASE default
           write (*, *) "wrong kind for real: ", realtype

     END SELECT
        
     print '(I11," ",ES11.5)', dim, time

     dim = dim * 2
     
  END DO

CONTAINS

  SUBROUTINE init_random_seed()
    integer :: i, n
    
    call random_seed(size = n)
    
    call random_seed(put = (/ ((seed + i) * 37, i = 1, n) /))
    
  END SUBROUTINE init_random_seed
  

  real FUNCTION measure_4(dim) result(time)
    integer, intent(in) :: dim
    real(kind=4), dimension(:,:), allocatable :: mat1, mat2, res
    real :: start, end

    call init_random_seed()

    allocate(mat1(dim,dim))
    allocate(mat2(dim,dim))
    allocate(res(dim,dim))

    call random_number(mat1)
    call random_number(mat2)

    call cpu_time(start)

    SELECT CASE(multype)
       CASE (1)
          res = naivmull(mat1, mat2)
       CASE (2)
          res = bettmull(mat1, mat2)
       CASE (3)
          res = dotmull(mat1, mat2)
       CASE default
          res = matmul(mat1, mat2)
       
    END SELECT

    call cpu_time(end)
    
    time = end - start
    
  END FUNCTION measure_4
  
END PROGRAM mul