program test_mtprng
!---------------------------------------------------------------------
! From the Algorithmic Conjurings of Scott Robert Ladd comes...
!---------------------------------------------------------------------
!
!  test_mtprng.f90
!
!  A program for testing the mtprng (Mersenne Twister) module.
!
!---------------------------------------------------------------------
!
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!
!  This notice applies *only* to this specific expression of this
!  algorithm, and does not imply ownership or invention of the
!  implemented algorithm.
!  
!  If you modify this file, you may insert additional notices
!  immediately following this sentence.
!  
!  Copyright 2001, 2002, 2004 Scott Robert Ladd.
!  All rights reserved, except as noted herein.
!
!  This computer program source file is supplied "AS IS". Scott Robert
!  Ladd (hereinafter referred to as "Author") disclaims all warranties,
!  expressed or implied, including, without limitation, the warranties
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!  assumes no liability for direct, indirect, incidental, special,
!  exemplary, or consequential damages, which may result from the use
!  of this software, even if advised of the possibility of such damage.
!  
!  The Author hereby grants anyone permission to use, copy, modify, and
!  distribute this source code, or portions hereof, for any purpose,
!  without fee, subject to the following restrictions:
!  
!      1. The origin of this source code must not be misrepresented.
!  
!      2. Altered versions must be plainly marked as such and must not
!         be misrepresented as being the original source.
!  
!      3. This Copyright notice may not be removed or altered from any
!         source or altered source distribution.
!  
!  The Author specifically permits (without fee) and encourages the use
!  of this source code for entertainment, education, or decoration. If
!  you use this source code in a product, acknowledgment is not required
!  but would be appreciated.
!  
!  Acknowledgement:
!      This license is based on the wonderful simple license that
!      accompanies libpng.
!
!-----------------------------------------------------------------------
!
!  For more information on this software package, please visit
!  Scott's web site, Coyote Gulch Productions, at:
!
!      http://www.coyotegulch.com
!  
!-----------------------------------------------------------------------

    use stdtypes
    use mtprng
    implicit none

    integer, parameter :: TEST_SIZE = 2000000000
    integer(INT64) x64, max64, min64
    integer :: i, j, count, count_rate, count_max, x, total
    real(IEEE64) :: n, l, s
    integer, dimension(10) :: counts
    character(*), parameter :: fmt1 = "(A,F30.27)"
    type(mtprng_state) :: state

    !call system_clock(count,count_rate,count_max)
    call mtprng_init(1,state)

    min64 = HUGE(INT32)
    max64 = -min64
    
    do i = 1, TEST_SIZE
        x64 = mtprng_rand64(state)
        if (x64 < min64) min64 = x64
        if (x64 > max64) max64 = x64
    end do
    
    write(*,*) 'min 64 = ', min64
    write(*,*) 'max 64 = ', max64

    ! each real function
    write(*,*)
    write(*,*) 'mtprng_rand_real1 - interval [0,1]'

    s = huge(IEEE64)    
    l = -s
    do i = 1, TEST_SIZE
        n = mtprng_rand_real1(state)

        if (n < s) s = n
        if (n > l) l = n
    end do

    write(*,fmt1) "   largest = ", l
    write(*,fmt1) "  smallest = ", s

    ! each real function
    write(*,*)
    write(*,*) 'mtprng_rand_real2 - interval [0,1)'
    
    s = huge(IEEE64)    
    l = -s
    do i = 1, TEST_SIZE
        n = mtprng_rand_real2(state)

        if (n < s) s = n
        if (n > l) l = n
    end do

    write(*,fmt1) "   largest = ", l
    write(*,fmt1) "  smallest = ", s

    ! each real function
    write(*,*)
    write(*,*) 'mtprng_rand_real3 - interval (0,1)'
    
    s = huge(IEEE64)    
    l = -s
    do i = 1, TEST_SIZE
        n = mtprng_rand_real3(state)

        if (n < s) s = n
        if (n > l) l = n
    end do

    write(*,fmt1) "   largest = ", l
    write(*,fmt1) "  smallest = ", s

    ! check ranges
    counts = 0

    do i = 1, TEST_SIZE
        x = mtprng_rand_range(state,1,size(counts))
        counts(x) = counts(x) + 1
    end do

    write (*,*) " "

    total = 0

    do i = 1, size(counts)
        write(*,*) "counts ", i, " = ", counts(i)
        total = total + counts(i)
    end do

    write (*,*) "total = ", total

end program test_mtprng