LCOV - code coverage report
Current view: top level - src/common - parallel_rng_types.F (source / functions) Hit Total Coverage
Test: CP2K Regtests (git:262480d) Lines: 370 410 90.2 %
Date: 2024-11-22 07:00:40 Functions: 24 28 85.7 %

          Line data    Source code
       1             : !--------------------------------------------------------------------------------------------------!
       2             : !   CP2K: A general program to perform molecular dynamics simulations                              !
       3             : !   Copyright 2000-2024 CP2K developers group <https://cp2k.org>                                   !
       4             : !                                                                                                  !
       5             : !   SPDX-License-Identifier: GPL-2.0-or-later                                                      !
       6             : !--------------------------------------------------------------------------------------------------!
       7             : 
       8             : ! **************************************************************************************************
       9             : !> \brief Parallel (pseudo)random number generator (RNG) for multiple streams
      10             : !>      and substreams of random numbers.
      11             : !>
      12             : !>      In detail, this RNG provides 2**64 random number streams each with a
      13             : !>      length of 2**127 resulting in a length of 2**191 for the total RNG.
      14             : !>      Moreover, each stream is divided in 2**51 substream of length 2**76.
      15             : !>      The stream lengths refer to the default precision of 32 bit random
      16             : !>      number, but also an extended precision of 53 bit per random number
      17             : !>      can be requested. In this case, two 32 bit random numbers are used
      18             : !>      to generate a 53 bit random number and therefore the stream length
      19             : !>      is halved when extended precision are requested.
      20             : !>
      21             : !>      Usage hint:
      22             : !>
      23             : !>      type(rng_stream_type) :: rng_stream
      24             : !>      rng_stream = rng_stream_type(name, ..., error=error)
      25             : !>
      26             : !>      to generate the first stream. Optionally, you may define a different
      27             : !>      seed or create a stream of extended precision (53 bits). Then
      28             : !>
      29             : !>      type(rng_stream_type) :: next_rng_stream
      30             : !>      next_rng_stream = rng_stream_type(name, last_rng_stream=rng_stream)
      31             : !>
      32             : !>      to create all the following RNG streams w.r.t. the previous stream.
      33             : !>      The command line
      34             : !>
      35             : !>      x = rng_stream%next(error=error)
      36             : !>
      37             : !>      will provide the next real random number x between 0 and 1 and
      38             : !>
      39             : !>      ix = rng_stream%next(low, high, error=error)
      40             : !>
      41             : !>      the next integer random number ix between low and high from stream
      42             : !>      rng_stream. The default distribution type is a uniform distribution
      43             : !>      [0,1], but also other distribution types are available (see below).
      44             : !>
      45             : !> \par Literature
      46             : !>      P. L'Ecuyer, R. Simard, E. J. Chen, and W. D. Kelton,
      47             : !>      "An object-oriented random-number package with many long streams
      48             : !>       and substreams", Operations Research 50(6), 1073-1075 (2002)
      49             : !> \author C++ code converted to Fortran 90/95 (18.05.2005, Matthias Krack)
      50             : ! **************************************************************************************************
      51             : MODULE parallel_rng_types
      52             : 
      53             :    USE kinds,                           ONLY: default_string_length,&
      54             :                                               dp
      55             :    USE string_utilities,                ONLY: compress
      56             : #include "../base/base_uses.f90"
      57             : 
      58             :    IMPLICIT NONE
      59             : 
      60             :    PRIVATE
      61             : 
      62             :    ! Global parameters in this module
      63             : 
      64             :    CHARACTER(LEN=*), PARAMETER, PRIVATE :: rng_record_format = "(A40,I2,3L2,ES25.16,18F20.1)"
      65             :    INTEGER, PARAMETER                   :: rng_record_length = 433
      66             :    INTEGER, PARAMETER                   :: rng_name_length = 40
      67             : 
      68             :    ! Distribution types:
      69             : 
      70             :    ! GAUSSIAN: Gaussian distribution with zero mean and unit variance
      71             :    ! UNIFORM:  Uniform distribution [0,1] with 1/2 mean (default)
      72             : 
      73             :    INTEGER, PARAMETER       :: GAUSSIAN = 1, &
      74             :                                UNIFORM = 2
      75             : 
      76             :    REAL(KIND=dp), PARAMETER :: norm = 2.328306549295727688e-10_dp, &
      77             :                                m1 = 4294967087.0_dp, &
      78             :                                m2 = 4294944443.0_dp, &
      79             :                                a12 = 1403580.0_dp, &
      80             :                                a13n = 810728.0_dp, &
      81             :                                a21 = 527612.0_dp, &
      82             :                                a23n = 1370589.0_dp, &
      83             :                                two17 = 131072.0_dp, & ! 2**17
      84             :                                two53 = 9007199254740992.0_dp, & ! 2**53
      85             :                                fact = 5.9604644775390625e-8_dp ! 1/2**24
      86             : 
      87             :    !&<
      88             :    ! The following are the transition matrices of the two MRG components
      89             :    ! (in matrix form), raised to the powers 1, 2**76, 2**127, and -1
      90             : 
      91             :    ! Transition matrix for the first component raised to the power 2**0
      92             :    REAL(KIND=dp), DIMENSION(3, 3), PARAMETER :: a1p0 = RESHAPE([ &
      93             :          0.0_dp, 0.0_dp, -810728.0_dp, &
      94             :          1.0_dp, 0.0_dp, 1403580.0_dp, &
      95             :          0.0_dp, 1.0_dp,       0.0_dp &
      96             :          ], [3,3])
      97             : 
      98             :    ! Transition matrix for the second component raised to the power 2**0
      99             :    REAL(KIND=dp), DIMENSION(3, 3), PARAMETER :: a2p0 = RESHAPE([ &
     100             :          0.0_dp, 0.0_dp, -1370589.0_dp, &
     101             :          1.0_dp, 0.0_dp,        0.0_dp, &
     102             :          0.0_dp, 1.0_dp,   527612.0_dp &
     103             :          ], [3,3])
     104             : 
     105             :    ! Transition matrix for the first component raised to the power 2**76
     106             :    REAL(KIND=dp), DIMENSION(3, 3), PARAMETER :: a1p76 = RESHAPE([ &
     107             :            82758667.0_dp, 3672831523.0_dp, 3672091415.0_dp, &
     108             :          1871391091.0_dp,   69195019.0_dp, 3528743235.0_dp, &
     109             :          4127413238.0_dp, 1871391091.0_dp,   69195019.0_dp &
     110             :          ], [3,3])
     111             : 
     112             :    ! Transition matrix for the second component raised to the power 2**76
     113             :    REAL(KIND=dp), DIMENSION(3, 3), PARAMETER :: a2p76 = RESHAPE([ &
     114             :          1511326704.0_dp, 4292754251.0_dp, 3859662829.0_dp, &
     115             :          3759209742.0_dp, 1511326704.0_dp, 4292754251.0_dp, &
     116             :          1610795712.0_dp, 3889917532.0_dp, 3708466080.0_dp &
     117             :          ], [3,3])
     118             : 
     119             :    ! Transition matrix for the first component raised to the power 2**127
     120             :    REAL(KIND=dp), DIMENSION(3, 3), PARAMETER :: a1p127 = RESHAPE([ &
     121             :          2427906178.0_dp,  226153695.0_dp, 1988835001.0_dp, &
     122             :          3580155704.0_dp, 1230515664.0_dp,  986791581.0_dp, &
     123             :           949770784.0_dp, 3580155704.0_dp, 1230515664.0_dp &
     124             :          ], [3,3])
     125             : 
     126             :    ! Transition matrix for the second component raised to the power 2**127
     127             :    REAL(KIND=dp), DIMENSION(3, 3), PARAMETER :: a2p127 = RESHAPE([ &
     128             :          1464411153.0_dp,   32183930.0_dp, 2824425944.0_dp, &
     129             :           277697599.0_dp, 1464411153.0_dp,   32183930.0_dp, &
     130             :          1610723613.0_dp, 1022607788.0_dp, 2093834863.0_dp &
     131             :          ], [3,3])
     132             : 
     133             :    ! Inverse of a1p0
     134             :    REAL(KIND=dp), DIMENSION(3, 3), PARAMETER :: inv_a1 = RESHAPE([ &
     135             :           184888585.0_dp, 1.0_dp, 0.0_dp, &
     136             :                   0.0_dp, 0.0_dp, 1.0_dp, &
     137             :          1945170933.0_dp, 0.0_dp, 0.0_dp &
     138             :          ], [3,3])
     139             : 
     140             :    ! Inverse of a2p0
     141             :    REAL(KIND=dp), DIMENSION(3, 3), PARAMETER :: inv_a2 = RESHAPE([ &
     142             :                   0.0_dp, 1.0_dp, 0.0_dp, &
     143             :           360363334.0_dp, 0.0_dp, 1.0_dp, &
     144             :          4225571728.0_dp, 0.0_dp, 0.0_dp &
     145             :          ], [3,3])
     146             :    !&>
     147             : 
     148             :    ! Data type definitions
     149             : 
     150             :    ! Information on a stream. The arrays bg, cg, and ig contain the current
     151             :    ! state of the stream, the starting state of the current substream, and the
     152             :    ! starting state of the stream. This stream generates antithetic variates
     153             :    ! if antithetic = .TRUE.. It also generates numbers with extended precision
     154             :    ! (53 bits, if machine follows IEEE 754 standard), if extended_precision =
     155             :    ! .TRUE., otherwise, numbers with 32 bits precision are generated.
     156             : 
     157             :    TYPE rng_stream_type
     158             :       PRIVATE
     159             :       ! the name could be an allocatable, but gfortran (even with 9.1) does not properly implement
     160             :       ! automatic deallocation of it and a `final`routine which would do it triggers an ICE in 7.4.1
     161             :       CHARACTER(LEN=rng_name_length) :: name = ""
     162             :       INTEGER                        :: distribution_type = UNIFORM
     163             :       ! ig: initial state, cg: current state, bg: initial state of the substream
     164             :       REAL(KIND=dp), DIMENSION(3, 2) :: bg = 0.0_dp, cg = 0.0_dp, ig = 0.0_dp
     165             :       LOGICAL                        :: antithetic = .FALSE., extended_precision = .FALSE.
     166             :       ! only used for distribution type GAUSSIAN
     167             :       REAL(KIND=dp)                  :: buffer = 0.0_dp
     168             :       LOGICAL                        :: buffer_filled = .FALSE.
     169             : 
     170             :    CONTAINS
     171             :       PROCEDURE, PASS(self) :: fill_1
     172             :       PROCEDURE, PASS(self) :: fill_2
     173             :       PROCEDURE, PASS(self) :: fill_3
     174             :       GENERIC, PUBLIC :: fill => fill_1, fill_2, fill_3
     175             : 
     176             :       PROCEDURE, PASS(self) :: next_int
     177             :       PROCEDURE, PASS(self) :: next_real
     178             :       GENERIC, PUBLIC :: next => next_int, next_real
     179             : 
     180             :       PROCEDURE, PASS(self), PUBLIC :: dump
     181             :       PROCEDURE, PASS(self), PUBLIC :: write
     182             :       PROCEDURE, PASS(self), PUBLIC :: advance
     183             :       PROCEDURE, PASS(self), PUBLIC :: set
     184             :       PROCEDURE, PASS(self), PUBLIC :: get
     185             :       PROCEDURE, PASS(self), PUBLIC :: reset
     186             :       PROCEDURE, PASS(self), PUBLIC :: reset_to_substream
     187             :       PROCEDURE, PASS(self), PUBLIC :: reset_to_next_substream
     188             :       PROCEDURE, PASS(self), PUBLIC :: shuffle
     189             :    END TYPE rng_stream_type
     190             : 
     191             :    INTERFACE rng_stream_type
     192             :       MODULE PROCEDURE :: rng_stream_constructor
     193             :    END INTERFACE
     194             : 
     195             :    TYPE rng_stream_p_type
     196             :       TYPE(rng_stream_type), POINTER :: stream => NULL()
     197             :    END TYPE rng_stream_p_type
     198             : 
     199             :    ! Public parameters
     200             : 
     201             :    PUBLIC :: rng_record_length, &
     202             :              rng_name_length, &
     203             :              GAUSSIAN, &
     204             :              UNIFORM
     205             : 
     206             :    ! Public data types
     207             : 
     208             :    PUBLIC :: rng_stream_p_type, &
     209             :              rng_stream_type
     210             : 
     211             :    ! Public subroutines
     212             : 
     213             :    PUBLIC :: check_rng, &
     214             :              next_rng_seed, &
     215             :              write_rng_matrices, &
     216             :              rng_stream_type_from_record
     217             : 
     218             : CONTAINS
     219             : 
     220             : ! **************************************************************************************************
     221             : !> \brief Advance the state by n steps, i.e. jump n steps forward, if n > 0, or backward if n < 0.
     222             : !> \param self ...
     223             : !> \param e IF e > 0, let n = 2**e + c, IF e < 0, let n = -2**(-e) + c, IF e = 0, let n = c
     224             : !> \param c ...
     225             : !> \note The use of this method is discouraged
     226             : ! **************************************************************************************************
     227         112 :    SUBROUTINE advance(self, e, c)
     228             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     229             :       INTEGER, INTENT(IN)                                :: e, c
     230             : 
     231             :       REAL(KIND=dp), DIMENSION(3, 2)                     :: x
     232             :       REAL(KIND=dp), DIMENSION(3, 3)                     :: u1, u2, v1, v2, w1, w2
     233             : 
     234         112 :       u1 = 0.0_dp
     235         112 :       u2 = 0.0_dp
     236         112 :       v1 = 0.0_dp
     237         112 :       v2 = 0.0_dp
     238         112 :       w1 = 0.0_dp
     239         112 :       w2 = 0.0_dp
     240             : 
     241         112 :       IF (e > 0) THEN
     242           4 :          CALL mat_two_pow_mod_m(a1p0, u1, m1, e)
     243           4 :          CALL mat_two_pow_mod_m(a2p0, u2, m2, e)
     244         108 :       ELSE IF (e < 0) THEN
     245           3 :          CALL mat_two_pow_mod_m(inv_a1, u1, m1, -e)
     246           3 :          CALL mat_two_pow_mod_m(inv_a2, u2, m2, -e)
     247             :       END IF
     248             : 
     249         112 :       IF (c >= 0) THEN
     250         112 :          CALL mat_pow_mod_m(a1p0, v1, m1, c)
     251         112 :          CALL mat_pow_mod_m(a2p0, v2, m2, c)
     252             :       ELSE
     253           0 :          CALL mat_pow_mod_m(inv_a1, v1, m1, -c)
     254           0 :          CALL mat_pow_mod_m(inv_a2, v2, m2, -c)
     255             :       END IF
     256             : 
     257         112 :       IF (e == 0) THEN
     258         105 :          w1 = v1
     259         105 :          w2 = v2
     260             :       ELSE
     261           7 :          CALL mat_mat_mod_m(u1, v1, w1, m1)
     262           7 :          CALL mat_mat_mod_m(u2, v2, w2, m2)
     263             :       END IF
     264             : 
     265         112 :       x = 0.0_dp
     266             : 
     267         112 :       CALL mat_vec_mod_m(w1, self%cg(:, 1), x(:, 1), m1)
     268         112 :       CALL mat_vec_mod_m(w2, self%cg(:, 2), x(:, 2), m2)
     269             : 
     270        1008 :       self%cg = x
     271         112 :    END SUBROUTINE advance
     272             : 
     273             : ! **************************************************************************************************
     274             : !> \brief ...
     275             : !> \param output_unit ...
     276             : !> \param ionode ...
     277             : ! **************************************************************************************************
     278           3 :    SUBROUTINE check_rng(output_unit, ionode)
     279             : 
     280             :       ! Check the parallel (pseudo)random number generator (RNG).
     281             : 
     282             :       INTEGER, INTENT(IN)                                :: output_unit
     283             :       LOGICAL, INTENT(IN)                                :: ionode
     284             : 
     285             :       INTEGER                                            :: i, sumi
     286             :       REAL(KIND=dp)                                      :: sum, sum3
     287             :       REAL(KIND=dp), DIMENSION(3, 2)                     :: germe
     288             :       TYPE(rng_stream_type)                              :: cantor, g1, g2, g3, galois, laplace, &
     289             :                                                             poisson
     290             : 
     291             :       ! -------------------------------------------------------------------------
     292             :       ! Test 1
     293             : 
     294             :       ! Create RNG test streams
     295             : 
     296           3 :       g1 = rng_stream_type("g1")
     297           3 :       g2 = rng_stream_type("g2", g1)
     298           3 :       g3 = rng_stream_type("g3", g2)
     299             : 
     300           3 :       IF (ionode) THEN
     301             :          WRITE (UNIT=output_unit, FMT="(/,T2,A)") &
     302           2 :             "RESULTS OF THE PSEUDO(RANDOM) NUMBER GENERATOR TEST RUNS", &
     303           4 :             "Initial states of the (pseudo)random number streams (test 1):"
     304           2 :          CALL g1%write(output_unit)
     305           2 :          CALL g2%write(output_unit)
     306           2 :          CALL g3%write(output_unit)
     307             :       END IF
     308             : 
     309           3 :       sum = g2%next() + g3%next()
     310             : 
     311           3 :       CALL g1%advance(5, 3)
     312           3 :       sum = sum + g1%next()
     313             : 
     314           3 :       CALL g1%reset()
     315         108 :       DO i = 1, 35
     316         108 :          CALL g1%advance(0, 1)
     317             :       END DO
     318           3 :       sum = sum + g1%next()
     319             : 
     320           3 :       CALL g1%reset()
     321             : 
     322           3 :       sumi = 0
     323         108 :       DO i = 1, 35
     324         108 :          sumi = sumi + g1%next(1, 10)
     325             :       END DO
     326           3 :       sum = sum + sumi/100.0_dp
     327             : 
     328           3 :       sum3 = 0.0_dp
     329         303 :       DO i = 1, 100
     330         303 :          sum3 = sum3 + g3%next()
     331             :       END DO
     332           3 :       sum = sum + sum3/10.0_dp
     333             : 
     334           3 :       CALL g3%reset()
     335          18 :       DO i = 1, 5
     336          18 :          sum = sum + g3%next()
     337             :       END DO
     338             : 
     339           3 :       CALL g3%reset()
     340          15 :       DO i = 1, 4
     341          15 :          CALL g3%reset_to_next_substream()
     342             :       END DO
     343          18 :       DO i = 1, 5
     344          18 :          sum = sum + g3%next()
     345             :       END DO
     346             : 
     347           3 :       CALL g3%reset_to_substream()
     348          18 :       DO i = 1, 5
     349          18 :          sum = sum + g3%next()
     350             :       END DO
     351             : 
     352           3 :       CALL g2%reset_to_next_substream()
     353           3 :       sum3 = 0.0_dp
     354      300003 :       DO i = 1, 100000
     355      300003 :          sum3 = sum3 + g2%next()
     356             :       END DO
     357           3 :       sum = sum + sum3/10000.0_dp
     358             : 
     359           3 :       CALL g3%set(antithetic=.TRUE.)
     360           3 :       sum3 = 0.0_dp
     361      300003 :       DO i = 1, 100000
     362      300003 :          sum3 = sum3 + g3%next()
     363             :       END DO
     364           3 :       sum = sum + sum3/10000.0_dp
     365             : 
     366           3 :       IF (ionode) THEN
     367             :          WRITE (UNIT=output_unit, FMT="(/,T2,A)") &
     368           2 :             "Final states of the (pseudo)random number streams (test 1):"
     369           2 :          CALL g1%write(output_unit)
     370           2 :          CALL g2%write(output_unit)
     371           2 :          CALL g3%write(output_unit)
     372             :          WRITE (UNIT=output_unit, FMT="(/,(T2,A))") &
     373           2 :             "This test routine should print for test 1 the number 25.342059"
     374             :          WRITE (UNIT=output_unit, FMT="(T2,A,F10.6)") &
     375           2 :             "The actual result of test 1 is                      ", sum
     376             :       END IF
     377             : 
     378             :       ! -------------------------------------------------------------------------
     379             :       ! Test 2
     380             : 
     381          27 :       germe(:, :) = 1
     382             : 
     383           3 :       poisson = rng_stream_type("Poisson", seed=germe)
     384           3 :       laplace = rng_stream_type("Laplace", poisson)
     385           3 :       galois = rng_stream_type("Galois", laplace)
     386           3 :       cantor = rng_stream_type("Cantor", galois)
     387             : 
     388           3 :       IF (ionode) THEN
     389             :          WRITE (UNIT=output_unit, FMT="(/,T2,A)") &
     390           2 :             "Initial states of the (pseudo)random number streams (test 2):"
     391           2 :          CALL poisson%write(output_unit)
     392           2 :          CALL laplace%write(output_unit)
     393           2 :          CALL galois%write(output_unit)
     394           2 :          CALL cantor%write(output_unit)
     395             :       END IF
     396             : 
     397           3 :       sum = sum + poisson%next() + laplace%next() + galois%next() + cantor%next()
     398             : 
     399           3 :       CALL galois%advance(-127, 0)
     400           3 :       sum = sum + galois%next()
     401             : 
     402           3 :       CALL galois%reset_to_next_substream()
     403           3 :       CALL galois%set(extended_precision=.TRUE.)
     404           3 :       sum3 = 0.0_dp
     405      300003 :       DO i = 1, 100000
     406      300003 :          sum3 = sum3 + galois%next()
     407             :       END DO
     408           3 :       sum = sum + sum3/10000.0_dp
     409             : 
     410           3 :       CALL galois%set(antithetic=.TRUE.)
     411           3 :       sum3 = 0.0_dp
     412      300003 :       DO i = 1, 100000
     413      300003 :          sum3 = sum3 + galois%next()
     414             :       END DO
     415           3 :       sum = sum + sum3/10000.0_dp
     416           3 :       CALL galois%set(antithetic=.FALSE.)
     417             : 
     418           3 :       CALL galois%set(extended_precision=.FALSE.)
     419           3 :       sum = sum + poisson%next() + laplace%next() + galois%next() + cantor%next()
     420             : 
     421           3 :       IF (ionode) THEN
     422             :          WRITE (UNIT=output_unit, FMT="(/,T2,A)") &
     423           2 :             "Final states of the (pseudo)random number streams (test 2):"
     424           2 :          CALL poisson%write(output_unit)
     425           2 :          CALL laplace%write(output_unit)
     426           2 :          CALL galois%write(output_unit)
     427           2 :          CALL cantor%write(output_unit)
     428             :          WRITE (UNIT=output_unit, FMT="(/,(T2,A))") &
     429           2 :             "This test routine should print for test 2 the number 39.697547"
     430             :          WRITE (UNIT=output_unit, FMT="(T2,A,F10.6)") &
     431           2 :             "The actual result of test 2 is                      ", sum
     432             :       END IF
     433             : 
     434         549 :    END SUBROUTINE check_rng
     435             : 
     436             : ! **************************************************************************************************
     437             : !> \brief Check that the seeds are legitimate values.
     438             : !> \param seed ...
     439             : ! **************************************************************************************************
     440      108760 :    SUBROUTINE check_seed(seed)
     441             :       REAL(KIND=dp), DIMENSION(3, 2), INTENT(IN)         :: seed
     442             : 
     443             :       CHARACTER(LEN=*), PARAMETER :: fmtstr = "(A,I1,A,ES23.14,A,ES23.14)"
     444             : 
     445             :       CHARACTER(LEN=default_string_length)               :: message
     446             :       INTEGER                                            :: i
     447             : 
     448      435040 :       DO i = 1, 3
     449             : 
     450             :          ! Check condition: 0 <= seed(:,1) < m1
     451             : 
     452      326280 :          IF (seed(i, 1) < 0.0_dp) THEN
     453             :             WRITE (UNIT=message, FMT=fmtstr) &
     454           0 :                "seed(", i, ",1) = ", seed(i, 1), " < ", 0.0_dp
     455           0 :             CALL compress(message)
     456           0 :             CPABORT(message)
     457             :          END IF
     458      326280 :          IF (seed(i, 1) >= m1) THEN
     459             :             WRITE (UNIT=message, FMT=fmtstr) &
     460           0 :                "seed(", i, ",1) = ", seed(i, 1), " >= ", m1
     461           0 :             CALL compress(message)
     462           0 :             CPABORT(message)
     463             :          END IF
     464             : 
     465             :          ! Check condition: 0 <= seed(:,2) < m2
     466             : 
     467      326280 :          IF (seed(i, 2) < 0.0_dp) THEN
     468             :             WRITE (UNIT=message, FMT=fmtstr) &
     469           0 :                "seed(", i, ",2) = ", seed(i, 2), " < ", 0.0_dp
     470           0 :             CALL compress(message)
     471           0 :             CPABORT(message)
     472             :          END IF
     473      435040 :          IF (seed(i, 2) >= m2) THEN
     474             :             WRITE (UNIT=message, FMT=fmtstr) &
     475           0 :                "seed(", i, ",2) = ", seed(i, 2), " >= ", m2
     476           0 :             CALL compress(message)
     477           0 :             CPABORT(message)
     478             :          END IF
     479             : 
     480             :       END DO
     481             : 
     482             :       ! Check condition: first or second seed is 0
     483             : 
     484      108760 :       IF (ALL(seed(:, 1) < 1.0_dp)) THEN
     485           0 :          CPABORT("First seed = 0")
     486             :       END IF
     487             : 
     488      108760 :       IF (ALL(seed(:, 2) < 1.0_dp)) THEN
     489           0 :          CPABORT("Second seed = 0")
     490             :       END IF
     491             : 
     492      108760 :    END SUBROUTINE check_seed
     493             : 
     494             : ! **************************************************************************************************
     495             : !> \brief Create a new RNG stream.
     496             : !> \param name ...
     497             : !> \param last_rng_stream ...
     498             : !> \param distribution_type ...
     499             : !> \param seed ...
     500             : !> \param antithetic ...
     501             : !> \param extended_precision ...
     502             : !> \return ...
     503             : ! **************************************************************************************************
     504       50569 :    FUNCTION rng_stream_constructor(name, last_rng_stream, distribution_type, seed, antithetic, extended_precision) &
     505             :       RESULT(rng_stream)
     506             : 
     507             :       CHARACTER(LEN=*), INTENT(IN)                       :: name
     508             :       TYPE(rng_stream_type), INTENT(IN), OPTIONAL        :: last_rng_stream
     509             :       INTEGER, INTENT(IN), OPTIONAL                      :: distribution_type
     510             :       REAL(KIND=dp), DIMENSION(3, 2), INTENT(IN), &
     511             :          OPTIONAL                                        :: seed
     512             :       LOGICAL, INTENT(IN), OPTIONAL                      :: antithetic, extended_precision
     513             :       TYPE(rng_stream_type)                              :: rng_stream
     514             : 
     515       50569 :       IF (LEN_TRIM(name) .GT. rng_name_length) &
     516           0 :          CPABORT("given random number generator name is too long")
     517             : 
     518       50569 :       rng_stream%name = TRIM(name)
     519             : 
     520       50569 :       IF (PRESENT(seed)) THEN
     521       50294 :          CALL check_seed(seed)
     522      452646 :          rng_stream%ig = seed
     523         275 :       ELSE IF (PRESENT(last_rng_stream)) THEN
     524        1188 :          rng_stream%ig = next_rng_seed(last_rng_stream%ig)
     525             :       ELSE
     526        1287 :          rng_stream%ig = next_rng_seed()
     527             :       END IF
     528             : 
     529      455121 :       rng_stream%cg = rng_stream%ig
     530      455121 :       rng_stream%bg = rng_stream%ig
     531             : 
     532       50569 :       IF (PRESENT(distribution_type)) THEN
     533       98261 :          SELECT CASE (distribution_type)
     534             :          CASE (GAUSSIAN)
     535       47719 :             rng_stream%distribution_type = GAUSSIAN
     536             :          CASE (UNIFORM)
     537        2823 :             rng_stream%distribution_type = UNIFORM
     538             :          CASE DEFAULT
     539       50542 :             CPABORT("Invalid distribution type specified")
     540             :          END SELECT
     541          27 :       ELSE IF (PRESENT(last_rng_stream)) THEN
     542          15 :          rng_stream%distribution_type = last_rng_stream%distribution_type
     543             :       END IF
     544             : 
     545       50569 :       IF (PRESENT(antithetic)) THEN
     546           0 :          rng_stream%antithetic = antithetic
     547       50569 :       ELSE IF (PRESENT(last_rng_stream)) THEN
     548         132 :          rng_stream%antithetic = last_rng_stream%antithetic
     549             :       END IF
     550             : 
     551       50569 :       IF (PRESENT(extended_precision)) THEN
     552       50406 :          rng_stream%extended_precision = extended_precision
     553         163 :       ELSE IF (PRESENT(last_rng_stream)) THEN
     554          35 :          rng_stream%extended_precision = last_rng_stream%extended_precision
     555             :       END IF
     556     1264225 :    END FUNCTION rng_stream_constructor
     557             : 
     558             : ! **************************************************************************************************
     559             : !> \brief Create a RNG stream from a record given as an internal file (string).
     560             : !> \param rng_record ...
     561             : !> \return ...
     562             : ! **************************************************************************************************
     563        1300 :    FUNCTION rng_stream_type_from_record(rng_record) RESULT(rng_stream)
     564             :       CHARACTER(LEN=rng_record_length), INTENT(IN)       :: rng_record
     565             :       TYPE(rng_stream_type)                              :: rng_stream
     566             : 
     567             :       READ (UNIT=rng_record, FMT=rng_record_format) &
     568        1300 :          rng_stream%name, &
     569        1300 :          rng_stream%distribution_type, &
     570        1300 :          rng_stream%antithetic, &
     571        1300 :          rng_stream%extended_precision, &
     572        1300 :          rng_stream%buffer_filled, &
     573        1300 :          rng_stream%buffer, &
     574        1300 :          rng_stream%cg, &
     575        1300 :          rng_stream%bg, &
     576        1300 :          rng_stream%ig
     577       35100 :    END FUNCTION rng_stream_type_from_record
     578             : 
     579             : ! **************************************************************************************************
     580             : !> \brief Dump a RNG stream as a record given as an internal file (string).
     581             : !> \param self ...
     582             : !> \param rng_record ...
     583             : ! **************************************************************************************************
     584       16721 :    SUBROUTINE dump(self, rng_record)
     585             :       CLASS(rng_stream_type), INTENT(IN)                 :: self
     586             :       CHARACTER(LEN=rng_record_length), INTENT(OUT)      :: rng_record
     587             : 
     588       16721 :       rng_record = " "
     589             :       WRITE (UNIT=rng_record, FMT=rng_record_format) &
     590       16721 :          self%name, &
     591       16721 :          self%distribution_type, &
     592       16721 :          self%antithetic, &
     593       16721 :          self%extended_precision, &
     594       16721 :          self%buffer_filled, &
     595       16721 :          self%buffer, &
     596       16721 :          self%cg, &
     597       16721 :          self%bg, &
     598       33442 :          self%ig
     599       16721 :    END SUBROUTINE dump
     600             : 
     601             : ! **************************************************************************************************
     602             : !> \brief Get the components of a RNG stream.
     603             : !> \param self ...
     604             : !> \param name ...
     605             : !> \param distribution_type ...
     606             : !> \param bg ...
     607             : !> \param cg ...
     608             : !> \param ig ...
     609             : !> \param antithetic ...
     610             : !> \param extended_precision ...
     611             : !> \param buffer ...
     612             : !> \param buffer_filled ...
     613             : !> \par History
     614             : !>      2009-11-04 changed bg, cg and ig type from INTEGER, DIMENSION(3, 2)
     615             : !>      to REAL(KIND=dp), DIMENSION(3, 2) [lwalewski]
     616             : !>      2009-11-09 getting the buffer and buffer_filled components
     617             : !>      added [lwalewski]
     618             : ! **************************************************************************************************
     619       16848 :    SUBROUTINE get(self, name, distribution_type, bg, cg, ig, &
     620             :                   antithetic, extended_precision, &
     621             :                   buffer, buffer_filled)
     622             : 
     623             :       CLASS(rng_stream_type), INTENT(IN)                 :: self
     624             :       CHARACTER(LEN=rng_name_length), INTENT(OUT), OPTIONAL :: name
     625             :       INTEGER, INTENT(OUT), OPTIONAL                     :: distribution_type
     626             :       REAL(KIND=dp), DIMENSION(3, 2), INTENT(OUT), &
     627             :          OPTIONAL                                        :: bg, cg, ig
     628             :       LOGICAL, INTENT(OUT), OPTIONAL                     :: antithetic, extended_precision
     629             :       REAL(KIND=dp), INTENT(OUT), OPTIONAL               :: buffer
     630             :       LOGICAL, INTENT(OUT), OPTIONAL                     :: buffer_filled
     631             : 
     632       16848 :       IF (PRESENT(name)) name = self%name
     633       16848 :       IF (PRESENT(distribution_type)) &
     634           0 :          distribution_type = self%distribution_type
     635      130672 :       IF (PRESENT(bg)) bg = self%bg
     636      130672 :       IF (PRESENT(cg)) cg = self%cg
     637      151632 :       IF (PRESENT(ig)) ig = self%ig
     638       16848 :       IF (PRESENT(antithetic)) antithetic = self%antithetic
     639       16848 :       IF (PRESENT(extended_precision)) &
     640           0 :          extended_precision = self%extended_precision
     641       16848 :       IF (PRESENT(buffer)) buffer = self%buffer
     642       16848 :       IF (PRESENT(buffer_filled)) buffer_filled = self%buffer_filled
     643       16848 :    END SUBROUTINE get
     644             : 
     645             : ! **************************************************************************************************
     646             : !> \brief Returns c = MODULO(a*b,m)
     647             : !> \param a ...
     648             : !> \param b ...
     649             : !> \param c ...
     650             : !> \param m ...
     651             : ! **************************************************************************************************
     652        1064 :    PURE SUBROUTINE mat_mat_mod_m(a, b, c, m)
     653             :       REAL(KIND=dp), DIMENSION(3, 3), INTENT(IN)         :: a, b
     654             :       REAL(KIND=dp), DIMENSION(3, 3), INTENT(OUT)        :: c
     655             :       REAL(KIND=dp), INTENT(IN)                          :: m
     656             : 
     657             :       INTEGER                                            :: i
     658             : 
     659        4256 :       DO i = 1, 3
     660        4256 :          CALL mat_vec_mod_m(a, b(:, i), c(:, i), m)
     661             :       END DO
     662             : 
     663        1064 :    END SUBROUTINE mat_mat_mod_m
     664             : 
     665             : ! **************************************************************************************************
     666             : !> \brief Compute matrix b = MODULO(a**n,m)
     667             : !> \param a ...
     668             : !> \param b ...
     669             : !> \param m ...
     670             : !> \param n ...
     671             : ! **************************************************************************************************
     672         224 :    PURE SUBROUTINE mat_pow_mod_m(a, b, m, n)
     673             :       REAL(KIND=dp), DIMENSION(3, 3), INTENT(IN)         :: a
     674             :       REAL(KIND=dp), DIMENSION(3, 3), INTENT(OUT)        :: b
     675             :       REAL(KIND=dp), INTENT(IN)                          :: m
     676             :       INTEGER, INTENT(IN)                                :: n
     677             : 
     678             :       INTEGER                                            :: i
     679             :       REAL(KIND=dp), DIMENSION(3, 3)                     :: u, v, w
     680             : 
     681             :       ! Initialize: u = v = a; b = I
     682             : 
     683         224 :       w = a
     684             : 
     685         224 :       b(1, 1) = 1.0_dp
     686         224 :       b(2, 1) = 0.0_dp
     687         224 :       b(3, 1) = 0.0_dp
     688         224 :       b(1, 2) = 0.0_dp
     689         224 :       b(2, 2) = 1.0_dp
     690         224 :       b(3, 2) = 0.0_dp
     691         224 :       b(1, 3) = 0.0_dp
     692         224 :       b(2, 3) = 0.0_dp
     693         224 :       b(3, 3) = 1.0_dp
     694             : 
     695             :       ! Compute b = MODULO(a**n,m) using the binary decomposition of n
     696             : 
     697         224 :       i = n
     698             : 
     699          16 :       DO
     700         240 :          IF (MODULO(i, 2) /= 0) THEN
     701         228 :             u = w
     702         228 :             v = b
     703         228 :             CALL mat_mat_mod_m(u, v, b, m)
     704             :          END IF
     705         240 :          i = i/2
     706         240 :          IF (i == 0) EXIT
     707          16 :          u = w
     708          16 :          v = w
     709          16 :          CALL mat_mat_mod_m(u, v, w, m)
     710             :       END DO
     711         224 :    END SUBROUTINE mat_pow_mod_m
     712             : 
     713             : ! **************************************************************************************************
     714             : !> \brief Compute matrix b = MODULO(a**(2**e),m)
     715             : !> \param a ...
     716             : !> \param b ...
     717             : !> \param m ...
     718             : !> \param e ...
     719             : ! **************************************************************************************************
     720          14 :    PURE SUBROUTINE mat_two_pow_mod_m(a, b, m, e)
     721             :       REAL(KIND=dp), DIMENSION(3, 3), INTENT(IN)         :: a
     722             :       REAL(KIND=dp), DIMENSION(3, 3), INTENT(OUT)        :: b
     723             :       REAL(KIND=dp), INTENT(IN)                          :: m
     724             :       INTEGER, INTENT(IN)                                :: e
     725             : 
     726             :       INTEGER                                            :: i
     727             :       REAL(KIND=dp), DIMENSION(3, 3)                     :: u, v
     728             : 
     729          14 :       b = a
     730             : 
     731         820 :       DO i = 1, e
     732         806 :          u = b
     733         806 :          v = b
     734         820 :          CALL mat_mat_mod_m(u, v, b, m)
     735             :       END DO
     736             : 
     737          14 :    END SUBROUTINE mat_two_pow_mod_m
     738             : 
     739             : ! **************************************************************************************************
     740             : !> \brief Returns v = MODULO(a*s,m). Assumes that -m < s(i) < m.
     741             : !> \param a ...
     742             : !> \param s ...
     743             : !> \param v ...
     744             : !> \param m ...
     745             : ! **************************************************************************************************
     746      176216 :    PURE SUBROUTINE mat_vec_mod_m(a, s, v, m)
     747             :       REAL(KIND=dp), DIMENSION(3, 3), INTENT(IN)         :: a
     748             :       REAL(KIND=dp), DIMENSION(3), INTENT(IN)            :: s
     749             :       REAL(KIND=dp), DIMENSION(3), INTENT(OUT)           :: v
     750             :       REAL(KIND=dp), INTENT(IN)                          :: m
     751             : 
     752             :       INTEGER                                            :: i, j
     753             :       REAL(KIND=dp)                                      :: a1, a2, c
     754             : 
     755      176216 :       v = 0.0_dp
     756             : 
     757      704864 :       DO i = 1, 3
     758     2290808 :          DO j = 1, 3
     759     1585944 :             a2 = a(i, j)
     760     1585944 :             c = v(i)
     761     1585944 :             v(i) = a2*s(j) + c
     762     1585944 :             IF ((v(i) >= two53) .OR. (v(i) <= -two53)) THEN
     763     1516869 :                a1 = INT(a2/two17)
     764     1516869 :                a2 = a2 - a1*two17
     765     1516869 :                v(i) = a1*s(j)
     766     1516869 :                a1 = INT(v(i)/m)
     767     1516869 :                v(i) = v(i) - a1*m
     768     1516869 :                v(i) = v(i)*two17 + a2*s(j) + c
     769             :             END IF
     770     1585944 :             a1 = INT(v(i)/m)
     771     1585944 :             v(i) = v(i) - a1*m
     772     2114592 :             IF (v(i) < 0.0_dp) v(i) = v(i) + m
     773             :          END DO
     774             :       END DO
     775             : 
     776      176216 :    END SUBROUTINE mat_vec_mod_m
     777             : 
     778             : ! **************************************************************************************************
     779             : !> \brief Get the next integer random number between low and high from the stream
     780             : !> \param self ...
     781             : !> \param low ...
     782             : !> \param high ...
     783             : !> \return ...
     784             : ! **************************************************************************************************
     785       65742 :    FUNCTION next_int(self, low, high) RESULT(u)
     786             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     787             :       INTEGER, INTENT(IN)                                :: low, high
     788             :       INTEGER                                            :: u
     789             : 
     790             :       REAL(KIND=dp)                                      :: r
     791             : 
     792       65742 :       CPASSERT(self%distribution_type == UNIFORM)
     793             : 
     794       65742 :       r = self%next_real()
     795       65742 :       u = low + INT(r*REAL(high - low + 1, dp))
     796       65742 :    END FUNCTION next_int
     797             : 
     798             : ! **************************************************************************************************
     799             : !> \brief Get the next real random number from the stream rng_stream.
     800             : !> \param self ...
     801             : !> \param variance variance of the Gaussian distribution (defaults to 1)
     802             : !> \return ...
     803             : ! **************************************************************************************************
     804    46736205 :    FUNCTION next_real(self, variance) RESULT(u)
     805             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     806             :       REAL(KIND=dp), INTENT(IN), OPTIONAL                :: variance
     807             :       REAL(KIND=dp)                                      :: u
     808             : 
     809             :       REAL(KIND=dp)                                      :: f, r, u1, u2, var
     810             : 
     811    83749933 :       SELECT CASE (self%distribution_type)
     812             :       CASE (GAUSSIAN)
     813    37013728 :          var = 1.0_dp
     814    37013728 :          IF (PRESENT(variance)) var = variance
     815             :          ! take the random number from the buffer, if the buffer is filled
     816    37013728 :          IF (self%buffer_filled) THEN
     817    18496934 :             u = SQRT(var)*self%buffer
     818    18496934 :             self%buffer_filled = .FALSE.
     819             :          ELSE
     820             :             DO
     821    23570553 :                IF (self%extended_precision) THEN
     822    23570553 :                   u1 = 2.0_dp*rn53(self) - 1.0_dp
     823    23570553 :                   u2 = 2.0_dp*rn53(self) - 1.0_dp
     824             :                ELSE
     825           0 :                   u1 = 2.0_dp*rn32(self) - 1.0_dp
     826           0 :                   u2 = 2.0_dp*rn32(self) - 1.0_dp
     827             :                END IF
     828    23570553 :                r = u1*u1 + u2*u2
     829    23570553 :                IF ((r > 0.0_dp) .AND. (r < 1.0_dp)) EXIT
     830             :             END DO
     831             :             ! Box-Muller transformation
     832    18516794 :             f = SQRT(-2.0_dp*LOG(r)/r)
     833    18516794 :             u = SQRT(var)*f*u1
     834             :             ! save the second random number for the next call
     835    18516794 :             self%buffer = f*u2
     836    18516794 :             self%buffer_filled = .TRUE.
     837             :          END IF
     838             :       CASE (UNIFORM)
     839    46736205 :          IF (self%extended_precision) THEN
     840     9052033 :             u = rn53(self)
     841             :          ELSE
     842      670444 :             u = rn32(self)
     843             :          END IF
     844             :       END SELECT
     845    46736205 :    END FUNCTION next_real
     846             : 
     847             : ! **************************************************************************************************
     848             : !> \brief Get the seed for the next RNG stream w.r.t. a given seed.
     849             : !> \param seed If the optional argument seed is missing, then the default seed is returned.
     850             : !> \return ...
     851             : ! **************************************************************************************************
     852       58781 :    FUNCTION next_rng_seed(seed) RESULT(next_seed)
     853             :       REAL(KIND=dp), DIMENSION(3, 2), INTENT(IN), &
     854             :          OPTIONAL                                        :: seed
     855             :       REAL(KIND=dp), DIMENSION(3, 2)                     :: next_seed
     856             : 
     857       58781 :       IF (PRESENT(seed)) THEN
     858       58466 :          CALL check_seed(seed)
     859       58466 :          CALL mat_vec_mod_m(a1p127, seed(:, 1), next_seed(:, 1), m1)
     860       58466 :          CALL mat_vec_mod_m(a2p127, seed(:, 2), next_seed(:, 2), m2)
     861             :       ELSE
     862        2835 :          next_seed = 12345.0_dp ! default seed
     863             :       END IF
     864             : 
     865       58781 :    END FUNCTION next_rng_seed
     866             : 
     867             : ! **************************************************************************************************
     868             : !> \brief Fill entity array with random numbers from the RNG stream rng_stream
     869             : !> \param self ...
     870             : !> \param array ...
     871             : ! **************************************************************************************************
     872       18889 :    SUBROUTINE fill_1(self, array)
     873             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     874             :       REAL(KIND=dp), DIMENSION(:), INTENT(OUT)           :: array
     875             : 
     876             :       INTEGER                                            :: i
     877             : 
     878     1547430 :       DO i = 1, SIZE(array)
     879     1547430 :          array(i) = self%next()
     880             :       END DO
     881       18889 :    END SUBROUTINE fill_1
     882             : 
     883             : ! **************************************************************************************************
     884             : !> \brief ...
     885             : !> \param self ...
     886             : !> \param array ...
     887             : ! **************************************************************************************************
     888           0 :    SUBROUTINE fill_2(self, array)
     889             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     890             :       REAL(KIND=dp), DIMENSION(:, :), INTENT(OUT)         :: array
     891             : 
     892             :       INTEGER                                            :: i, j
     893             : 
     894           0 :       DO j = 1, SIZE(array, 2)
     895           0 :          DO i = 1, SIZE(array, 1)
     896           0 :             array(i, j) = self%next()
     897             :          END DO
     898             :       END DO
     899           0 :    END SUBROUTINE fill_2
     900             : 
     901             : ! **************************************************************************************************
     902             : !> \brief ...
     903             : !> \param self ...
     904             : !> \param array ...
     905             : ! **************************************************************************************************
     906           0 :    SUBROUTINE fill_3(self, array)
     907             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     908             :       REAL(KIND=dp), DIMENSION(:, :, :), INTENT(OUT)       :: array
     909             : 
     910             :       INTEGER                                            :: i, j, k
     911             : 
     912           0 :       DO k = 1, SIZE(array, 3)
     913           0 :          DO j = 1, SIZE(array, 2)
     914           0 :             DO i = 1, SIZE(array, 1)
     915           0 :                array(i, j, k) = self%next()
     916             :             END DO
     917             :          END DO
     918             :       END DO
     919           0 :    END SUBROUTINE fill_3
     920             : 
     921             : ! **************************************************************************************************
     922             : !> \brief Reset a random number stream to its initial state.
     923             : !> \param self ...
     924             : ! **************************************************************************************************
     925          13 :    SUBROUTINE reset(self)
     926             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     927             : 
     928         117 :       self%cg = self%ig
     929         117 :       self%bg = self%ig
     930          13 :    END SUBROUTINE reset
     931             : 
     932             : ! **************************************************************************************************
     933             : !> \brief Reset a random number stream to the beginning of its current substream.
     934             : !> \param self ...
     935             : ! **************************************************************************************************
     936           3 :    SUBROUTINE reset_to_substream(self)
     937             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     938             : 
     939          27 :       self%cg = self%bg
     940           3 :    END SUBROUTINE reset_to_substream
     941             : 
     942             : ! **************************************************************************************************
     943             : !> \brief Reset a random number stream to the beginning of its next substream.
     944             : !> \param self ...
     945             : ! **************************************************************************************************
     946       27934 :    SUBROUTINE reset_to_next_substream(self)
     947             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
     948             : 
     949             :       REAL(KIND=dp), DIMENSION(3, 2)                     :: u
     950             : 
     951       27934 :       u = 0.0_dp
     952             : 
     953       27934 :       CALL mat_vec_mod_m(a1p76, self%bg(:, 1), u(:, 1), m1)
     954       27934 :       CALL mat_vec_mod_m(a2p76, self%bg(:, 2), u(:, 2), m2)
     955             : 
     956      251406 :       self%bg = u
     957      251406 :       self%cg = u
     958       27934 :    END SUBROUTINE reset_to_next_substream
     959             : 
     960             : ! **************************************************************************************************
     961             : !> \brief Generate the next random number with standard precision (32 bits)
     962             : !> \param rng_stream ...
     963             : !> \return ...
     964             : ! **************************************************************************************************
     965   113056722 :    FUNCTION rn32(rng_stream) RESULT(u)
     966             :       TYPE(rng_stream_type)                              :: rng_stream
     967             :       REAL(KIND=dp)                                      :: u
     968             : 
     969             :       INTEGER                                            :: k
     970             :       REAL(KIND=dp)                                      :: p1, p2
     971             : 
     972             :       ! Component 1
     973             : 
     974   113056722 :       p1 = a12*rng_stream%cg(2, 1) - a13n*rng_stream%cg(1, 1)
     975   113056722 :       k = INT(p1/m1)
     976   113056722 :       p1 = p1 - k*m1
     977   113056722 :       IF (p1 < 0.0_dp) p1 = p1 + m1
     978   113056722 :       rng_stream%cg(1, 1) = rng_stream%cg(2, 1)
     979   113056722 :       rng_stream%cg(2, 1) = rng_stream%cg(3, 1)
     980   113056722 :       rng_stream%cg(3, 1) = p1
     981             : 
     982             :       ! Component 2
     983             : 
     984   113056722 :       p2 = a21*rng_stream%cg(3, 2) - a23n*rng_stream%cg(1, 2)
     985   113056722 :       k = INT(p2/m2)
     986   113056722 :       p2 = p2 - k*m2
     987   113056722 :       IF (p2 < 0.0_dp) p2 = p2 + m2
     988   113056722 :       rng_stream%cg(1, 2) = rng_stream%cg(2, 2)
     989   113056722 :       rng_stream%cg(2, 2) = rng_stream%cg(3, 2)
     990   113056722 :       rng_stream%cg(3, 2) = p2
     991             : 
     992             :       ! Combination
     993             : 
     994   113056722 :       IF (p1 > p2) THEN
     995    56505610 :          u = (p1 - p2)*norm
     996             :       ELSE
     997    56551112 :          u = (p1 - p2 + m1)*norm
     998             :       END IF
     999             : 
    1000   113056722 :       IF (rng_stream%antithetic) u = 1.0_dp - u
    1001             : 
    1002   113056722 :    END FUNCTION rn32
    1003             : 
    1004             : ! **************************************************************************************************
    1005             : !> \brief Generate the next random number with extended precision (53 bits)
    1006             : !> \param rng_stream ...
    1007             : !> \return ...
    1008             : ! **************************************************************************************************
    1009    56193139 :    FUNCTION rn53(rng_stream) RESULT(u)
    1010             :       TYPE(rng_stream_type)                              :: rng_stream
    1011             :       REAL(KIND=dp)                                      :: u
    1012             : 
    1013    56193139 :       u = rn32(rng_stream)
    1014             : 
    1015             :       ! Note: rn32 returns 1 - u in the antithetic case
    1016             : 
    1017    56193139 :       IF (rng_stream%antithetic) THEN
    1018      300000 :          u = u + (rn32(rng_stream) - 1.0_dp)*fact
    1019      300000 :          IF (u < 0.0_dp) u = u + 1.0_dp
    1020             :       ELSE
    1021    55893139 :          u = u + rn32(rng_stream)*fact
    1022    55893139 :          IF (u >= 1.0_dp) u = u - 1.0_dp
    1023             :       END IF
    1024    56193139 :    END FUNCTION rn53
    1025             : 
    1026             : ! **************************************************************************************************
    1027             : !> \brief Set the components of a RNG stream.
    1028             : !> \param self ...
    1029             : !> \param name ...
    1030             : !> \param distribution_type ...
    1031             : !> \param bg ...
    1032             : !> \param cg ...
    1033             : !> \param ig ...
    1034             : !> \param seed ...
    1035             : !> \param antithetic ...
    1036             : !> \param extended_precision ...
    1037             : !> \param buffer ...
    1038             : !> \param buffer_filled ...
    1039             : !> \par History
    1040             : !>      2009-11-09 setting the buffer and buffer_filled components
    1041             : !>      added [lwalewski]
    1042             : ! **************************************************************************************************
    1043       13957 :    SUBROUTINE set(self, name, distribution_type, bg, cg, ig, &
    1044             :                   seed, antithetic, extended_precision, &
    1045             :                   buffer, buffer_filled)
    1046             : 
    1047             :       ! NOTE: The manipulation of an active RNG stream is discouraged.
    1048             : 
    1049             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
    1050             :       CHARACTER(LEN=*), INTENT(IN), OPTIONAL             :: name
    1051             :       INTEGER, INTENT(IN), OPTIONAL                      :: distribution_type
    1052             :       REAL(KIND=dp), DIMENSION(3, 2), INTENT(IN), &
    1053             :          OPTIONAL                                        :: bg, cg, ig, seed
    1054             :       LOGICAL, INTENT(IN), OPTIONAL                      :: antithetic, extended_precision
    1055             :       REAL(KIND=dp), INTENT(IN), OPTIONAL                :: buffer
    1056             :       LOGICAL, INTENT(IN), OPTIONAL                      :: buffer_filled
    1057             : 
    1058           0 :       IF (PRESENT(name)) self%name = name
    1059       13957 :       IF (PRESENT(distribution_type)) THEN
    1060           0 :          self%distribution_type = distribution_type
    1061             :       END IF
    1062      125493 :       IF (PRESENT(bg)) self%bg = bg
    1063      125493 :       IF (PRESENT(cg)) self%cg = cg
    1064      125493 :       IF (PRESENT(ig)) self%ig = ig
    1065       13957 :       IF (PRESENT(seed)) THEN
    1066             :          ! Sets the initial seed of the stream to seed
    1067             :          ! NOTE: The use of this method is discouraged
    1068           0 :          CALL check_seed(seed)
    1069           0 :          self%ig = seed
    1070           0 :          self%cg = seed
    1071           0 :          self%bg = seed
    1072             :       END IF
    1073       13957 :       IF (PRESENT(antithetic)) self%antithetic = antithetic
    1074       13957 :       IF (PRESENT(extended_precision)) THEN
    1075           6 :          self%extended_precision = extended_precision
    1076             :       END IF
    1077       13957 :       IF (PRESENT(buffer)) self%buffer = buffer
    1078       13957 :       IF (PRESENT(buffer_filled)) self%buffer_filled = buffer_filled
    1079       13957 :    END SUBROUTINE set
    1080             : 
    1081             : ! **************************************************************************************************
    1082             : !> \brief Write the transformation matrices of the two MRG components (raised to the specified output)
    1083             : !> \param output_unit ...
    1084             : ! **************************************************************************************************
    1085           1 :    SUBROUTINE write_rng_matrices(output_unit)
    1086             :       INTEGER, INTENT(IN)                                :: output_unit
    1087             : 
    1088             :       CHARACTER(LEN=40)                                  :: fmtstr
    1089             :       INTEGER                                            :: i, j
    1090             : 
    1091             :       ! Print the transformation matrices for both components
    1092             : 
    1093             :       WRITE (UNIT=output_unit, FMT="(/,T2,A)") &
    1094             :          "TRANSFORMATION MATRICES FOR THE PARALLEL (PSEUDO)RANDOM NUMBER "// &
    1095           1 :          "GENERATOR"
    1096             : 
    1097           1 :       fmtstr = "(/,T4,A,/,/,(2X,3F14.1))"
    1098             : 
    1099             :       WRITE (UNIT=output_unit, FMT=fmtstr) &
    1100           4 :          "A1", ((a1p0(i, j), j=1, 3), i=1, 3)
    1101             : 
    1102             :       WRITE (UNIT=output_unit, FMT=fmtstr) &
    1103           4 :          "A2", ((a2p0(i, j), j=1, 3), i=1, 3)
    1104             : 
    1105             :       WRITE (UNIT=output_unit, FMT=fmtstr) &
    1106           4 :          "A1**(2**76)", ((a1p76(i, j), j=1, 3), i=1, 3)
    1107             : 
    1108             :       WRITE (UNIT=output_unit, FMT=fmtstr) &
    1109           4 :          "A2**(2**76)", ((a2p76(i, j), j=1, 3), i=1, 3)
    1110             : 
    1111             :       WRITE (UNIT=output_unit, FMT=fmtstr) &
    1112           4 :          "A1**(2**127)", ((a1p127(i, j), j=1, 3), i=1, 3)
    1113             : 
    1114             :       WRITE (UNIT=output_unit, FMT=fmtstr) &
    1115           4 :          "A2**(2**127)", ((a2p127(i, j), j=1, 3), i=1, 3)
    1116             : 
    1117           1 :    END SUBROUTINE write_rng_matrices
    1118             : 
    1119             : ! **************************************************************************************************
    1120             : !> \brief ...
    1121             : !> \param self ...
    1122             : !> \param output_unit ...
    1123             : !> \param write_all if .TRUE., then print all stream informations (the default is .FALSE.).
    1124             : ! **************************************************************************************************
    1125          33 :    SUBROUTINE write (self, output_unit, write_all)
    1126             :       CLASS(rng_stream_type), INTENT(IN)                 :: self
    1127             :       INTEGER, INTENT(IN)                                :: output_unit
    1128             :       LOGICAL, INTENT(IN), OPTIONAL                      :: write_all
    1129             : 
    1130             :       LOGICAL                                            :: my_write_all
    1131             : 
    1132          33 :       my_write_all = .FALSE.
    1133             : 
    1134          33 :       IF (PRESENT(write_all)) &
    1135           2 :          my_write_all = write_all
    1136             : 
    1137             :       WRITE (UNIT=output_unit, FMT="(/,T2,A,/)") &
    1138          33 :          "Random number stream <"//TRIM(self%name)//">:"
    1139             : 
    1140          36 :       SELECT CASE (self%distribution_type)
    1141             :       CASE (GAUSSIAN)
    1142             :          WRITE (UNIT=output_unit, FMT="(T4,A)") &
    1143             :             "Distribution type: "// &
    1144           3 :             "Normal Gaussian distribution with zero mean"
    1145             :       CASE (UNIFORM)
    1146             :          WRITE (UNIT=output_unit, FMT="(T4,A)") &
    1147             :             "Distribution type: "// &
    1148          33 :             "Uniform distribution [0,1] with 1/2 mean"
    1149             :       END SELECT
    1150             : 
    1151          33 :       IF (self%antithetic) THEN
    1152           2 :          WRITE (UNIT=output_unit, FMT="(T4,A)") "Antithetic:        yes"
    1153             :       ELSE
    1154          31 :          WRITE (UNIT=output_unit, FMT="(T4,A)") "Antithetic:        no"
    1155             :       END IF
    1156             : 
    1157          33 :       IF (self%extended_precision) THEN
    1158           5 :          WRITE (UNIT=output_unit, FMT="(T4,A)") "Precision:         53 Bit"
    1159             :       ELSE
    1160          28 :          WRITE (UNIT=output_unit, FMT="(T4,A)") "Precision:         32 Bit"
    1161             :       END IF
    1162             : 
    1163          33 :       IF (my_write_all) THEN
    1164             : 
    1165             :          WRITE (UNIT=output_unit, FMT="(/,T4,A,/,/,(T4,A,3F20.1))") &
    1166           2 :             "Initial state of the stream:", &
    1167           2 :             "Component 1:", self%ig(:, 1), &
    1168           4 :             "Component 2:", self%ig(:, 2)
    1169             : 
    1170             :          WRITE (UNIT=output_unit, FMT="(/,T4,A,/,/,(T4,A,3F20.1))") &
    1171           2 :             "Initial state of the current substream:", &
    1172           2 :             "Component 1:", self%bg(:, 1), &
    1173           4 :             "Component 2:", self%bg(:, 2)
    1174             : 
    1175             :       END IF
    1176             : 
    1177             :       WRITE (UNIT=output_unit, FMT="(/,T4,A,/,/,(T4,A,3F20.1))") &
    1178          33 :          "Current state of the stream:", &
    1179          33 :          "Component 1:", self%cg(:, 1), &
    1180          66 :          "Component 2:", self%cg(:, 2)
    1181          33 :    END SUBROUTINE write
    1182             : 
    1183             : ! **************************************************************************************************
    1184             : !> \brief Shuffle an array of integers (using the Fisher-Yates shuffle)
    1185             : !> \param self ...
    1186             : !> \param arr the integer array to be shuffled
    1187             : ! **************************************************************************************************
    1188          54 :    SUBROUTINE shuffle(self, arr)
    1189             :       CLASS(rng_stream_type), INTENT(INOUT)              :: self
    1190             :       INTEGER, DIMENSION(:), INTENT(INOUT)               :: arr
    1191             : 
    1192             :       INTEGER                                            :: idxa, idxb, tmp
    1193             : 
    1194         152 :       DO idxa = UBOUND(arr, 1), LBOUND(arr, 1) + 1, -1
    1195          44 :          idxb = self%next(LBOUND(arr, 1), idxa)
    1196          44 :          tmp = arr(idxa)
    1197          44 :          arr(idxa) = arr(idxb)
    1198          98 :          arr(idxb) = tmp
    1199             :       END DO
    1200          54 :    END SUBROUTINE
    1201             : 
    1202           0 : END MODULE parallel_rng_types

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