source: LMDZ6/branches/Amaury_dev/libf/misc/lmdz_ran1.f90 @ 5419

Last change on this file since 5419 was 5117, checked in by abarral, 5 months ago

rename modules properly lmdz_*
move some unused files to obsolete/
(lint) uppercase fortran keywords
  • Property copyright set to
    Name of program: LMDZ
    Creation date: 1984
    Version: LMDZ5
    License: CeCILL version 2
    Holder: Laboratoire de m\'et\'eorologie dynamique, CNRS, UMR 8539
    See the license file in the root directory
  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 1.1 KB
Line 
1! $Id: lmdz_ran1.f90 5117 2024-07-24 14:23:34Z evignon $
2
3MODULE lmdz_ran1
4  IMPLICIT NONE; PRIVATE
5  PUBLIC ran1
6CONTAINS
7
8  FUNCTION RAN1(IDUM)
9    IMPLICIT NONE
10    REAL :: RAN1
11    REAL, SAVE :: R(97)
12    REAL, PARAMETER :: RM1 = 3.8580247E-6, RM2 = 7.4373773E-6
13    INTEGER, SAVE :: IFF = 0
14    INTEGER, save :: ix1, ix2, ix3
15    INTEGER, PARAMETER :: M1 = 259200, IA1 = 7141, IC1 = 54773
16    INTEGER, PARAMETER :: M2 = 134456, IA2 = 8121, IC2 = 28411
17    INTEGER, PARAMETER :: M3 = 243000, IA3 = 4561, IC3 = 51349
18    INTEGER :: IDUM, J
19
20    IF (IDUM<0.OR.IFF==0) THEN
21      IFF = 1
22      IX1 = MOD(IC1 - IDUM, M1)
23      IX1 = MOD(IA1 * IX1 + IC1, M1)
24      IX2 = MOD(IX1, M2)
25      IX1 = MOD(IA1 * IX1 + IC1, M1)
26      IX3 = MOD(IX1, M3)
27      DO J = 1, 97
28        IX1 = MOD(IA1 * IX1 + IC1, M1)
29        IX2 = MOD(IA2 * IX2 + IC2, M2)
30        R(J) = (REAL(IX1) + REAL(IX2) * RM2) * RM1
31      END DO
32      IDUM = 1
33    ENDIF
34    IX1 = MOD(IA1 * IX1 + IC1, M1)
35    IX2 = MOD(IA2 * IX2 + IC2, M2)
36    IX3 = MOD(IA3 * IX3 + IC3, M3)
37    J = 1 + (97 * IX3) / M3
38    IF(J>97.OR.J<1) stop 1
39    RAN1 = R(J)
40    R(J) = (REAL(IX1) + REAL(IX2) * RM2) * RM1
41
42  END FUNCTION RAN1
43END MODULE lmdz_ran1
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