eesupp/src/exch_cycle_ebl.F

C $Header: /u/gcmpack/models/MITgcmUV/eesupp/src/exch_cycle_ebl.F,v 1.1 1998/09/29 18:53:44 cnh Exp $
C $Name: $

      SUBROUTINE EXCH_CYCLE_EBL( myThid )
C     /==========================================================\
C     | SUBROUTINE EXCH_CYCLE_EBL                                |
C     | o Cycle exchange buffer level.                           |
C     |==========================================================|
C     | Step the "exchange buffer level" to next value.          |
C     | The buffer level is used to prevent consecutive messages |
C     | overwriting one another. Because we know that every tile |
C     | will participate in an exchange we can be sure that every|
C     | tile will cycle through the buffers with the same        |
C     | sequence. Also we know that a tile cannot start a new    |
C     | exchange before it has completed its end of the previous |
C     | exchange. Thus by cycling through three buffer levels we |
C     | can be sure that the buffer we write to will be free.    |
C     |  That is by the time we are participating in the third   |
C     | exchange transaction we know that both ends of the first |
C     | transaction must have completed.                         |
C     | Note --                                                  |
C     | 1. We allow more than three levels below although this   |
C     | is not necessary.                                        |
C     \==========================================================/
      IMPLICIT NONE
C     == Global data ==
#include "SIZE.h"
#include "EEPARAMS.h"
#include "EESUPPORT.h"
#include "EXCH.h"

C     == Routine arguments ==
C     myThid - Thread number of this instance of the routine
      INTEGER myThid

C     == Local variables ==
C     bi, bj - Loop counters
      INTEGER bi, bj

      DO bj=myByLo(myThid),myByHi(myThid)
       DO bi=myBxLo(myThid),myBxHi(myThid)
C--     Use next level exchange buffer in cycle.
        exchangeBufLevel(1,bi,bj) = exchangeBufLevel(1,bi,bj)+1
        IF ( exchangeBufLevel(1,bi,bj) .GT. NUMBER_OF_BUFFER_LEVELS )
     &   exchangeBufLevel(1,bi,bj) = 1
       ENDDO
      ENDDO

      RETURN
      END
1	C $Header: /u/gcmpack/models/MITgcmUV/eesupp/src/exch_cycle_ebl.F,v 1.1 1998/09/29 18:53:44 cnh Exp $
2	C $Name: $
3
4	SUBROUTINE EXCH_CYCLE_EBL( myThid )
5	C /==========================================================\
6	C \| SUBROUTINE EXCH_CYCLE_EBL \|
7	C \| o Cycle exchange buffer level. \|
8	C \|==========================================================\|
9	C \| Step the "exchange buffer level" to next value. \|
10	C \| The buffer level is used to prevent consecutive messages \|
11	C \| overwriting one another. Because we know that every tile \|
12	C \| will participate in an exchange we can be sure that every\|
13	C \| tile will cycle through the buffers with the same \|
14	C \| sequence. Also we know that a tile cannot start a new \|
15	C \| exchange before it has completed its end of the previous \|
16	C \| exchange. Thus by cycling through three buffer levels we \|
17	C \| can be sure that the buffer we write to will be free. \|
18	C \| That is by the time we are participating in the third \|
19	C \| exchange transaction we know that both ends of the first \|
20	C \| transaction must have completed. \|
21	C \| Note -- \|
22	C \| 1. We allow more than three levels below although this \|
23	C \| is not necessary. \|
24	C \==========================================================/
25	IMPLICIT NONE
26	C == Global data ==
27	#include "SIZE.h"
28	#include "EEPARAMS.h"
29	#include "EESUPPORT.h"
30	#include "EXCH.h"
31
32	C == Routine arguments ==
33	C myThid - Thread number of this instance of the routine
34	INTEGER myThid
35
36	C == Local variables ==
37	C bi, bj - Loop counters
38	INTEGER bi, bj
39
40	DO bj=myByLo(myThid),myByHi(myThid)
41	DO bi=myBxLo(myThid),myBxHi(myThid)
42	C-- Use next level exchange buffer in cycle.
43	exchangeBufLevel(1,bi,bj) = exchangeBufLevel(1,bi,bj)+1
44	IF ( exchangeBufLevel(1,bi,bj) .GT. NUMBER_OF_BUFFER_LEVELS )
45	& exchangeBufLevel(1,bi,bj) = 1
46	ENDDO
47	ENDDO
48
49	RETURN
50	END