eesupp/inc/GLOBAL_SUM.h

C $Header: /u/gcmpack/models/MITgcmUV/eesupp/inc/Attic/GLOBAL_SUM.h,v 1.1.2.1 2001/04/12 10:52:48 cnh Exp $
C $Name: pre38-close $
C
C     /==========================================================\
C     | GLOBA:_SUM.h                                             |
C     | o Globals used by Fortran global sum routine.            |
C     |==========================================================|
C     | The global sum shared memory scheme uses global heap data|
C     | structures (.i.e COMMON blocks ). Each thread writes to  |
C     | an its own element of the shared memory array and then   |
C     | one thread reads all the entries and sums them. The sum  |
C     | result is then read by all threads.                      |
C     | Remember - you are working with regions of memory that   |
C     | are being updated concurrently by different threads.     |
C     | What happens, when it happens and who gets to see what   |
C     | happens at what stage depends on the computer systems    |
C     | memory model. Every computer has a different memory model|
C     | and they are never simple. In all current platforms it is|
C     | possible for one thread to see events happening in a     |
C     | different order from the order they are written in the   |
C     | code.                                                    |
C     | Unless you understand this it is not a good idea to      |
C     | make modifications te way these header files are setup or|
C     | the way the global sum routines work.                    |
C     \==========================================================/
      COMMON / GSUM_COMMON_R8 / phiGSRL
      Real*8  phiGSRL(lShare8, MAX_NO_THREADS )

      COMMON / GSUM_COMMON_R4 / phiGSRS
      Real*4  phiGSRS(lShare4, MAX_NO_THREADS )

      COMMON / GSUM_COMMON_I  / phiGSI
      INTEGER phiGSI (lShare4, MAX_NO_THREADS )
1	adcroft	1.2	C $Header: /u/gcmpack/models/MITgcmUV/eesupp/inc/Attic/GLOBAL_SUM.h,v 1.1.2.1 2001/04/12 10:52:48 cnh Exp $
2			C $Name: pre38-close $
3			C
4			C /==========================================================\
5			C \| GLOBA:_SUM.h \|
6			C \| o Globals used by Fortran global sum routine. \|
7			C \|==========================================================\|
8			C \| The global sum shared memory scheme uses global heap data\|
9			C \| structures (.i.e COMMON blocks ). Each thread writes to \|
10			C \| an its own element of the shared memory array and then \|
11			C \| one thread reads all the entries and sums them. The sum \|
12			C \| result is then read by all threads. \|
13			C \| Remember - you are working with regions of memory that \|
14			C \| are being updated concurrently by different threads. \|
15			C \| What happens, when it happens and who gets to see what \|
16			C \| happens at what stage depends on the computer systems \|
17			C \| memory model. Every computer has a different memory model\|
18			C \| and they are never simple. In all current platforms it is\|
19			C \| possible for one thread to see events happening in a \|
20			C \| different order from the order they are written in the \|
21			C \| code. \|
22			C \| Unless you understand this it is not a good idea to \|
23			C \| make modifications te way these header files are setup or\|
24			C \| the way the global sum routines work. \|
25			C \==========================================================/
26			COMMON / GSUM_COMMON_R8 / phiGSRL
27			Real*8 phiGSRL(lShare8, MAX_NO_THREADS )
28
29			COMMON / GSUM_COMMON_R4 / phiGSRS
30			Real*4 phiGSRS(lShare4, MAX_NO_THREADS )
31
32			COMMON / GSUM_COMMON_I / phiGSI
33			INTEGER phiGSI (lShare4, MAX_NO_THREADS )