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C $Header: /u/gcmpack/MITgcm/eesupp/src/global_max.F,v 1.12 2009/06/10 03:47:03 jmc Exp $ |
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C $Name: $ |
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|
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#include "CPP_EEOPTIONS.h" |
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|
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C-- File global_max.F: Routines that perform global max reduction on an array |
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C of thread values. |
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C Contents |
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C o GLOBAL_MAX_R4 |
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C o GLOBAL_MAX_R8 |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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CBOP |
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C !ROUTINE: GLOBAL_MAX_R4 |
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|
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C !INTERFACE: |
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SUBROUTINE GLOBAL_MAX_R4( |
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U maxPhi, |
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I myThid ) |
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|
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C !DESCRIPTION: |
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C *==========================================================* |
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C | SUBROUTINE GLOBAL\_MAX\_R4 |
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C | o Handle max for real*4 data. |
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C *==========================================================* |
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C | Perform max on array of one value per thread and then |
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C | max result of all the processes. |
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C | Notes |
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C | ===== |
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C | Within a process only one thread does the max, each |
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C | thread is assumed to have already maxed its local data. |
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C | The same thread also does the inter-process max for |
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C | example with MPI and then writes the result into a shared |
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C | location. All threads wait until the max is avaiailable. |
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C *==========================================================* |
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|
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C !USES: |
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IMPLICIT NONE |
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|
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C == Global data == |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "EESUPPORT.h" |
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#include "GLOBAL_MAX.h" |
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|
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine arguments == |
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C maxPhi :: Result of max. |
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C myThid :: My thread id. |
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Real*4 maxPhi |
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INTEGER myThid |
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|
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C !LOCAL VARIABLES: |
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C == Local variables == |
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C I :: Loop counters |
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C mpiRC :: MPI return code |
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INTEGER I |
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Real*4 tmp |
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#ifdef ALLOW_USE_MPI |
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INTEGER mpiRC |
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#endif /* ALLOW_USE_MPI */ |
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CEOP |
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|
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C-- write local max into array |
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phiGMR4(1,myThid) = maxPhi |
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|
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C-- Can not start until everyone is ready |
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CALL BAR2( myThid ) |
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|
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C-- Max within the process first |
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_BEGIN_MASTER( myThid ) |
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tmp = phiGMR4(1,1) |
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DO I=2,nThreads |
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tmp = MAX(tmp,phiGMR4(1,I)) |
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ENDDO |
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maxPhi = tmp |
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#ifdef ALLOW_USE_MPI |
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IF ( usingMPI ) THEN |
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CALL MPI_Allreduce(tmp,maxPhi,1,MPI_REAL,MPI_MAX, |
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& MPI_COMM_MODEL,mpiRC) |
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ENDIF |
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#endif /* ALLOW_USE_MPI */ |
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phiGMR4(1,0) = maxPhi |
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_END_MASTER( myThid ) |
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|
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C-- Do not leave until we are sure that the max is done |
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CALL BAR2( myThid ) |
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|
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C-- set result for every process |
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maxPhi = phiGMR4(1,0) |
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|
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RETURN |
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END |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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CBOP |
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C !ROUTINE: GLOBAL_MAX_R8 |
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|
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C !INTERFACE: |
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SUBROUTINE GLOBAL_MAX_R8( |
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O maxPhi, |
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I myThid ) |
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|
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C !DESCRIPTION: |
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C *==========================================================* |
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C | SUBROUTINE GLOBAL\_MAX\_R8 |
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C | o Handle max for real*8 data. |
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C *==========================================================* |
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C | Perform max on array of one value per thread and then |
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C | max result of all the processes. |
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C | Notes |
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C | ===== |
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C | Within a process only one thread does the max, each |
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C | thread is assumed to have already maxed its local data. |
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C | The same thread also does the inter-process max for |
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C | example with MPI and then writes the result into a shared |
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C | location. All threads wait until the max is avaiailable. |
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C *==========================================================* |
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|
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C !USES: |
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IMPLICIT NONE |
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|
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C === Global data === |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "EESUPPORT.h" |
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#include "GLOBAL_MAX.h" |
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|
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C !INPUT/OUTPUT PARAMETERS: |
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C === Routine arguments === |
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C maxPhi :: Result of max. |
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C myThid :: My thread id. |
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Real*8 maxPhi |
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INTEGER myThid |
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|
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C !LOCAL VARIABLES: |
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C === Local variables === |
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C I :: Loop counters |
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C mpiRC :: MPI return code |
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INTEGER I |
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Real*8 tmp |
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#ifdef ALLOW_USE_MPI |
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INTEGER mpiRC |
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#endif /* ALLOW_USE_MPI */ |
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CEOP |
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|
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C-- write local max into array |
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phiGMR8(1,myThid) = maxPhi |
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|
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C-- Can not start until everyone is ready |
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CALL BAR2( myThid ) |
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|
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C-- Max within the process first |
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_BEGIN_MASTER( myThid ) |
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tmp = phiGMR8(1,1) |
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DO I=2,nThreads |
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tmp = MAX(tmp,phiGMR8(1,I)) |
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ENDDO |
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maxPhi = tmp |
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#ifdef ALLOW_USE_MPI |
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IF ( usingMPI ) THEN |
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CALL MPI_Allreduce(tmp,maxPhi,1,MPI_DOUBLE_PRECISION,MPI_MAX, |
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& MPI_COMM_MODEL,mpiRC) |
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ENDIF |
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#endif /* ALLOW_USE_MPI */ |
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C-- Write solution to place where all threads can see it |
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phiGMR8(1,0) = maxPhi |
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_END_MASTER( myThid ) |
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|
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C-- Do not leave until we are sure that the max is done |
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CALL BAR2( myThid ) |
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|
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C-- set result for every process |
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maxPhi = phiGMR8(1,0) |
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|
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RETURN |
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END |
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