| 1 | 
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| 2 | /** \page group The Group Library
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| 3 | 
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| 4 | The group library provides three mechanisms for parallel execution and
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| 5 | communication.  These are:
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| 6 | 
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| 7 | <ul>
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| 8 |   <li> \ref messagepassing
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| 9 |   <li> \ref distmemory
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| 10 |   <li> \ref multithreading
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| 11 | </ul>
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| 12 | 
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| 13 | \section messagepassing Message Passing
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| 14 | 
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| 15 | The MessageGrp class is the ancestor for classes that provide the passing
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| 16 | of messages between processes.  There are three important specializations
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| 17 | of this class:
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| 18 | 
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| 19 | <dl>
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| 20 | 
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| 21 |   <dt>ProcMessageGrp<dd>Provides a dummy MessageGrp for single processor
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| 22 |                         case.
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| 23 | 
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| 24 |   <dt>MPIMessageGrp<dd>Implements MessageGrp using the Message Passing
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| 25 |                        Interface (MPI) library.
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| 26 | 
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| 27 |   <dt>ShmMessageGrp<dd>Implements MessageGrp using SysV Interprocess
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| 28 |                        communication.
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| 29 | 
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| 30 | </dl>
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| 31 | 
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| 32 | Due to the widespread acceptance of MPI and the large number of features
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| 33 | that it supports, the MessageGrp specialization may one day be eliminated.
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| 34 | 
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| 35 | \section distmemory Distributed Shared Memory
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| 36 | 
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| 37 | The MemoryGrp class is the ancestor for classes that permit access to the
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| 38 | memory in different processes, possible on difference machines.  There are
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| 39 | two important specializations of this class:
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| 40 | 
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| 41 | <dl>
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| 42 | 
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| 43 |   <dt>ProcMemoryGrp<dd>Provides a dummy MemoryGrp for single processor
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| 44 |                        case.
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| 45 | 
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| 46 |   <dt>MTMPIMemoryGrp<dd> This works reliably and efficiently, however,
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| 47 |                          requires POSIX threads and a thread-safe MPI
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| 48 |                          implementation.
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| 49 | 
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| 50 |   <dt>ARMCIMemoryGrp<dd> This message group uses the Aggregate Remote Copy
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| 51 |                          Interface (ARMCI).  This exploits the RDMA
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| 52 |                          capabilities of interconnects such as Myrinet and
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| 53 |                          InfiniBand.
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| 54 | 
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| 55 | 
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| 56 | </dl>
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| 57 | 
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| 58 | \section multithreading Multi-Threading
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| 59 | 
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| 60 | The ThreadGrp class is the ancestor of classes that provide
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| 61 | multiple-threads within a single address space.  There are
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| 62 | two important specializations of this class:
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| 63 | 
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| 64 | <dl>
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| 65 | 
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| 66 |   <dt>ProcThreadGrp<dd>Provides a dummy ThreadGrp for the single thread
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| 67 |                        case.
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| 68 | 
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| 69 |   <dt>PthreadThreadGrp<dd> This is a ThreadGrp that uses POSIX threads.
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| 70 | 
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| 71 | </dl>
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| 72 | 
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| 73 | 
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| 74 | */
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