Re: Ada-friendly MPI

[jtg <jtg77@poczta.onet.pl>]

Pascal Obry wrote:
> jtg <jtg77@poczta.onet.pl> writes:
> 
> 
>>As far as I am concerned Ada Distributed Annex is non-standard. :-(
> 
> 
> Depending on what you mean by standard. Ada 95 is an ISO standard and the
> distributed annex is part of it :)
> 
So it's a pun: a standard that is not standard :-)
(An ISO standard that is not standard feature in supercomputer environments)

> 
>>All three supercomputers, that I had opportunity to use, supported MPI
> 
> 
> What are you supercomputers ? Is that a cluster ?
> 
1. Cluster 15 x  POWER2 RS/6000
2. Cluster 128 x PIII Xeon
3. I don't remember.
But all that was several years ago :-)

> 
> I've used it myself for experimentation on Windows, GNU/Linux and Solaris.
> 
> If your supercomputers is running GNU/Linux I don't see why this won't be
> working. What compiler are you using ?
> 
In supercomputer environment many problems arise when you want to use Ada.
There are very fast communication links between processors and MPI libraries
are especially optimized for hardware. You should have Ada libraries for
the hardware and I haven't seen any such library even mentioned.
Another problem is infrastructure. You need libraries, you need running host
processes at every node (for starting your subtasks), you need task spooling
system etc. You need proper configuration. But everything is suited for MPI.
For example: When you put your parallel task on queue, the spooler automatically
starts subtasks on some nodes as they become available,
establishes MPI communication between them and assigns MPI number to every
subtask. Now, how to begin computations using Ada built-in parallelism?
I don't even know how to establish Ada-style communication between them.
And all the problems vanish when you use simple C binding for MPI library...