Hi Cristobal,
Note that the pic in http://dl.dropbox.com/u/6380744/clusterLibs.png
shows that Scalapack is based on what; it only shows which packages
Scalapack uses; hence no OpenMP is there.
Also be clear about the difference:
"OpenMP" is for shared memory parallel programming, while
"OpenMPI"
y model locally at each node, evading unnecesary I/O through the
> nwetwork, what do you think?
>
>
>
> On Thu, Jul 22, 2010 at 5:27 PM, amjad ali wrote:
> > Hi Cristobal,
> >
> > Note that the pic in http://dl.dropbox.com/u/6380744/clusterLibs.png
> > shows t
Perhaps often it is more useful to use MPI_WAIT rather than MPI_TEST type
fucntions, because at MPI_WAIT point it will be taken care of communication
completion, automatically, which may be necessary before going ahead. with
MPI_TEST it would become the responsibility of the programmer to handle th
which one to use MTL or
BTL?
Thank you.
Regards,
Amjad Ali
justifying this and comment/modify above two
justifications. Better if I you can suggent me to quote some reference of
any suitable publication in this regard.
best regards,
Amjad Ali
Thanking you all very much for the reply.
I would request to have some reference about what Tim Prince & Andreas has
said.
Tim said that OpenMPI has had effective shared memory message passing. Is
that anything to do with --enable-MPI-threads switch while installing
OpeMPI?
regards,
AA
KIND ATTENTION.
With best regards,
Amjad Ali.
On Fri, Aug 14, 2009 at 1:32 AM, Eugene Loh wrote:
> amjad ali wrote:
>
> I am parallelizing a CFD 2D code in FORTRAN+OPENMPI. Suppose that the grid
> (all triangles) is partitioned among 8 processes using METIS. Each process
> has different number of neighboring processes. Suppo
Hello Mr. Eugene Loh,
THANK YOU VERY MUCH, IT WORKED. I used both ISEND and IRECV and then a
combined call to WAITALL with MPI_STATUSES_IGNORE.
with best regards,
Amjad Ali.
On Fri, Aug 14, 2009 at 6:42 AM, Eugene Loh wrote:
> amjad ali wrote:
>
> Please tell me that if have mult
different location than
the ./sphere.
Openmpi is installed with GNU compilers.
Best Regards,
Amjad Ali
ils on your
> installation, your system and your shell.
>
> Greetings, Jakob
>
My installation is ROCKS-5 (64 bit), 4-nodes with Xeon3085, bash shell.
Compilers are GNU 64-bit.
Next??
>
> amjad ali wrote:
> > Hi all,
> > A simple program at my 4-node ROCKS cluster
Hi all,
I want to get the elapsed time from start to end of my parallel program
(OPENMPI based). It should give same time for the same problem always;
irrespective of whether the nodes are running some or programs or they are
running only that program. How to do this?
Regards.
Hi all,
I need/request some help from those who have some experience in
debugging/profiling/tuning parallel scientific codes, specially for
PDEs/CFD.
I have parallelized a Fortran CFD code to run on
Ethernet-based-Linux-Cluster. Regarding MPI communication what I do is that:
Suppose that the gri
; T. Rosmond
>
>
>
> On Fri, 2009-11-06 at 17:44 -0500, amjad ali wrote:
> > Hi all,
> >
> > I need/request some help from those who have some experience in
> > debugging/profiling/tuning parallel scientific codes, specially for
> > PDEs/CFD.
> >
>
/portion in the recv_array.
Is this scheme is quite fine and correct.
I am in search of efficient one.
Request for help.
With best regards,
Amjad Ali.
benefit/efficiency?
Better if any body can refer to some tutorial/example-code on this.
Thank you for you attention.
With best regards,
Amjad Ali.
s (10, 20 or 30 may be) in the header
while making call to a subroutine.
Which way is quite fast and efficient over the other?
Thank You for your kind attention.
with best regards,
Amjad Ali.
Hi,
Suppose we run a parallel MPI code with 64 processes on a cluster, say of 16
nodes. The cluster nodes has multicore CPU say 4 cores on each node.
Now all the 64 cores on the cluster running a process. Program is SPMD,
means all processes has the same workload.
Now if we had done auto-vectoriz
Hi,
thanks T.Prince,
Your saying:
"I'll just mention that we are well into the era of 3 levels of programming
parallelization: vectorization, threaded parallel (e.g. OpenMP), and
process parallel (e.g. MPI)." is a really great new learning for me. Now I
can perceive better.
Can you please expl
Dear Hammad,
Can you please have a RUN with "sufficiently Larger Problem Instance"? Then
see what happens!!
Sufficientmay be 10 times greater than that you used.
best regards,
Amjad Ali.
On Fri, Mar 12, 2010 at 3:10 AM, Hammad Siddiqi wrote:
> Dear All,
> Is this the c
Hi all,
I observed MPI_ISEND & IRECV performing little better than persistenent
communication; although I was hoping/desiring the opposite case??
What is the be the best way of using MPI persistent communication in an
iterative/repetative kind of code about calling MPI_Free(); Should we call
MPI
Hi Jeff S.
Thank you very much for your reply.
I am still feeling some confusion. Please guide.
The idea is to do this:
>
>MPI_Recv_init()
>MPI_Send_init()
>for (i = 0; i < 1000; ++i) {
>MPI_Startall()
>/* do whatever */
>MPI_Waitall()
>}
>for (i = 0;
>
> You would break the MPI_Irecv and MPI_Isend calls up into two parts:
> MPI_Send_init and MPI_Recv_init in the first part and MPI_Start[all] in the
> second part. The first part needs to be moved out of the subroutine... at
> least outside of the loop in sub1() and maybe even outside the
> 1000
Dear E. Loh.
**
>
>
> Another is whether you can overlap communications and computation. This
> does not require persistent channels, but only nonblocking communications
> (MPI_Isend/MPI_Irecv). Again, there are no MPI guarantees here, so you may
> have to break your computation up and insert MP
I guess that if the receiver want to ensure that the sender should send data
only when the receiver will be able/free to receive data,
then use MPI-Barriers.
On Mon, Jun 28, 2010 at 12:53 PM, David Zhang wrote:
> Use MPI_Iprobe. It's a nonblocking probe that allow you to see if a
> message i
and it's conceivable that you might have better performance with
>
> CALL MPI_ISEND()
> DO I = 1, N
> call do_a_little_of_my_work() ! no MPI progress is being made here
> CALL MPI_TEST()! enough MPI progress is being made here
> that the receiver has something t
Dear E. loh,
Thank u very much for your help.
Actually i was doing the same according to your earlier suggestions
---and now in the program; but error was there.
At last i found the blunder made by myself.
It was a typo mistake infact of a variable name.
i will let u know about the performan
Based on my experiences, I would FULLY endorse (100% agree with) David
Zhang.
It is usually a coding or typo mistake.
At first, Ensure that array sizes and dimension are correct.
I experience that if openmpi is compiled with gnu compilers (not with Intel)
then it also point outs the subroutine ex
from the start of your program, after a certain activitiy, say after 10
lines use print statement with STOP/EXIT , also printing processor rank.
If u get all the processors than its fine. Move this printing little ahead
and get printing again. Repeat this process until u reach the place of
fault.
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