Re: [OMPI users] speed up this problem by MPI

On Fri, 29 Jan 2010 11:25:09 -0500, Richard Treumann wrote: > Any support for automatic serialization of C++ objects would need to be in > some sophisticated utility that is not part of MPI. There may be such > utilities but I do not think anyone who has been involved in

Re: [OMPI users] speed up this problem by MPI

Tim wrote: By serialization, I mean in the context of data storage and transmission. See http://en.wikipedia.org/wiki/Serialization e.g. in a structure or class, if there is a pointer pointing to some memory outside the structure or class, one has to send the content of the memory besides

Re: [OMPI users] speed up this problem by MPI

29/2010 11:11 AM Subject: Re: [OMPI users] speed up thi

Re: [OMPI users] speed up this problem by MPI

or class, right? --- On Fri, 1/29/10, Eugene Loh <eugene@sun.com> wrote: > From: Eugene Loh <eugene@sun.com> > Subject: Re: [OMPI users] speed up this problem by MPI > To: "Open MPI Users" <us...@open-mpi.org> > Date: Friday, January 29, 2010, 11:06

Re: [OMPI users] speed up this problem by MPI

Tim wrote: Sorry, my typo. I meant to say OpenMPI documentation. Okay. "Open (space) MPI" is simply an implementation of the MPI standard -- e.g., http://www.mpi-forum.org/docs/mpi21-report.pdf . I imagine an on-line search will turn up a variety of tutorials and explanations of that

Re: [OMPI users] speed up this problem by MPI

with serialization problems? Are there some good reference for these problems? --- On Fri, 1/29/10, Eugene Loh <eugene@sun.com> wrote: > From: Eugene Loh <eugene@sun.com> > Subject: Re: [OMPI users] speed up this problem by MPI > To: "Open MPI Users" <

Re: [OMPI users] speed up this problem by MPI

Tim wrote: BTW: I would like to find some official documentation of OpenMP, but there seems none? OpenMP (a multithreading specification) has "nothing" to do with Open MPI (an implementation of MPI, a message-passing specification). Assuming you meant OpenMP, try their web site:

Re: [OMPI users] speed up this problem by MPI

> From: Eugene Loh <eugene@sun.com> > Subject: Re: [OMPI users] speed up this problem by MPI > To: "Open MPI Users" <us...@open-mpi.org> > Date: Friday, January 29, 2010, 12:50 AM > Tim wrote: > > > Sorry, complicated_computation() and f() are > si

Re: [OMPI users] speed up this problem by MPI

Tim wrote: Sorry, complicated_computation() and f() are simplified too much. They do take more inputs. Among the inputs to complicated_computation(), some is passed from the main() to f() by address since it is a big array, some is passed by value, some are created inside f() before the call

Re: [OMPI users] speed up this problem by MPI

[i], feature); // > time consuming > } > // some operations using all elements in array > delete [] array; > } > > --- On Thu, 1/28/10, Eugene Loh <eugene@sun.com> wrote: > > > From: Eugene Loh <eugene@su

Re: [OMPI users] speed up this problem by MPI

} --- On Thu, 1/28/10, Eugene Loh <eugene@sun.com> wrote: > From: Eugene Loh <eugene@sun.com> > Subject: Re: [OMPI users] speed up this problem by MPI > To: "Open MPI Users" <us...@open-mpi.org> > Date: Thursday, January 28, 2010, 11:40 PM >

Re: [OMPI users] speed up this problem by MPI

Tim wrote: Thanks Eugene! My case, after simplified, is to speed up the time-consuming computation in the loop below by assigning iterations to several nodes in a cluster by MPI. Each iteration of the loop computes each element of an array. The computation of each element is independent of

Re: [OMPI users] speed up this problem by MPI

Hi Tim Your OpenMP layout suggests that there are no data dependencies in your "complicated_computation()" and the operations therein are local. I will assume this is true in what I suggest. In MPI you could use MPI_Scatter to distribute the (initial) array values before the computational loop,

Re: [OMPI users] speed up this problem by MPI

ene Loh <eugene@sun.com> wrote: > From: Eugene Loh <eugene@sun.com> > Subject: Re: [OMPI users] speed up this problem by MPI > To: "Open MPI Users" <us...@open-mpi.org> > Date: Thursday, January 28, 2010, 8:31 PM > Tim wrote: > > &g

Re: [OMPI users] speed up this problem by MPI

On Thu, 2010-01-28 at 17:05 -0800, Tim wrote: > Also I only need the loop that computes every element of the array to > be parallelized. Someone said that the parallel part begins with > MPI_Init and ends with MPI_Finilize, and one can do any serial > computations before and/or after these calls.

Re: [OMPI users] speed up this problem by MPI

in(). > > If someone could give a sample of how to apply MPI in my case, it will > clarify a lot of my questions. Usually I can learn a lot from good examples. > > Thanks! > > --- On Thu, 1/28/10, Eugene Loh <eugene....@sun.com> wrote: > > > From: Eugene Loh <eu

Re: [OMPI users] speed up this problem by MPI

Tim wrote: Thanks, Eugene. I admit I am not that smart to understand well how to use MPI, but I did read some basic materials about it and understand how some simple problems are solved by MPI. But dealing with an array in my case, I am not certain about how to apply MPI to it. Are you

Re: [OMPI users] speed up this problem by MPI

. Usually I can learn a lot from good examples. Thanks! --- On Thu, 1/28/10, Eugene Loh <eugene@sun.com> wrote: > From: Eugene Loh <eugene@sun.com> > Subject: Re: [OMPI users] speed up this problem by MPI > To: "Open MPI Users" <us...@open-mpi.org> > D

Re: [OMPI users] speed up this problem by MPI

Take a look at some introductory MPI materials to learn how to use MPI and what it's about. There should be resources on-line... take a look around. The main idea is that you would have many processes, each process would have part of the array. Thereafter, if a process needs data or results

[OMPI users] speed up this problem by MPI

Hi, (1). I am wondering how I can speed up the time-consuming computation in the loop of my code below using MPI? int main(int argc, char ** argv) { // some operations f(size); // some operations return 0; }