MPIFilereadatallCollective read using explicit offsetSynopsisint MPIFilereadatall(MPIFile fh, MPIOffset offset, void.buf,int count, MPIDatatype datatype,MPIStatus.status)Input Parameters fh file handle (handle)offset file offset (nonnegative integer)count number of elements in buffer (nonnegative integer)datatype datatype of each buffer element (handle)Output Parameters buf initial address of buffer (choice)status status object (Status)Notes for FortranAll MPI routines in Fortran (except for MPIWTIME and MPIWTICK) havean additional argument ierr at the end of the argument list. Ierris an integer and has the same meaning as the return value of the routinein C. In Fortran, MPI routines are subroutines, and are invoked with thecall statement.All MPI objects (e.g., MPIDatatype, MPIComm) are of type INTEGERin Fortran.Location:mpi-io/readatall.c.
Hi all,I already have used mpi4py extensively. However, I have not yet usedthe parallel IO functions. I am writing a new program where parallelIO is required. Does anyone have some simple examples of MPI2 IO usingmpi4py?
I run into trouble almost straight away. Principally because Ido not know what the 'cls' object is (see below).def Open(cls, Intracomm comm not None, filename,int amode=MODERDONLY, Info info=INFONULL):'Open a file'cdef char.cfilename = NULLfilename = asmpistr(filename, &cfilename, NULL)cdef MPIInfo cinfo = argInfo(info)cdef File file = clswith nogil: CHKERR( MPIFileopen(comm.obmpi, cfilename, amode, cinfo, &file.obmpi) )return fileChris ButlerLisandro Dalcin14.09.10 21:23. On 15 September 2010 00:43, chrisb wrote: Hi all, I already have used mpi4py extensively.
Mpi Fgets
However, I have not yet used the parallel IO functions. I am writing a new program where parallel IO is required. Does anyone have some simple examples of MPI2 IO using mpi4py?I've never used MPI I/O extensively. However, if you can elaborate abit more on your needs, I could provide some examples (and get a bitof motivation for adding a demo). How does your data to read/writelooks? I run into trouble almost straight away.
Principally because I do not know what the 'cls' object is (see below). def Open(cls, Intracomm comm not None, filename, int amode=MODERDONLY, Info info=INFONULL): ' Open a file ' cdef char.cfilename = NULL filename = asmpistr(filename, &cfilename, NULL) cdef MPIInfo cinfo = argInfo(info) cdef File file = cls with nogil: CHKERR( MPIFileopen( comm.obmpi, cfilename, amode, cinfo, &file.obmpi) ) return file Chris ButlerDid you missed the @classmethod right above the 'def Open(.)'? Haveyou ever seen/coded a classmethod in Python? This is the official docabout it:,you can also use help(classmethod) in your Python prompt. FYI, Openis implemented as a classmethod for two reasons: (1) the way to callit is similar to C, mpi4py's API is quite similar to C bindings,and (2) It helps a little with inheritance if you want to subclass theFile class, the line 'cdef File file = cls' means that if'cls' is a subclass, the created file will verify 'type(file) is cls'i.e. The subclass, and not 'type(file) is MPI.File' i.e de base class.After all that previous uninteresting stuff, you have to open files like this:myfile = MPI.File.Open(comm, filename, mode)Remember a fresly-opened file is prepared to read/write bytes; youhave to file.Setview if you plan to write types data, let sayintegers or floating point array data.-Lisandro Dalcin-CIMEC (INTEC/CONICET-UNL)Predio CONICET-Santa FeColectora RN 168 Km 472, Paraje El PozoTel: +54-3 (ext 1011)Tel/Fax: +54-3chrisb14.09.10 21:58. Hi Lisandro,Thank you for your fast reply.I had not previously seen class methods coded in python and ty for theexplainer.
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I think the roots of my troubles is an error which occurredon OS X. I successfully ran the following code on a linux box,however, OS X (10.6 with OpenMPI 1.4.1) gives the following: butler$ pythonPython 2.6.1 (r261:67515, Feb 11 2010, 15:47:53)GCC 4.2.1 (Apple Inc. Build 5646) on darwinType 'help', 'copyright', 'credits' or 'license' for more information.
import mpi4py.MPI as MPI filehandle = MPI.File.Open(MPI.COMMWORLD, 'test.plt',MPI.MODERDONLY)Traceback (most recent call last):File ', line 1, in File 'File.pyx', line 67, in mpi4py.MPI.File.Open (src/mpi4py.MPI.c:68245)mpi4py.MPI.Exception: MPIERROTHER: known error not in listI may have to try a newer version of OpenMPI to get it working underOS X.Chris ButlerOn Sep 15, 2:23 pm, Lisandro Dalcin wrote:Russel15.09.10 0:45. On Tue, 2010-09-14 at 21:58 -0700, chrisb wrote: butler$ python Python 2.6.1 (r261:67515, Feb 11 2010, 15:47:53) GCC 4.2.1 (Apple Inc. Chris,On Wed, 2010-09-15 at 03:58 -0700, chrisb wrote: I hope I am not pointing out the obvious.
But do you have a 'test.plt' file in your current working directory? The MPI.MODERDONLY is specifying a read only mode. You had an MPI file existence error.Challenging the obvious is always a good move. I thought I had createdthat file, but clearly I had not. Creating the file means the lineworks fine for me on both Ubuntu and Mac OS X.
I am using the Pythonand OpenMPI from MacPorts.Ubuntu: pythonPython 2.6.5 (r265:79063, Apr 16 2010, 13:57:41)GCC 4.4.3 on linux2Type 'help', 'copyright', 'credits' or 'license' for more information. import mpi4py.MPI as MPI filehandle = MPI.File.Open(MPI.COMMWORLD, 'test.plt',MPI.MODERDONLY)KeyboardInterrupt.
An error occurred in MPIBarrier. after MPI was finalized. MPIERRORSAREFATAL (your MPI job will now abort)Mac OS X: pythonPython 2.6.6 (r266:84292, Aug 27 2010, 11:30:11)GCC 4.2.1 (Apple Inc.
C File Read Example
Build 5664) on darwinType 'help', 'copyright', 'credits' or 'license' for more information. import mpi4py.MPI as MPI filehandle = MPI.File.Open(MPI.COMMWORLD, 'test.plt',MPI.MODERDONLY). The MPIBarrier function was called after MPIFINALIZE was invoked.
Mpi Gather Example
This is disallowed by the MPI standard. Your MPI job will now abort.-Russel.Dr Russel Winder t: + 2200 voip:41 Buckmaster Road m: +44 7770 465 077 xmpp:London SW11 1EN, UK w: skype: russelwinderLisandro Dalcin15.09.10 7:23. On Wed, 2010-09-15 at 11:23 -0300, Lisandro Dalcin wrote:.
python Python 2.6.6 (r266:84292, Aug 27 2010, 11:30:11) GCC 4.2.1 (Apple Inc. Hi,I just updated (using MacPorts in MacOS 10.5.8) my python toversion 2.6.6, my mpi4pi to py26-mpi4y, and openMPI to version 1.4.2.Maybe a mistake to do it all at once!
My C MPI programs seem still tobe OK, but my python MPI scripts now seem to be badly broken.Specifically, the MPI.COMMSELF.Spawn command fails spectacularly. Apython script, which launches some worker tasks and sets up a dialogwith them, and the output when it runs, are attached.The script is unchanged since before the updates, when it workedperfectly. Any suggestions?Steve McMillan-Stephen L. McMillan, Professor of Physics, Drexel University+1 215-895-2723, FAX +1 215-895-1549,Arjen van Elteren21.09.10 10:45. Hi,I've seen problems like these when the worker code was out of sync.So maybe rebuilding the nbodywork will help.Also all mpi frameworks cannot talk together when the versions ortypes are different (I've got mpirun and mpicxxand openmpicxx and openmpirun and these definitely don't mix)Arjen - You received this message because you are subscribed to the Google Groups 'mpi4py' group.
To post to this group, send email to. To unsubscribe from this group, send email to. For more options, visit this group at. steve21.09.10 10:51.