Hi, I am trying to use the function sread() but when I run the matlab program it give me this error:
-One or more output arguments not assigned during call to "sread". and nothing happen... I also tried to use sreader but matlab didn't respond, am I doing something wrong? I am using Matlab R2008a, which matlab version is the most compatible with Petsc? Thank you, Michel On Mon, Jul 28, 2008 at 8:45 PM, Barry Smith <bsmith at mcs.anl.gov> wrote: > > On Jul 28, 2008, at 12:33 PM, Michel Cancelliere wrote: > > Hi, >> Thank you for your response, I think the socket communication between >> Matlab and PETSc is what I need, I took a look to the example ex12.c and >> ex12.m (Simple example to show how to PETSc programs can be run from Matlab) >> but in this case PETSc send the Vector solution that matlab "receive", is it >> possible to make the inverse? Send the variable from matlab to PETSc using >> socket communication? can PetscMatlabEngineGet do that ? How it works? >> > > You don't really want to use the Matlab Engine code, because with this > approach the PETSc program is "in charge" and just sends work requests > to Matlab. Instead you want Matlab in charge and to send work requests to > PETSc. > > The basic idea is that both Matlab and PETSc open a socket connection to > each other. On the PETSc side use PetscViewerSocketOpen() on the Matlab side > use the bin/matlab/@sreader/sreader.m class to create a (Matlab) socket > object. Now on the PETSc side you can make calls to VecView() to send > vectors to > Matlab and VecLoad() and MatLoad() to read vectors and matrices from > Matlab. On the Matlab side use PetscBinaryRead() and PetscBinaryWrite() to > read vectors from PETSc and to write vectors and matrices to PETSc. Your > PETSc program may end up looking something like > > PetscViewerSocketOpen(..... &socket); > > do forever: > VecLoad(socket, &b) > MatLoad(socket,....,&A) > > KSPSetOperators(ksp,A,A,....) > KSPSolve(ksp,b,x) > VecView(socket,x) > > You Matlab program could look something like > > socket = sread() > > do forever: > > Create your vector and matrix > PetscBinaryWrite(socket,b) > PetscBinaryWrite(socket,A) > x = PetscBinaryRead(socket) > > The details and correct syntax are obviously not given. > > Good luck, > > Barry > > > >> >> Aron, I was studying your recommendation but it means that I have to write >> all the function from my Matlab Code to C?, because it should take me a lot >> of time and this work is part of my MSc Thesis and maybe I need a less time >> consuming solution. >> >> Thank you in advance, >> >> Michel >> >> On Tue, Jul 22, 2008 at 8:56 PM, Aron Ahmadia <aja2111 at columbia.edu> >> wrote: >> Michel, >> >> I would recommend investing the time to write your C/C++ wrapper code a >> little higher up around the Newton iteration, since PETSc provides a great >> abstraction interface for it. Then you could write code to build the matrix >> (or assemble a matrix-free routine!) in C/C++, and pass the parameters in >> from there. >> >> ~Aron >> >> >> On Tue, Jul 22, 2008 at 12:12 AM, Matthew Knepley <knepley at gmail.com> >> wrote: >> On Mon, Jul 21, 2008 at 10:14 PM, Barry Smith <bsmith at mcs.anl.gov> wrote: >> > >> > On Jul 21, 2008, at 7:57 PM, Michel Cancelliere wrote: >> > >> >> Hi, I am a new user of PETSc. I am working in Reservoir Simulation and >> I >> >> have been developing the simulator inside Matlab. I have some question >> in >> >> order to understand better my possibilities of success in what I want >> to do: >> >> >> >> ? I want to solve the linear system obtained from the inner >> >> iterations in the newton method using PETSc, is it possible to >> communicate >> >> in an efficient way PETSc with Matlab to do that? I now that I can >> write >> >> binary files and then read with PETSc but due the size of the matrix it >> is a >> >> very time-expensive way. Where i can find some examples? I look at the >> >> examples within the package but I could not find it. \ >> >> ? It is possible to call PETSc library inside Matlab? Using the >> Mex >> >> files and Matlab compiler? >> > >> > There is no code to do this. It is possible but pretty complicated to >> > write the appropriate Mex code. (Because >> > each Mex function is a separate shared library you cannot just write a >> Mex >> > function for each PETSc function since they >> > would not share the PETSc global variables. You would have to write one >> Mex >> > function that is a "gatekeeper" and calls >> > the requested PETSc function underneath. I've monkeyed with this a few >> times >> > but did not have the time/energy/intellect >> > to write code to automate this process. Give me 300,000 dollars and we >> could >> > hire someone to write this :-) >> > >> > You might look at the "newly improved" socket interface in petsc-dev >> > (http://www-unix.mcs.anl.gov/petsc/petsc-as/developers/index.html). >> > With this you write a stand alone C PETSc program that waits at a >> socket, >> > receive the matrix and right hand side and then >> > sends back the solution. The code for marshalling the matrices and >> vector is >> > common between the sockets and binary files. >> > On the Matlab side you create a "file" that is actually a socket >> connection. >> > See src/sys/viewer/impls/socket/matlab This may >> > take a little poking around and you asking us a couple of questions to >> get >> > it. >> > Note there is no inherent support for parallelism on the PETSc side with >> > this setup but I think it is possible. >> >> I personally think this would be much easier in Sage than in Matlab >> proper. In fact, >> with Sage you could use petsc4py directly, and directly access the >> data structures >> as numpy arrays if necessary. >> >> Matt >> >> > Barry >> > >> > >> >> Thank you very much for your time, >> >> >> >> Michel Cancelliere >> > >> > >> >> >> >> -- >> What most experimenters take for granted before they begin their >> experiments is infinitely more interesting than any results to which >> their experiments lead. >> -- Norbert Wiener >> >> >> >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20080808/8472b329/attachment.htm>
