MPI_SCATTER Fortran Matrices by Rows

Posted by Fortran on Stack Overflow See other posts from Stack Overflow or by Fortran
Published on 2010-03-22T21:14:20Z Indexed on 2010/03/22 21:21 UTC
Read the original article Hit count: 610

Filed under:

fortran

|

fortran90

|

mpi

What is the best way to scatter a Fortran 90 matrix by its rows rather than columns? That is, let's say I have a matrix a(4,50) and I want to MPI_SCATTER it onto two processes where each part is alocal(2,50), where rank 0 has rows 1 and 2, and rank 1 has 3 and 4. Now, in C, this is simple since arrays are row-major, but in Fortran 90 they are column-major.

I'm trying to avoid using TRANSPOSE to flip a before scattering (i.e, doubling the memory use), and I figure there must be a way in MPI to do this. Would it be MPI_TYPE_VECTOR? MPI_TYPE_CREATE_SUBARRAY?

Likewise, what if I have a 3d array b(4,50,3) and I want two scattered matrices of blocal(2,50,3) distributed as above?

© Stack Overflow or respective owner

Related posts about fortran

passing a fortran int array to C++ by calling C++ function in fortran

as seen on Stack Overflow - Search for 'Stack Overflow'
hi, I am trying to call a C++ function in FORTRAN subroutine. This C+ function is supposed to update an integer array. Here is a non-working code I wrote. Can someone please let me know what the issue is: ! FORTRAN function that calls a C++ function subroutine my_function() integer(4) ar(*) … >>> More
MinGW/G++/g95 link problem - libf95 undefined reference to `MAIN_'

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi folks, Summing up, my problem consists on compiling g95 objects inside a C++ application. Actually, I'm constructing an interface for an old fortran program. For this task, I'm using the wxWidgets GUI library, and calling fortran subroutines when necessary. At the beginning, I was developing the… >>> More
Fortran arrays and subroutines

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm going through a Fortran code, and one bit has me a little puzzled. There is a subroutine, say SUBROUTINE SSUB(X,...) REAL*8 X(0:N1,1:N2,0:N3-1),... ... RETURN END Which is called in another subroutine by: CALL SSUB(W(0,1,0,1),...) where W is a 'working array'. It appears that a specific… >>> More
fortran 90 user defined type, passing by value ?

as seen on Stack Overflow - Search for 'Stack Overflow'
I have an issue in fortran 90. I have a user defined type and when I call one of the MPI subroutines the data looks to be passed by values (not address, as I thought it should). The output arguments aren't modified. It seems to be specific to the MPI calls I tried the same thing in a simple test… >>> More
Should External Routine Be Declared Always in Fortran?

as seen on Stack Overflow - Search for 'Stack Overflow'
In my fortran code I made the following call to dnrm2 routine d = dnrm2(n, ax, 1) Just a simple call that would return me a double precision result. The problem is whether I should declare the function at the start of my script. I found that if I don't declare it, and when I compile the code in… >>> More

Related posts about fortran90

Debugging fortran code in Eclipse with Photran and GDB debugger: missing symbols

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a program, written in fortran90, previously successfully compiled on a compaq compiler and working, that I'm now trying to compile with gfortran. I can compile the code to an .exe and run it. It works fine until a certain point in the routine and then an error is thrown. My current configuration: Windows… >>> More
fortran 90 user defined type, passing by value ?

as seen on Stack Overflow - Search for 'Stack Overflow'
I have an issue in fortran 90. I have a user defined type and when I call one of the MPI subroutines the data looks to be passed by values (not address, as I thought it should). The output arguments aren't modified. It seems to be specific to the MPI calls I tried the same thing in a simple test… >>> More
MPI_SCATTER Fortran Matrices by Rows

as seen on Stack Overflow - Search for 'Stack Overflow'
What is the best way to scatter a Fortran 90 matrix by its rows rather than columns? That is, let's say I have a matrix a(4,50) and I want to MPI_SCATTER it onto two processes where each part is alocal(2,50), where rank 0 has rows 1 and 2, and rank 1 has 3 and 4. Now, in C, this is simple since arrays… >>> More
fortran SAVE statement

as seen on Stack Overflow - Search for 'Stack Overflow'
I've read it's entry in the language reference (Intel's), but I cannot quite grasp what it does. Could someone in layman's terms explain it to me, what it means when it is included in a module ? >>> More
catching a deadlock in a simple odd-even sending

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm trying to solve a simple problem with MPI, my implementation is MPICH2 and my code is in fortran. I have used the blocking send and receive, the idea is so simple but when I run it it crashes!!! I have absolutely no idea what is wrong? can anyone make quote on this issue please? there is a piece… >>> More