OpenMP in Fortran

Posted by user345293 on Stack Overflow See other posts from Stack Overflow or by user345293
Published on 2010-05-19T16:56:51Z Indexed on 2010/05/19 17:00 UTC
Read the original article Hit count: 236

Filed under:

fortran

|

openmp

I very rarely use fortran, however I have been tasked with taking legacy code rewriting it to run in parallel. I'm using gfortran for my compiler choice. I found some excellent resources at https://computing.llnl.gov/tutorials/openMP/ as well as a few others.

My problem is this, before I add any OpenMP directives, if I simply compile the legacy program:

gfortran Example1.F90 -o Example1

everything works, but turning on the openmp compiler option even without adding directives:

gfortran -openmp Example1.F90 -o Example1

ends up with a Segmentation fault when I run the legacy program. Using smaller test programs that I wrote, I've successfully compiled other programs with -openmp that run on multiple threads, but I'm rather at a loss why enabling the option alone and no directives is resulting in a seg fault.

I apologize if my question is rather simple. I could post code but it is rather long. It faults as I assign initial values:

    REAL, DIMENSION(da,da) :: uconsold
    REAL, DIMENSION(da,da,dr,dk) :: uconsolde

    ...

    uconsold=0.0    
    uconsolde=0.0

The first assignment to "uconsold" works fine, the second seems to be the source of the fault as when I comment the line out the next several lines execute merrily until "uconsolde" is used again.

Thank you for any help in this matter.

© 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 openmp

Can I implement the readers and writers algorithm in OpenMP by replacing counting semaphores with another feature?

as seen on Programmers - Search for 'Programmers'
After reading about OpenMP and not finding functions to support semaphores, I did an internet search for OpenMP and the readers and writers problem, but found no suitable matches. Is there a general method for replacing counting semaphores in OpenMP with something that it supports? Or is there just… >>> More
Iteration through std containers in openmp

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, people. I try to use openmp for multithreading the loop through std::set. When I write the following code - #pragma omp parallel for for (std::set<A>::const_iterator i = s.begin(); i != s.end(); ++i) { const A a = *i; operate(a); } I get an error -… >>> More
Controlling FPU behavior in an OpenMP program?

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a large C++ program that modifies the FPU control word (using _controlfp()). It unmasks some FPU exceptions and installs a SEHTranslator to produce typed C++ exceptions. I am using VC++ 9.0. I would like to use OpenMP (v.2.0) to parallelize some of our computational loops. I've already… >>> More
Segmentation fault on MPI, runs properly on OpenMP

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am trying to run a program on a computer cluster. The structure of the program is the following: PROGRAM something ... CALL subroutine1(...) ... END PROGRAM SUBROUTINE subroutine1(...) ... DO i=1,n CALL subroutine2(...) ENDDO ... END SUBROUTINE SUBROUTINE subroutine2(...) ... CALL subroutine3(… >>> More
Segmentation fault while matrix multiplication using openMp?

as seen on Stack Overflow - Search for 'Stack Overflow'
My matrix multiplication code is int matMul(int ld, double** matrix) { //local variables initialize omp_set_num_threads(nthreads); #pragma omp parallel private(tid,diag,ld) shared(i,j,k,matrix) { /* Obtain and print thread id */ tid = omp_get_thread_num(); for ( k=0; k<ld; k++) … >>> More