[deal.II] openmp flag in CMake?

[Kartik Jujare]

Hello,

Would be grateful if anyone could correct or direct me to the right
solution.

As a test I have a following for loop is a step file

#pragma omp parallel
{
#pragma omp for //private(k) reduction(+:integral)
for (k = 0; k < 4; k++)
{
sleep(1);
}
}


Now the time outputs of the this for loop and another normal one (without
openmp) are the same. I think the problem lies in the flag that I am
passing in the Cmakefile but cant figure out what?

I have tried setting the following flags:

SET (MPI_CXX_COMPILE_FLAGS "-fopenmp")
//OR
SET (DEAL_II_CXX_FLAGS "-fopenmp")

I suppose I dont understand cmake very well. What would be an appropriate
place to place the above line in the CMakeLists.txt

Thank you and regards,
Kartik Jujare

['Maxi Miller' via deal.II User Group]

Can you try CMake-GUI? At least there you can find all occurences of openmp
and enable it.

Post by Kartik Jujare
Hello,
Would be grateful if anyone could correct or direct me to the right
solution.
As a test I have a following for loop is a step file
#pragma omp parallel
{
#pragma omp for //private(k) reduction(+:integral)
for (k = 0; k < 4; k++)
{
sleep(1);
}
}
Now the time outputs of the this for loop and another normal one (without
openmp) are the same. I think the problem lies in the flag that I am
passing in the Cmakefile but cant figure out what?
SET (MPI_CXX_COMPILE_FLAGS "-fopenmp")
//OR
SET (DEAL_II_CXX_FLAGS "-fopenmp")
I suppose I dont understand cmake very well. What would be an appropriate
place to place the above line in the CMakeLists.txt
Thank you and regards,
Kartik Jujare

[Kartik Jujare]

Dear Maxi,

Thank you so much for reminding me of that !! Works fantastic!

Regards,
Kartik Jujare

Post by 'Maxi Miller' via deal.II User Group
Can you try CMake-GUI? At least there you can find all occurences of
openmp and enable it.

Post by Kartik Jujare
Hello,
Would be grateful if anyone could correct or direct me to the right
solution.
As a test I have a following for loop is a step file
#pragma omp parallel
{
#pragma omp for //private(k) reduction(+:integral)
for (k = 0; k < 4; k++)
{
sleep(1);
}
}
Now the time outputs of the this for loop and another normal one (without
openmp) are the same. I think the problem lies in the flag that I am
passing in the Cmakefile but cant figure out what?
SET (MPI_CXX_COMPILE_FLAGS "-fopenmp")
//OR
SET (DEAL_II_CXX_FLAGS "-fopenmp")
I suppose I dont understand cmake very well. What would be an appropriate
place to place the above line in the CMakeLists.txt
Thank you and regards,
Kartik Jujare

[Jean-Paul Pelteret]

Dear Kartik,

There's both a section in the main
<https://www.dealii.org/developer/users/cmake.html#compiler> and
user-project
<https://www.dealii.org/developer/users/cmakelists.html#cmakeadvanced.setup_target>
documentation on CMake about how to configure CMake with extra compile and
linker flags. Take a look there, and perhaps the information contained
therein will help clear things up. I think that you need to extend `
DEAL_II_CXX_FLAGS` or `DEAL_II_LINKER_FLAGS` with this extra flag after
DEAL_II_INITIALIZE_CACHED_VARIABLES but before calling DEAL_II_INVOKE_AUTOPILOT
or DEAL_II_SETUP_TARGET.

I hope that this helps.
Regards,
Jean-Paul

Post by Kartik Jujare
Hello,
Would be grateful if anyone could correct or direct me to the right
solution.
As a test I have a following for loop is a step file
#pragma omp parallel
{
#pragma omp for //private(k) reduction(+:integral)
for (k = 0; k < 4; k++)
{
sleep(1);
}
}
Now the time outputs of the this for loop and another normal one (without
openmp) are the same. I think the problem lies in the flag that I am
passing in the Cmakefile but cant figure out what?
SET (MPI_CXX_COMPILE_FLAGS "-fopenmp")
//OR
SET (DEAL_II_CXX_FLAGS "-fopenmp")
I suppose I dont understand cmake very well. What would be an appropriate
place to place the above line in the CMakeLists.txt
Thank you and regards,
Kartik Jujare

[Kartik Jujare]

Dear Jean,

Thank you for pointing that out. I somehow missed the the 3.7 section while
browsing through it.

Regards,
Kartik Jujare

Post by Jean-Paul Pelteret
Dear Kartik,
There's both a section in the main
<https://www.dealii.org/developer/users/cmake.html#compiler> and
user-project
<https://www.dealii.org/developer/users/cmakelists.html#cmakeadvanced.setup_target>
documentation on CMake about how to configure CMake with extra compile and
linker flags. Take a look there, and perhaps the information contained
therein will help clear things up. I think that you need to extend `
DEAL_II_CXX_FLAGS` or `DEAL_II_LINKER_FLAGS` with this extra flag after
DEAL_II_INITIALIZE_CACHED_VARIABLES but before calling DEAL_II_INVOKE_AUTOPILOT
or DEAL_II_SETUP_TARGET.
I hope that this helps.
Regards,
Jean-Paul

Post by Kartik Jujare
Hello,
Would be grateful if anyone could correct or direct me to the right
solution.
As a test I have a following for loop is a step file
#pragma omp parallel
{
#pragma omp for //private(k) reduction(+:integral)
for (k = 0; k < 4; k++)
{
sleep(1);
}
}
Now the time outputs of the this for loop and another normal one (without
openmp) are the same. I think the problem lies in the flag that I am
passing in the Cmakefile but cant figure out what?
SET (MPI_CXX_COMPILE_FLAGS "-fopenmp")
//OR
SET (DEAL_II_CXX_FLAGS "-fopenmp")
I suppose I dont understand cmake very well. What would be an appropriate
place to place the above line in the CMakeLists.txt
Thank you and regards,
Kartik Jujare