Difference between revisions of "Programming/C"
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== Programming Details == | == Programming Details == | ||
| − | C is a general-purpose, imperative computer programming language. There are some derivations of the language due to the | + | C is a general-purpose, imperative computer programming language. There are some derivations of the language due to the modernization of the original specification in the form of C++ and C#. |
| + | {| | ||
| + | |style="width:5%; border-width: 0;cellpadding=0" | [[File:icon_tick.png]] | ||
| + | |style="width:95%; border-width: 0;cellpadding=0" | There is direct support for [[programming/OpenMP|openMP]] and [[programming/OpenMPI|openMPI]]. | ||
| + | |- | ||
| + | |} | ||
| + | === Programming example === | ||
| − | |||
| − | + | <pre style="background-color: #f5f5dc; color: black; font-family: monospace, sans-serif;"> | |
| − | |||
| − | |||
| − | |||
| − | <pre style="background-color: # | ||
#include <omp.h> | #include <omp.h> | ||
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<pre style="background-color: black; color: white; border: 2px solid black; font-family: monospace, sans-serif;"> | <pre style="background-color: black; color: white; border: 2px solid black; font-family: monospace, sans-serif;"> | ||
| − | + | [username@login01 ~]$ module add gcc/8.2.0 | |
| − | [username@login01 ~]$ module add gcc/ | ||
[username@login01 ~]$ gcc -o test2 -fopenmp test2.c (openMP support) | [username@login01 ~]$ gcc -o test2 -fopenmp test2.c (openMP support) | ||
[username@login01 ~]$ ./test2 | [username@login01 ~]$ ./test2 | ||
| Line 52: | Line 52: | ||
Hello World from thread = 0 | Hello World from thread = 0 | ||
Number of threads = 1 | Number of threads = 1 | ||
| − | |||
</pre> | </pre> | ||
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The following modules are available for C | The following modules are available for C | ||
| − | * module | + | * module add gcc/8.2.0 (GNU compiler) |
| − | * module | + | * module add intel/compiler/64/2016.2.181 (Intel compiler) |
| − | + | {| | |
| − | + | |style="width:5%; border-width: 0;cellpadding=0" | [[File:icon_exclam3.png]] | |
| − | + | |style="width:95%; border-width: 0;cellpadding=0" | OpenMP is a library directive within the compiler and does not require any additional module to be loaded. | |
| − | + | |- | |
| + | |} | ||
== Usage Examples == | == Usage Examples == | ||
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== Batch example == | == Batch example == | ||
| − | <pre style="background-color: # | + | |
| + | <pre style="background-color: #C8C8C8; color: black; border: 2px solid #C8C8C8; font-family: monospace, sans-serif;"> | ||
#!/bin/bash | #!/bin/bash | ||
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#SBATCH -p compute | #SBATCH -p compute | ||
#SBATCH --exclusive | #SBATCH --exclusive | ||
| + | #SBATCH --mail-user= your email address here | ||
echo $SLURM_JOB_NODELIST | echo $SLURM_JOB_NODELIST | ||
module purge | module purge | ||
| − | module add gcc/ | + | module add gcc/8.2.0 |
export I_MPI_DEBUG=5 | export I_MPI_DEBUG=5 | ||
| Line 92: | Line 94: | ||
/home/user/CODE_SAMPLES/OPENMP/demo | /home/user/CODE_SAMPLES/OPENMP/demo | ||
| − | |||
</pre> | </pre> | ||
| Line 101: | Line 102: | ||
</pre> | </pre> | ||
| − | == | + | == Next Steps == |
* [https://en.wikipedia.org/wiki/C_(programming_language) https://en.wikipedia.org/wiki/C_(programming_language)] | * [https://en.wikipedia.org/wiki/C_(programming_language) https://en.wikipedia.org/wiki/C_(programming_language)] | ||
| Line 108: | Line 109: | ||
* [https://computing.llnl.gov/tutorials/openMP/ https://computing.llnl.gov/tutorials/openMP/] | * [https://computing.llnl.gov/tutorials/openMP/ https://computing.llnl.gov/tutorials/openMP/] | ||
| − | + | {{Languagespagenav}} | |
Latest revision as of 11:25, 16 November 2022
Contents
Programming Details
C is a general-purpose, imperative computer programming language. There are some derivations of the language due to the modernization of the original specification in the form of C++ and C#.
|
There is direct support for openMP and openMPI. |
Programming example
#include <omp.h>
#include <stdio.h>
int main (int argc, char *argv[]){
int nthreads, tid;
/* Fork a team of threads giving them their own copies of variables*/
#pragma omp parallel
{
/* Obtain thread number */
tid = omp_get_thread_num();
printf("Hello World from thread = %d\n", tid);
/* Only Master thread does this */
if(tid == 0)
{
nthreads = omp_get_num_threads();
printf("Number of threads = %d\n", nthreads);
}
} /* All threads join together and disband */
return (0);
}
Compilation
The program would be compiled in the following way, optional Intel compiler available too:
[username@login01 ~]$ module add gcc/8.2.0 [username@login01 ~]$ gcc -o test2 -fopenmp test2.c (openMP support) [username@login01 ~]$ ./test2 Hello World from thread = 0 Number of threads = 1
Modules Available
The following modules are available for C
- module add gcc/8.2.0 (GNU compiler)
- module add intel/compiler/64/2016.2.181 (Intel compiler)
|
OpenMP is a library directive within the compiler and does not require any additional module to be loaded. |
Usage Examples
Batch example
#!/bin/bash #SBATCH -J openmpi-single-node #SBATCH -N 1 #SBATCH --ntasks-per-node 28 #SBATCH -o %N.%j.%a.out #SBATCH -e %N.%j.%a.err #SBATCH -p compute #SBATCH --exclusive #SBATCH --mail-user= your email address here echo $SLURM_JOB_NODELIST module purge module add gcc/8.2.0 export I_MPI_DEBUG=5 export I_MPI_FABRICS=shm:tmi export I_MPI_FALLBACK=no /home/user/CODE_SAMPLES/OPENMP/demo
[username@login01 ~]$ sbatch demo.job Submitted batch job 289552