Hi everybody!
I continue to learn Gmsh API functions.
This is a simple example of how I use these funtions:
// --- main.cpp ---
//#include suitable files
class Elem // abstract geometrical element
{
public:
char geoFileName[256];
char mshFileName[256];
void Init(int Number)
{
// initialization of the names
// of .geo file (geoFileName) and .msh file
(mshFileName)
}
void CreateGeo()
{
// write .geo file
}
// create 2D mesh using Gmsh API functions
void CreateMsh()
{
GmshInitialize();
GModel *m = new GModel();
m->readGEO(geoFileName);
m->mesh(2);
m->writeMSH(mshFileName, 2.1, true);
delete m;
GmshFinalize();
}
};
int main(int argc, char **argv)
{
int i, N = 3;
Elem *elem = new Elem[N];
for (i = 0; i < N; i++) {
elem[i].Init(i);
elem[i].CreateGeo();
elem[i].CreateMsh();
}
delete[] elem;
}
// --- end of main.cpp ---
The full text of main.cpp is attached.
Now I encountered such trouble: if I use Gmsh API in
parallel version of my code, my program crushes under
execution.
For parallelization I use OpenMP pragmas:
// --- main_omp.cpp ---
// the part of main.cpp without changes
int main(int argc, char **argv)
{
int i, N = 3;
Elem *elem = new Elem[N];
// parallelization with OpenMP
omp_set_num_threads(N);
#pragma omp parallel for private(i)
for (i = 0; i < N; i++) {
elem[i].Init(i);
elem[i].CreateGeo();
elem[i].CreateMsh();
}
delete[] elem;
}
// --- end of main_omp.cpp ---
The full text of main_omp.cpp is attached too.
I tried to use funtions GmshInitialize() and
GmshFinalize() in main funtion to avoid these global
instructions in parallel part of code, but it didn't work.
How can I use Gmsh API in my parallel code?
Thanks
Mikhail Artemiev, PhD student, NSTU
#include <iostream>
#include <fstream>
#include <gmsh/Gmsh.h>
#include <gmsh/GModel.h>
class Elem
{
public:
char geoFileName[256];
char mshFileName[256];
void Init(int Number)
{
char ch[8];
itoa(Number, ch, 10);
strcpy(geoFileName, ch);
strcat(geoFileName, ".geo");
strcpy(mshFileName, ch);
strcat(mshFileName, ".msh");
}
void CreateGeo()
{
std::ofstream out(geoFileName);
out << "Point(1) = {0, 0, 0, 0.1};\n";
out << "Point(2) = {1, 0, 0, 0.1};\n";
out << "Point(3) = {0, 1, 0, 0.1};\n";
out << "Line(1) = {1, 2};\n";
out << "Line(2) = {2, 3};\n";
out << "Line(3) = {3, 1};\n";
out << "Line Loop(4) = {1, 2, 3};\n";
out << "Plane Surface(1) = {4};\n";
out.close();
}
void CreateMsh()
{
GmshInitialize();
GModel *m = new GModel();
m->readGEO(geoFileName);
m->mesh(2);
m->writeMSH(mshFileName, 2.1, true);
delete m;
GmshFinalize();
}
};
int main(int argc, char **argv)
{
int i, N = 3;
Elem *elem = new Elem[N];
for (i = 0; i < N; i++) {
elem[i].Init(i);
elem[i].CreateGeo();
elem[i].CreateMsh();
}
delete[] elem;
}
#include <iostream>
#include <fstream>
#include <gmsh/Gmsh.h>
#include <gmsh/GModel.h>
#include <omp.h>
class Elem
{
public:
char geoFileName[256];
char mshFileName[256];
void Init(int Number)
{
char ch[8];
itoa(Number, ch, 10);
strcpy(geoFileName, ch);
strcat(geoFileName, ".geo");
strcpy(mshFileName, ch);
strcat(mshFileName, ".msh");
}
void CreateGeo()
{
std::ofstream out(geoFileName);
out << "Point(1) = {0, 0, 0, 0.1};\n";
out << "Point(2) = {1, 0, 0, 0.1};\n";
out << "Point(3) = {0, 1, 0, 0.1};\n";
out << "Line(1) = {1, 2};\n";
out << "Line(2) = {2, 3};\n";
out << "Line(3) = {3, 1};\n";
out << "Line Loop(4) = {1, 2, 3};\n";
out << "Plane Surface(1) = {4};\n";
out.close();
}
void CreateMsh()
{
GmshInitialize();
GModel *m = new GModel();
m->readGEO(geoFileName);
m->mesh(2);
m->writeMSH(mshFileName, 2.1, true);
delete m;
GmshFinalize();
}
};
int main(int argc, char **argv)
{
int i, N = 3;
Elem *elem = new Elem[N];
omp_set_num_threads(N);
#pragma omp parallel for private(i)
for (i = 0; i < N; i++) {
elem[i].Init(i);
elem[i].CreateGeo();
elem[i].CreateMsh();
}
delete[] elem;
}
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