static char help[] = "We load a 2d mesh from msh file and create a corresponding DMPlex.\n\n\n";

#include <petscdmplex.h>
#include <petscksp.h>
#include <petscds.h>

void top_displacement(const PetscReal x[], PetscScalar *u, void *ctx)
{
  *u = x[1]==0.0? 0.0:0.2;
}

#undef __FUNCT__
#define __FUNCT__ "main"
int main(int argc, char **argv)
{
  MPI_Comm        comm;
  DM              dm;
  KSP             ksp;
  Vec             u,r;
  PetscErrorCode  ierr;

  const char *    filename = "/home/luc/research/simulations/Petsc_DMPlex/simple_test/square.msh";
  
  ierr = PetscInitialize(&argc, &argv, (char *)0, help);CHKERRQ(ierr);
  comm = PETSC_COMM_WORLD;
  
  //Create the DM using a gmsh file
  ierr = DMPlexCreateFromFile(comm, filename, PETSC_TRUE, &dm);CHKERRQ(ierr);
  ierr = DMPlexSetRefinementUniform(dm, PETSC_FALSE);CHKERRQ(ierr);
  ierr = DMPlexAddBoundary(dm, PETSC_TRUE,"wall","marker",(void (*)())top_displacement,1,&id,user)
  /* Must have boundary marker for Dirichlet conditions */
  ierr = DMViewFromOptions(dm, NULL, "-dm_view");CHKERRQ(ierr);
  
  ierr = KSPCreate(comm, &ksp);CHKERRQ(ierr);
  ierr = KSPSetDM(ksp, dm);CHKERRQ(ierr);
  
  ierr = PetscFinalize();
  return(0);
}