static char help[] = "Demonstrates VecStrideNorm().\n\n";
#include <petscvec.h>
#include "petsclog.h"
#undef __FUNCT__
#define __FUNCT__ "main"
int main(int argc,char **argv)
{
  Vec            x;               /* vectors */
  PetscReal      norm;
  PetscInt       n=10;//(argc==1)?20:((argc==2)?atoi(argv[1]):atoi(argv[2]));
  PetscErrorCode ierr;
  PetscScalar    two = 2.0;
  PetscLogStage stagenum0, stagenum1, stagenum2, stagenum3, stagenum4, stagenum5;
  //Inizializzazione di PETSC e MPI
  ierr = PetscInitialize(&argc,&argv,(char*)0,help);CHKERRQ(ierr); 
  ierr = PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);CHKERRQ(ierr);
  ierr = VecCreate(PETSC_COMM_WORLD,&x);CHKERRQ(ierr);
PetscLogStageRegister("Stage 0 of Code",&stagenum0);
  ierr = VecSetSizes(x,PETSC_DECIDE,n);CHKERRQ(ierr);
PetscLogStagePush(stagenum0);
PetscLogStagePop();
PetscLogStageRegister("Stage 1 of Code",&stagenum1);  
  ierr = VecSetBlockSize(x,2);CHKERRQ(ierr);
PetscLogStagePush(stagenum1);
PetscLogStagePop();
PetscLogStageRegister("Stage 2 of Code",&stagenum2);
  ierr = VecSetFromOptions(x);CHKERRQ(ierr);
PetscLogStagePush(stagenum2);
PetscLogStagePop();
PetscLogStageRegister("Stage 3 of Code",&stagenum3);
  ierr = VecSet(x,two);CHKERRQ(ierr);
PetscLogStagePush(stagenum3);
PetscLogStagePop();
PetscLogStageRegister("Stage 4 of Code",&stagenum4);
  ierr = VecNorm(x,NORM_1,&norm);CHKERRQ(ierr);
PetscLogStagePush(stagenum4);
PetscLogStagePop();
PetscLogStageRegister("Stage 5 of Code",&stagenum5);  
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Norm 1 of entire vector %G\n",norm);CHKERRQ(ierr);
PetscLogStagePush(stagenum5);
PetscLogStagePop();
  ierr = VecDestroy(&x);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return 0;
}