It's 3d incompressible RT simulation. My pressure between serial and parallel calculation is off by 10^(-14) in relative error. it eventually build up at later time. I want to rule out the possibilities that PETSc give me bad solution. pressure scale is 10^(-2).
I use PetscScalar. thanks @Jed Brown for confirming that but I have Segmentation Violation when retrieving x. I allocated memory for the array x (PetscScalar type). if not for quadruple precision, there is no error. thanks @Satish Balay. I will update code petsc-3.7 later.
