Hello all!
Now I am faced with a problem associated with the memory allocation when calling of KSPSolve .
GMRES preconditioned by ASM for solving linear algebra system (obtained by the finite element spatial discretisation of Biot poroelasticity model) was chosen.
According to the output value of PetscMallocGetCurrentUsage subroutine 176 MB for matrix and RHS vector storage is required (before KSPSolve calling).
Now I am faced with a problem associated with the memory allocation when calling of KSPSolve .
GMRES preconditioned by ASM for solving linear algebra system (obtained by the finite element spatial discretisation of Biot poroelasticity model) was chosen.
According to the output value of PetscMallocGetCurrentUsage subroutine 176 MB for matrix and RHS vector storage is required (before KSPSolve calling).
But during solving linear algebra system 543 MB of RAM is required (during KSPSolve calling).
Thus, the amount of allocated memory after preconditioning stage increased three times. This kind of behaviour is critically for 3D models with several millions of cells.
Is there a way to decrease amout of allocated memory?
Is that an expected behaviour for GMRES-ASM combination?
As I remember, using previous version of PETSc didn't demonstrate so significante memory increasing.
...
Thus, the amount of allocated memory after preconditioning stage increased three times. This kind of behaviour is critically for 3D models with several millions of cells.
Is there a way to decrease amout of allocated memory?
Is that an expected behaviour for GMRES-ASM combination?
As I remember, using previous version of PETSc didn't demonstrate so significante memory increasing.
...
Vec :: Vec_F, Vec_U
Mat :: Mat_K
...
...
...
...
call MatAssemblyBegin(Mat_M,Mat_Final_Assembly,ierr)
call MatAssemblyEnd(Mat_M,Mat_Final_Assembly,ierr)
....
call VecAssemblyBegin(Vec_F_mod,ierr)
call VecAssemblyEnd(Vec_F_mod,ierr)
...
...
...
...
call PetscMallocGetCurrentUsage(mem, ierr)
print *,"Memory used: ",mem
...
...
...
call KSPSetType(Krylov,KSPGMRES,ierr)
call KSPGetPC(Krylov,PreCon,ierr)
call PCSetType(PreCon,PCASM,ierr)
call KSPSetFromOptions(Krylov,ierr)
...call KSPSolve(Krylov,Vec_F,Vec_U,ierr)
...
...
...
options = "-pc_asm_overlap 2 -pc_asm_type basic -ksp_monitor -ksp_converged_reason"
options = "-pc_asm_overlap 2 -pc_asm_type basic -ksp_monitor -ksp_converged_reason"
Kind regards,
Dmitry Melnichuk
Dmitry Melnichuk
