Hi, I was looking through the code and I realized that a clear method is called 
for the nonlinear_solver irrespective of whether it is called through the a 
NonlinearImplicitSystem or a TransientNonlinearImplicitSystem. This strikes me 
as a bit wasteful. Is there are a reason for releasing all the memory allocated 
to the solver, and reconstructing it? I can override it but it seems to be a 
quite a tedious way to go about it. Is there an easy workaround for this? I am 
quite new to c++ so it doesn't strike me as a very easy thing to do. 
Thanks, 
Subramanya Sadasiva 

"But memory eventually fades. Turbulences damp out, internal strains yield to 
plastic flow, concentration inhomogeneities diffuse to uniformity. Systems tend 
to subside to very simple states,independent of their specific history."
Herbert Callen . Thermodynamics and an Introduction to Thermostatics.

----- Original Message -----
From: "Subramanya Gautam Sadasiva" <[email protected]>
To: "libmesh-users" <[email protected]>
Sent: Monday, February 25, 2013 3:39:27 PM
Subject: [Libmesh-users] transient nonlinear implicit system

Hi, 
I am trying to use SNESSetPrefix to set a name to the solver to set options for 
the solver. I do this by deriving from TransientNonlinearImplicitSystem and I 
do 
 
    PetscDMNonlinearSolver<Number>*  petsc_solver = 
    new PetscDMNonlinearSolver<Number> (*this); 
  
  // Attach the R & J calculation object
  petsc_solver->residual_object = this;
  petsc_solver->jacobian_object = this;
  // Attach the bounds calculation object 
  petsc_solver->bounds_object = this;
  
  // Get a petsc error . this is an alias for a integer 
  PetscErrorCode ierr; 
  
  petsc_solver->PetscNonlinearSolver<Number>::init(); 
 
  // The prefix is ch_solve_. I need to figure out how to 
  // put it into the documentation 
  ierr = SNESSetOptionsPrefix(petsc_solver->_snes,"ch_solve_");
 

in the constructor. This setting lasts for the first call to solve(). However - 
when I call the solver the second time, all the options are lost. Am I doing 
something wrong? Do I need to do something else to prevent the solver from 
being completely re-initialized. 
Thanks, 

Subramanya Sadasiva 

"But memory eventually fades. Turbulences damp out, internal strains yield to 
plastic flow, concentration inhomogeneities diffuse to uniformity. Systems tend 
to subside to very simple states,independent of their specific history."
Herbert Callen . Thermodynamics and an Introduction to Thermostatics.

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