Off-diagonal Jacobian support for Nodal BCs

Peterson, John W.¹  Andrs, David¹  Gaston, Derek R.¹  Permann, Cody J.¹  Slaughter, Andrew E.¹ 

[1] Idaho National Lab. (INL), Idaho Falls, ID (United States)

关键词: jacobian;    MOOSE;   

DOI  :  10.2172/1178371
RP-ID  :  INL/EXT--15-34246
PID  :  OSTI ID: 1178371

学科分类：社会科学、人文和艺术（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

In this brief note, we describe the implementation of o-diagonal Jacobian computations for nodal boundary conditions in the Multiphysics Object Oriented Simulation Environment (MOOSE) [1] framework. There are presently a number of applications [2{5] based on the MOOSE framework that solve complicated physical systems of partial dierential equations whose boundary conditions are often highly nonlinear. Accurately computing the on- and o-diagonal Jacobian and preconditioner entries associated to these constraints is crucial for enabling ecient numerical solvers in these applications. Two key ingredients are required for properly specifying the Jacobian contributions of nonlinear nodal boundary conditions in MOOSE and nite element codes in general: 1. The ability to zero out entire Jacobian matrix rows after \normal" assembly has taken place, and eciently replace the contents of those rows with the contributions associ- ated to the nodal boundary conditions. 2. An interface for allowing users to specify both the residual and Jacobian contributions associated to their nonlinear boundary condition.