Does NonlinearVariationalSolver perform line search under the hood ?

Question

I am using it as below:

U = Function(W)     # the most recently computed solution
R  = action(F, U)     # residual at  U
DR  = derivative(R,  U)   # Gateaux derivative in dir. of  U at U
problem = NonlinearVariationalProblem(R, U, bcs, DR)
solver  = NonlinearVariationalSolver(problem)

I understand NonlinearVariationalSolver does a Newton-Raphson under the hood. Does it also do a line search to calculate the next iterate for the solution ?

Answer 1

Nope. If you want that, switch to the PETSc snes solver by adding the following:

solver.parameters['nonlinear_solver']='snes' 
solver.parameters['snes_solver']['line_search'] = 'bt' 
info(solver.parameters, True)

The last line will output the other options you can choose from.