[Trilinos-Users] NOx-LOCA issue with convergence - Arc length continuation

[Nico Schlömer]

Hi Kumar,

it'd be useful to know the parameters you use to drive the computations.
Also, the tail'ed output you attached suggests that a number of 
continuation steps have been completed successfully; is that correct? 
The output there would also help debugging.

Cheers,
Nico



On 06/21/2011 03:14 PM, narendiran kumar wrote:
> hi,
>
> I am using nox package for solving vector problem (nof. eqn 200) using
> arc-length continuation. I have modified chancontinuation example
> program and i gave initial guess in vector form (for n = 200 eqn). When
> i was compile, i am getting warring. I guess it's because of initial
> guess. Can anyone please help me.
>
> thanks in advance,
>
> Regards,
> K. Narendiran
>
>
> Example warring o/p:
>
> ************************************************
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Start of Continuation Step 11 : Parameter: Da = 8.747e-01 from 9.511e-01
> Continuation Method: Arc Length
> Current step size = 8.434e-05 Previous step size = 5.812e-05
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Warning: NOX::Solver::LineSearchBased::init() - The solution passed into
> the solver (either through constructor or reset method) is already
> converged! The solver wil not attempt to solve this system since status
> is flagged as converged.
>
> ************************************************************************
> -- Nonlinear Solver Step 0 --
> ||F|| = 8.598e+00 step = 0.000e+00 dx = 0.000e+00 (Converged!)
> ************************************************************************
>
> ************************************************************************
> -- Final Status Test Results --
> Converged....OR Combination ->
> Converged....F-Norm = 6.065e-01 < 1.000e+00
> (Length-Scaled Two-Norm, Absolute Tolerance)
> ??...........Number of Iterations = -1 < 20
> ************************************************************************
>
> ************************************************************************
> -- Nonlinear Solver Step 0 --
> ||F|| = 8.598e+00 step = 0.000e+00 dx = 0.000e+00 (Converged!)
> ************************************************************************
>
> ************************************************************************
> -- Final Status Test Results --
> Converged....OR Combination ->
> Converged....F-Norm = 6.065e-01 < 1.000e+00
> (Length-Scaled Two-Norm, Absolute Tolerance)
> ??...........Number of Iterations = -1 < 20
> ************************************************************************
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> End of Continuation Step 11 : Parameter: Da = 8.747e-01 from 9.511e-01
> --> Step Converged in 0 Nonlinear Solver Iterations!
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
> Calling Predictor with method: Secant
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> Arc-length scaling calculation for parameter Da:
> Parameter component of predictor before rescaling = 9.058e+02
> Scale factor from previous step 1.000e-03
> Parameter contribution to arc-length equation = 9.058e-01
>
> Parameter component of predictor after rescaling = 9.058e+02
> New scale factor (theta) = 1.000e-03
> Parameter contribution to arc-length equation = 9.058e-01
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> At parameter value: 0.87472249 the solution vector (norm=0.0096190908) is
> 0.00045035754 0.0011253381 0.00036360756 0.00090869718 0.000277962
> 0.00069468095 ... 0.0053114264 0.00023180336
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
> ******************************************
>
>
>
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