test_lin_nonlin_evol.m

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% small script performing one time step in linear and nonlinear
% mode and comparing the error. The error should ideally only be in the
% order of 10^-15

% Bernard Haasdonk 21.5.2007

% setup parameters, that switching between lin-evol and nonlin-evol 
% is possible
load demo_nonlin_evol_params
params.operators_algorithm = 'fv_operators_implicit_explicit';    
%params.T = 100*params.T/params.nt;
%params.nt = 100;
params.c_init = 1; % in case of no structure
params.k = 5e-8;

% get solution in linear case:
params.rb_problem_type = 'lin_evol';
grid = construct_grid(params);
Ulin = detailed_simulation(grid,params);      

% get solution in nonlinear-case
params.rb_problem_type = 'nonlin_evol';
Unonlin = detailed_simulation(grid,params);      

% compare
if ~isequal(Ulin(:,1),Unonlin(:,1))
  error('initial data does not correspond!!');
end; 

% visualize error
params.title = 'difference Unonlin-Ulin';
plot_element_data_sequence(grid,Unonlin-Ulin,params);

disp('detailed_simulation for lin_evol and nonlin_evol give');
if max(max(abs(Unonlin-Ulin))) > 1e-14
  disp('different results! Test failed');
else
  disp('identical result! Test OK');
end;

% TO BE ADJUSTED TO NEW SYNTAX
%| \docupdate