function completed = example_nonlinearParam_reach_01_tank()
% example_nonlinearParam_reach_01_tank - example of nonlinear reachability 
%    analysis with uncertain parameters, taken from [1], which can also be
%    found in Sec. 3.4.5 of [2].
%
% Syntax:
%    completed = example_nonlinearParam_reach_01_tank()
%
% Inputs:
%    -
%
% Outputs:
%    completed - true/false 
%
% References:
%   [1] M. Althoff et al. "Reachability analysis of nonlinear systems with 
%       uncertain parameters using conservative linearization"  
%   [2] M. Althoff “Reachability analysis and its application to the safety 
%       assessment of autonomous cars"

% Authors:       Matthias Althoff
% Written:       19-August-2016
% Last update:   23-April-2020 (restructure params/options)
% Last revision: ---

% ------------------------------ BEGIN CODE -------------------------------

% Parameters --------------------------------------------------------------

params.tFinal = 400;                                     % final time
params.R0 = zonotope([[2; 4; 4; 2; 10; 4],0.2*eye(6)]);  % initial set
params.U = zonotope([0,0.005]);                          % uncertain input

params_ = params;
params_.paramInt = interval(0.0148,0.015);          % uncertain paramters


% Reachability Settings ---------------------------------------------------

options.timeStep = 0.5;
options.taylorTerms = 4;
options.zonotopeOrder = 10;
options.tensorOrder = 2;
options.alg = 'lin';


% System Dynamics ---------------------------------------------------------

% tank system with certain pararmters
tank = nonlinearSys(@tank6Eq);

% tank system with uncertain parameters
tankParam = nonlinParamSys(@tank6paramEq);


% Reachability Analysis ---------------------------------------------------        

% compute reachable set of tank system without uncertain parameters
timerVal = tic;
RcontNoParam = reach(tank, params, options);
tComp = toc(timerVal);
disp(['computation time of reachable set without uncertain parameters: ',num2str(tComp)]);

% compute reachable set of tank system with uncertain parameters
options.intermediateTerms = 4;
timerVal = tic;
RcontParam = reach(tankParam, params_, options);
tComp = toc(timerVal);
disp(['computation time of reachable set with uncertain parameters: ',num2str(tComp)]);


% Simulation --------------------------------------------------------------

% number of initial points
simOpt.points = 10;

% random simulation
simRes = simulateRandom(tank,params,simOpt);


% Visualization -----------------------------------------------------------

dims = {[1,2],[3,4],[5,6]};

% plot different projections
for i = 1:length(dims)
    
    figure; hold on; box on;
    projDims = dims{i};
    useCORAcolors("CORA:contDynamics", 2)

    % plot reachable sets
    plot(RcontParam,projDims,'DisplayName','parametric');
    plot(RcontNoParam,projDims,'DisplayName','non-parametric');
    
    % plot initial set
    plot(RcontParam.R0,projDims,'DisplayName','Initial set');
  
    % plot simulation results
    plot(simRes,projDims,'DisplayName','Simulations');

    % label plot
    xlabel(['x_{',num2str(projDims(1)),'}']);
    ylabel(['x_{',num2str(projDims(2)),'}']);
    legend();
end

completed = true;

% ------------------------------ END OF CODE ------------------------------
