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generating/extracting a simulink restart state from system output? ?problem with 'discrete' blocks?

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jessupj
jessupj on 14 Sep 2020
Edited: jessupj on 17 Sep 2020
I need to periodically interrupt a SIMULINK model, and restart it with the the state it was in at some previous time (with some changes to model parameters using environmental variables).
The concise questions is: how do i take 'XXX = sim(gcs)' and define a restart state from a timeslice of 'XXX'?
The gist of what i'm trying to do is as follows:
%% LOAD SYSTEM
if ~isempty(gcs); close_system(gcs,0); end
SIMSYS = load_system(systemname) ;
setActiveConfigSet( SIMSYS, 'Configuration1' );
cset = getConfigSet( gcs, 'Configuration1' );
set_param(cset,'SaveFormat', 'StructureWithTime' );
set_param(cset,'StateSaveName', 'state_history');
% SIMULATE over intervals
for kk = 1:5; %length(tstarts); %1
tstart = tstarts(kk);
tend = tends(kk);
set_param(cset,'StartTime', string(tstart) );
set_param(cset,'StopTime', string(tend) );
set_param(cset,'SaveState', 'on');
if kk==1; % set initial details and paramter values
set_param(cset,'Solver','VariableStepAuto')
set_param(cset,'SolverName','VariableStepAuto')
set_param(cset, 'LoadInitialState','off');
set_param(cset, 'LoggingToFile','off');
B.R = 3;
B.C = 0.12;
B.P = 17.0;
end
try
simOUT = sim( gcs, cset );
catch ME
rethrow(ME)
end
% modify things for next iteration
set_param(cset, 'LoadInitialState','on');
% MAKE a variable 'rststate' from the
rststate = simOUT.state_history;
% get record time closest to next
[~,rst_kt] = min( abs(rststate.time - tstart) );
%***
for rstkk = 1:length(rststate.signals);
rststate.signals(rstkk).values = rststate.signals(rstkk).values( rst_kt );
end
rststate.time = rststate.time(rst_kt);
% SET intial state as restart state
set_param(cset, 'InitialState', 'rststate' );
%[B.R, B.C, B.P] = parameter_update(some system monitors)
end
system_close(gcs,0)
Unfortunately, this fails at the SECOND call to 'sim' with the error
Size mismatch in the initial state for model 'your_model'. The signals(136).values field in the initial state structure has
1 element(s), where as the corresponding state 'Discrete' in block 'your_model/Solver Configuration' has 2 element(s)
What I've done before is manually remove these blocks from the restart state at line *** a la:
rststate.signals(136)=[] % or similar
but this works inconsistently and is model specific. Namely, when i do remove entry 136, which corresponds to the Solver Configuration, I get the following error which is absolutely perplexing:
Unable to load the specified initial state for model 'your_model'. Cannot find a matching block state
corresponding to element 135 of signals structure array
To me , it seems like the indexing ouf the output state and the initial state are different. THat's not a typo; removing element 136 from the initial signal gives a model that element 135 is not provided. The following don't work either, in the sense that they remove the 136th signal element, and produces and undefined element 135.
%rmblk = find( ismember( {rststate.signals(1:end).label}, 'Discrete') )
rmblk = find( contains( {rststate.signals(1:end).blockName },'Solver'));
rststate.signals(rmblk) = [];

Accepted Answer

Fangjun Jiang
Fangjun Jiang on 15 Sep 2020
Just got this:
https://www.mathworks.com/help/simulink/slref/saving-and-restoring-simulation-operating-point.html
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