misc.ss.combineInputSignals: new function to automatically combine input...

misc.ss.combineInputSignals: new function to automatically combine input signals that suite to the input names of a state space.

+misc/+ss/combineInputSignals.m

+function u = combineInputSignals(myStateSpace, t, varargin)
+%MISC.SS.COMBINEINPUTSIGNALS reads the input varargin and searches for name-value-pairs that
+%coincide with one of myStateSpace.InputName. If a pair is found, that signal is used
+%as elements of u. For inputs that are not found, u-elements are set to zero.
+%
+% Inputs:
+%	myStateSpace	state space for which an input signal is designed
+%	t				time for which u shall be defined
+%	varargin		name-value-pairs containing input signals with names coinciding
+%					with myStateSpace.InputName
+% Outputs:
+%	u				quantity vector of input signals suiting to myStateSpace for the
+%					time t.
+%
+% Example:
+% -------------------------------------------------------------------------
+% 	myStateSpace = ss(-1, [1, 2], 1, [], 'InputName', {'control', 'disturbance'});
+%	t = linspace(0, 4, 201);
+%	disturbanceSignal = quantity.Symbolic(sin(sym('t')), 'grid', t, ...
+%		'variable', sym('t'), 'name', 'disturbance');
+%	u = misc.ss.combineInputSignals(myStateSpace, t, 'disturbance', disturbanceSignal);
+%	y = quantity.Discrete(lsim(myStateSpace, u.on(), t), 'grid', t, ...
+%		'gridName', 't', 'name', 'y');
+%	plot([y; u]);
+% -------------------------------------------------------------------------
+
+% read name of input names from myStateSpace and calculate input lengths
+myInputName = misc.ss.removeEnumeration(myStateSpace.InputName);
+myInputNameUnique = unique(myInputName, 'stable');
+myInputLength = zeros(size(myInputNameUnique));
+for it = 1 : numel(myInputLength)
+	myInputLength(it) = sum(strcmp(myInputNameUnique{it}, myInputName));
+end
+
+% search for input signals in varargin or use default value = 0 instead
+myParser = misc.Parser();
+for it = 1 : numel(myInputNameUnique)
+	myParser.addParameter(myInputNameUnique{it}, ...
+		quantity.Discrete(zeros(numel(t), myInputLength(it)), ...
+		'grid', t, 'gridName', 't', 'name', myInputNameUnique{it}), ...
+		@(v) isa(v, 'quantity.Discrete') & isvector(v) & (numel(v)==myInputLength(it)));
+end
+myParser.parse(varargin{:});
+
+% finally, create resulting input vector
+u = myParser.Results.(myInputNameUnique{1});
+for it = 2 : numel(myInputNameUnique)
+	u = [u; myParser.Results.(myInputNameUnique{it})];
+end % for
+
+end % combineInputSignals()
\ No newline at end of file

+unittests/+misc/testSs.m

@@ -4,6 +4,19 @@ function [tests] = testSs()
 tests = functiontests(localfunctions());
 end
 
+function testCombineInputSignals(tc)
+myStateSpace = ss(-1, [1, 2], 1, [], 'InputName', {'control', 'disturbance'});
+t = linspace(0, 4, 201);
+disturbanceSignal = quantity.Symbolic(sin(sym('t')), 'grid', t, ...
+	'variable', sym('t'), 'name', 'disturbance');
+u = misc.ss.combineInputSignals(myStateSpace, t, 'disturbance', disturbanceSignal);
+y = quantity.Discrete(lsim(myStateSpace, u.on(), t), 'grid', t, ...
+	'gridName', 't', 'name', 'y');
+
+odeResiduum = - y.diff(1, 't') - y + 2*disturbanceSignal;
+tc.verifyEqual(odeResiduum.abs.median(), 0, 'AbsTol', 5e-4);
+end
+
 function testRemoveEnumeration(tc)
 tc.verifyEqual(misc.ss.removeEnumeration({'a(1)', 'a(2)', 'b'}), {'a', 'a', 'b'});
 tc.verifyEqual(misc.ss.removeEnumeration({'a(1)', 'a(2)', 'b'}, false), {'a', 'a', 'b'});