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POHow to estimate coefficient of system of ODE with Matlab
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copied!<p>would like to find coefficient of system below which has variable x</p> <pre><code>dS/dt = a1*S+a2*D+a3*F+a10*x dD/dt = a4*S+a5*D+a6*F+a11*x dF/dt = a7*S+a8*D+a9*F+a12*x </code></pre> <p>then i try without variable x, got error</p> <pre><code>dS/dt = a1*S+a2*D+a3*F dD/dt = a4*S+a5*D+a6*F dF/dt = a7*S+a8*D+a9*F function getDE % find [A, fval] = fminsearch(@objFcn, 10*randn(3)); end function objVal = objFcn(A) % time span to be integrated over tspan = [1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27]; % your desired data x11 = [0.208408965651696e-3 -0.157194487523421e-2 -0.294739401402979e-2 0.788206708183853e-2 0.499394753201753e-2 0.191468321959759e-3 0.504980449104750e-2 0.222150494088535e-2 0.132091821964287e-2 0.161118434883258e-2 -0.281236534046873e-2 -0.398055875132037e-2 -0.111753680372819e-1 0.588868146012489e-2 -0.354191562612469e-2 0.984082837373291e-3 -0.116041186868374e-1 0.603027845850267e-3 -0.448778128168742e-2 -0.127561485214862e-1 -0.412027655195339e-2 0.379387381798949e-2 -0.602550446997765e-2 -0.605986284736216e-2 -0.751396992404410e-2 0.633613424008655e-2 -0.677581832613623e-2]; y11 = [ -21321.9719565717 231.709204951251 1527.92905167191 -32.8508507060675 54.9408176234139 -99.4222178124229 -675.771433486265 42.0838668074923 -12559.3183308951 5.21412214166344*10^5 1110.50031772203 3.67149699000155 -108.543878970269 -8.48861069398811 -521.810552387313 26.4792411876883 -8.32240296737599 -1085.40982521906 -44.1390030597906 -203.891397612798 -56.3746416571417 -218.205643256096 -178.991498697065 -42.2468018350386 .328546922634921 -1883.18308996621 111.747881085748]; z11 = [ 1549.88755331800 -329.861725802688 8.54200301129155 -283.381775745327 -54.5469129127573 1875.94875597129 -16.2230517860850 6084.82381954832 1146.15489803104 -456.460512914647 104.533252701641 16.3998365630734 11.5710907832054 -175.370276462696 33.8045539958636 2029.50029336951 1387.92643570857 9.54717543291120 -1999.09590358328 29.7628085078953 2.58210333216737*10^6 57.7969622731082 -6.42551196941394 -8549.23677077892 -49.0081775323244 -72.5156360537114 183.539911458475]; y_desired = [x11; y11; z11].'; % solve the ODE y0 = y_desired(1,:); [~,y_real] = ode45(@(~,y) A*y, tspan, y0); % objective function value: sum of squared quotients objVal = sum((1 - y_real(:)./y_desired(:)).^2); end </code></pre> <p>error</p> <pre><code>>> getDE ??? Error: File: objFcn.m Line: 15 Column: 7 Expression or statement is incorrect--possibly unbalanced (, {, or [. Error in ==> fminsearch at 205 fv(:,1) = funfcn(x,varargin{:}); Error in ==> getDE at 3 [A, fval] = fminsearch(@objFcn, 10*randn(3)); </code></pre>

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