Unable to perform assignment because brace indexing is not supporte... (2025)

clear all

close all

clc

syms x(t) y(t) z(t) A B C D E FF G H I J K LL MM N O P Q R S

eqn1 = diff(x(t),t) == 1/ A * ((B * C - B * x(t))) - (x(t) * D * E - FF*((y(t) * z(t)^2)/(z(t)^2 + G * z(t) + G * H))) / ((1/I) + 1/(J * (((K*(FF* x(t) * D * E - ((y(t) * z(t)^2)/(z(t)^2 + G * z(t) + G*H))))) + LL * (((G * FF * x(t) * D * E/z(t)) - ((y(t) * G * z(t))/(z(t)^2 + G * z(t) + G*H)))) + MM * ((((G * H *FF* x(t) * D * E/z(t)^2) - ((y(t) * G * H)/(z(t)^2 + G * z(t) + G*H))))))) / (K * (FF * x(t) * D * E - ((y(t) * z(t)^2)/(z(t)^2 + G * z(t) + G*H)))));

eqn2 = diff(y(t),t) == (x(t) * D * E - FF*((y(t) * z(t)^2)/(z(t)^2 + G * z(t) + G*H))) / ((1/I) + 1/(J * (((K*(FF* x(t) * D * E - ((y(t) * z(t)^2)/(z(t)^2 + G * z(t) + G * H)) ) + LL * (((G * FF * x(t) * D * E/z(t)) - (( y(t) * G * z(t))/(z(t)^2 + G * z(t) + G*H)))) + MM * ((((G * H * FF * x(t) * D * E / z(t)^2) - ((y(t) * G * H)/(z(t)^2 + G * z(t) + G * H))))))/ (K * (FF * x(t) * D * E - (( y(t) * z(t)^2)/(z(t)^2 + G * z(t) + G * H))))))) - 0.162 * exp(-5153/E) * (((N * (( y(t) * G * H)/(z(t)^2 + G * z(t) + G*H)))/O) - 1)^2 * (P / ((N * (((y(t) * G * H)/(z(t)^2 + G * z(t) + G * H))))) / O));

eqn3 = z(t) + 2 * N - ((y(t) * G * z(t))/(z(t)^2 + G * z(t) + G*H)) - 2 * (( y(t) * G * H)/(z(t)^2 + G * z(t) + G*H)) - ((N * Q * z(t))/(z(t)^2 + Q * z(t) + Q*R)) - 2 * ((N * Q * R)/(z(t)^2 + Q * z(t) + Q*R)) - S/z(t) == 0;

eqns = [eqn1 eqn2 eqn3];

vars = [x(t); y(t); z(t)];

origVars = length(vars);

M = incidenceMatrix(eqns, vars);

[eqns, vars] = reduceDifferentialOrder(eqns, vars);

isLowIndexDAE(eqns,vars);

f = daeFunction(eqns,vars, A, B, C, D, E, FF, G, H, I, J, K, LL, MM, N, O, P, Q, R, S);

A = 1.5e-6;

B = 1.66667e-5;

C = 6.51332e-2;

D = 8.314;

E = 323.15;

FF = 149;

G = 6.24;

H = 5.68e-5;

I = 4.14e-6;

J = 7.25E-2;

K = 2.98e-9;

LL = 2.35e-9;

MM = 1.69e-9;

N = 8;

O = 1.07e-7;

P = 10;

Q = 1.7e-3 ;

R = 6.55e-8;

S = 5.3e-8 ;

F = @(t, Y, YP) f(t, Y, YP, A, B, C, D, E, FF, G, H, I, J, K, LL, MM, N,O, P, Q, R, S);

vars;

y0est = [4.58E-02; 1.58; 1];

yp0est = zeros(3,1);

opt = odeset('RelTol', 10.0^(-7), 'AbsTol' , 10.0^(-7));

[y0, yp0] = decic(F, 0, y0est, [], yp0est, [], opt);

[tSol,ySol] = ode15i(F, [6720, 27840], y0, yp0, opt);

for k = 1:origVars

S{k} = char(vars(k));

end

Unable to perform assignment because brace indexing is not supported for variables of this type.

Error in Example01Sept2018 (line 57)

S{k} = char(vars(k));

for k = 1:origVars

S{k} = char(vars(k));

end

for k = 1:origVars

S(k) = char(vars(k));

end

Unable to perform assignment because the left and right sides have a different number of elements.

Error in Example01Sept2018 (line 57)

S(k) = char(vars(k));