Don't understand the reason this code is giving me errors.

The code that is producing the error is below. It says:

>> test

Error: File: test.m Line: 32 Column: 58

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

>> test

Error: File: test.m Line: 30 Column: 60

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

Code that produces errors is below.

clc;
mass = 13.5;
Jx = 0.8244;
Jy = 1.135;
Jz = 1.759;
Jxz = 0.1204;
G = Jx*Jz-Jxz^2;
G1 = Jxz*(Jx - Jy + Jz)/G;
G2 = (Jz*(Jz-Jy)+Jxz^2)/G;
G3 = Jz/G;
G4 = Jxz/G;
G5 = (Jz-Jx)/Jy;
G6 = Jxz/Jy;
G7 = ((Jx-Jy)*Jx +Jxz^2)/G;
G8 = (Jx/G);
p = 0;
q = 0;
r = 0;
l = 0.0000;
m = 0.0000;
n = 0.0000;
tspan = [0 10];
%[t,q] = ode45(@(t,q) (G5*p*r-G6*(p^2-r^2)+m/Jy), tspan,0);
%plot(t,q);
%pdot = (G1*p*q-G2*q*r + G3*l+G4*n);
[t,p]=ode45(@(t,p) (G1*p*q-G2*q*r+G3*l+G4*n),[0 10], 0.1);
plot(t,p,'--r');
disp(p);
disp(t);
[t,q] = ode45(@(t,r) (G5*p*r-G6*p*p-G6*r*r)+m/Jy), [0 10],0);
plot(t,q,'--g');
[t,r] = ode45(@(t,r) (G7*p*q-G1*q*r + G4*l+G8*n), [0 10],0);
plot(t,r,'--b')

Answer 1

[Voss]

You have an extra ")" here:

[t,q] = ode45(@(t,r) (G5*p*r-G6*p*p-G6*r*r)+m/Jy), [0 10],0);

% ^ extra parenthesis

That parenthesis closes the ode45 function call, leaving the rest of the line ", [0 10],0);" hanging out with nothing to do, and the closing parenthesis in that part causes the syntax error.

[DJ V]

Now it gives me the following error:

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0.1000

0

0.2500

0.5000

0.7500

1.0000

1.2500

1.5000

1.7500

2.0000

2.2500

2.5000

2.7500

3.0000

3.2500

3.5000

3.7500

4.0000

4.2500

4.5000

4.7500

5.0000

5.2500

5.5000

5.7500

6.0000

6.2500

6.5000

6.7500

7.0000

7.2500

7.5000

7.7500

8.0000

8.2500

8.5000

8.7500

9.0000

9.2500

9.5000

9.7500

10.0000

Error using *

Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the number of rows in the second matrix. To

perform elementwise multiplication, use '.*'.

Error in test>@(t,r)(G5*p*r-G6*p*p-G6*r*r+m/Jy) (line 30)

[t,q] = ode45(@(t,r) (G5*p*r - G6*p*p - G6*r*r + m/Jy), [0 10],0);

Error in odearguments (line 90)

f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in test (line 30)

[t,q] = ode45(@(t,r) (G5*p*r - G6*p*p - G6*r*r + m/Jy), [0 10],0);

[Voss]

If the original question is solved, please "Accept" this answer. Thanks!

Feel free to post a new question about error(s) you get running ode45.