Why does my code think I want to use the Symbolic Math Toolbox when in reality I want to solve a system of ODEs numerically?

I'm using MATLAB 2016a. I have a function that is called from the code's driver function. The called function has a line to solve a system of ODEs using ode45:

global TIME
global TORQUE I  %% TORQUE = [0 0 0]'  and  I = [1e-31 1e-31 1e-31]' initially.

%% The variables "spin", "axes" and "dt" below are passed from the driver function.

%%create one vector array that has the spin and axes 
y = reshape([spin' axes],1,12); %% [spin' axes] is a 3 x 4 matrix

t0 = TIME - dt; %% Initially, TIME = dt = 5.1e-5

%% Compute initial slopes
yp(1)     = (TORQUE(1) + y(2)*y(3)*(I(2)-I(3)))/I(1);
yp(2)     = (TORQUE(2) + y(3)*y(1)*(I(3)-I(1)))/I(2);
yp(3)     = (TORQUE(3) + y(1)*y(2)*(I(1)-I(2)))/I(3);
yp(4:6)   = y(3)*y(7:9) - y(2)*y(10:12);
yp(7:9)   = y(1)*y(10:12) - y(3)*y(4:6);
yp(10:12) = y(2)*y(4:6) - y(1)*y(7:9);

%% create function handle to euler, which contains ODEs
fun=@euler;  

%% Set integration parameters
tmp={'RelTol' 'AbsTol' 'MinStep' 'MaxStep' 'NextStep' ...
'SafetyFactor' 'GrowthLimit' 'ShrinkLimit' 'FallBack'
1e-5     1e-8      .001*dt      dt         nan    ...
0.9            5              0.1        'on'};
params=struct(tmp{:});

%% Call integrator
[t,y] = ode45(fun,[t0, t0 + dt],yp,params)

When I execute the code, it stops at the ode45 line and produces the following messages:

Any insight into why this is happening would be appreciated.

Answer 1

[Stephen23]

Take a look at these two lines:

%% create function handle to euler, which contains ODEs
fun=@euler;

euler is in the symbolic toolbox:

https://www.mathworks.com/help/symbolic/euler.html

Based on your comment you seemed to think that you were calling another function.

[Augusto C]

That was it! I hadn't realized "euler" was part of the Symbolic Toolbox. Those error messages are now gone. Thank you.