MATLAB Answers

Error "using symengine>@()0.0" in ODE Solver

6 views (last 30 days)
Tom Keaton
Tom Keaton on 24 Aug 2019
Edited: Tom Keaton on 25 Aug 2019
Hello,
I restarted everything I did from scratch and in the most simpliest way possible to recreate the same error I get in my much larger code. This error occurs when I make the B-field components functions instead of constants as the E parts are currently defined in this specfiic example. However, in my much larger code this error occurs when I just change the syntax of the ode set so if this error can be resolved here, perhaps then I can figure out why it's happening in the larger code set.
Error:
Error using symengine>@()0.0
Too many input arguments.
Error in reffun (line 14)
ode1 = Ex + s(2).*Bz(s(4),s(5),s(6)) - s(3).*By(s(4),s(5),s(6));
Error in odearguments (line 90)
f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.
Error in ode15s (line 150)
odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
Error in diffiqtest (line 7)
[t,S] = ode15s(@reffun,tspan,s0);
Here is the main code:
v0 = [0 0 0];
p0 = [0 0 0];
s0 = [v0 p0];
tspan = [0 5];
[t,S] = ode15s(@reffun,tspan,s0);
Function where ODEs are defined:
function refsolve = reffun(t,s)
Ex = 0;
Ey = 0;
Ez = 0;
persistent Bx By Bz
%Used so that the B-field function is only run once
if isempty(Bx)
[Bx, By, Bz] = B_test();
end
%Reference: s(1) = vx, s(2) = vy, s(3) = vz, s(4) = x, s(5) = y, s(6) = z
ode1 = Ex + s(2).*Bz(s(4),s(5),s(6)) - s(3).*By(s(4),s(5),s(6));
ode2 = Ey + s(3).*Bx(s(4),s(5),s(6)) - s(1).*Bz(s(4),s(5),s(6));
ode3 = Ez + s(1).*By(s(4),s(5),s(6)) - s(2).*Bx(s(4),s(5),s(6));
ode4 = s(1);
ode5 = s(2);
ode6 = s(3);
refsolve = [ode1; ode2; ode3; ode4; ode5; ode6];
end
B_test function:
function [Bx, By, Bz] = B_test()
%Bfieldstrength = 0.64; %In (Teslas)
Bfieldstrength = 0;
magvol = 3.218E-6; %In (m)
mu0 = (4*pi)*10^-7;
magnetization = (Bfieldstrength*magvol)/mu0;
syms x y z
m = [0,0,magnetization];
r = [x, y, z];
B = mu0*(((dot(m,r)*r*3)/norm(r)^5) - m/norm(r)^3);
Bx = matlabFunction(B(1));
By = matlabFunction(B(2));
Bz = matlabFunction(B(3));
end

  0 Comments

Sign in to comment.

Accepted Answer

Walter Roberson
Walter Roberson on 24 Aug 2019
When you call matlabFunction pass
'vars', r

  6 Comments

Show 3 older comments
Tom Keaton
Tom Keaton on 24 Aug 2019
I see, but I still get the exact same error when I change it to this and clear reffun.
Tom Keaton
Tom Keaton on 25 Aug 2019
It is odd. Your files work, but mine do no even with the same definitions. Why is this the case? Also, when I try plotting the solution, it is incorrect, because I know the solution should not look the way it does. If the ode solver is not solving the equations correctly, and it is not outputting an error, what should I do in this sitatuon?

Sign in to comment.

More Answers (0)

Tags


Translated by