Ode45, Events error: SWITCH expression must be a scalar or a character vector

Question

Alice Bobbi 2023-11-30

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2054187-ode45-events-error-switch-expression-must-be-a-scalar-or-a-character-vector

编辑： Rena Berman 2023-12-5

Hi, I have this problem using "Events" option for ode45.

In the main I have:

Tol0 = 1e-13;
Tol1 = 1e-13;
options = odeset('Events', @myEvent, 'RelTol', Tol0, 'AbsTol', Tol1);
s0 = [1, 2, 3, 4, 5, 6];
tspan = [0 100];
[time,S] = ode45('Dyn', tspan, s0, options);

My event function is:

function [value, isterminal, direction] = myEvent(t,S)
value = S(2);
isterminal = 1;
direction = 0;
end

The error appearing in the command window is:

SWITCH expression must be a scalar or a character vector.

Error in odeevents (line 34)

switch lower(eventFcn)

Error in ode45 (line 137)

odeevents(odeIsFuncHandle,ode,t0,y0,options,varargin);

Error in Main (line 31)

[time,S] = ode45('Dyn', tspan, s0, options);

Could you help me?

Thank you.

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Alice Bobbi 2023-11-30

编辑：Alice Bobbi 2023-11-30

I didn't, thank you.

Rena Berman 2023-12-5

(Answers Dev) Restored edit

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Answer 1

Walter Roberson 2023-11-30

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2054187-ode45-events-error-switch-expression-must-be-a-scalar-or-a-character-vector#answer_1362872

在 MATLAB Online 中打开

I have seen this before when the person had a third-party version of lower in their MATLAB path. Please show

which -all lower
built-in (/MATLAB/toolbox/matlab/strfun/lower)
lower is a built-in method                                % string method
/MATLAB/toolbox/parallel/parallel/@codistributed/lower.m  % codistributed method

The interfering toolbox was something like EEGLab or SPM12 or something-or-other-8 (I forget the name)