Simulink isn't letting me uses the syms command.

Question

Christopher Shober 2022-12-2

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1869082-simulink-isn-t-letting-me-uses-the-syms-command

回答： Vidip Jain 2023-3-20

This is the function block from simulink. I am trying to solve for xr symbolically and then use that value to solve for other values. When I run the script it tells me that "Function 'syms' not supported for code generation.". I tried using the coder.extrinsic command and running it from a .m file, but it wasn't working that way either. Thank you in advance.

function error = errorfcn(Xc,Yc)

syms xr

yr=0.005*xr^2

D1=((((xr-Xc)^2)+(yr-Yc)^2)^.5);

dp2=diff(D1,xr)

xnew=solve(dp2==0,xr)

ynew=0.005*xr^2

D2=((((xnew-Xc)^2)+((ynew-Yc)^2))^.5)

if xnew > xr

error = D2

else

error = -1*D2

end

Here is the coder.extrinsic line that I tried running too:

function error = errorfcn(Xc, Yc)

coder.extrinsic(' errorfcn');

error = errorfcn (Xc,Yc);

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Answer 1

Vidip Jain 2023-3-20

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1869082-simulink-isn-t-letting-me-uses-the-syms-command#answer_1196855

The error message you received indicates that the syms function is not supported for code generation, meaning that it cannot be used to generate C/C++ code from your Simulink model.

One potential solution to this issue is to use the sym function instead of syms to define xr as a symbolic variable. The sym function creates a symbolic variable with a specified name and data type, and can be used for code generation.

Note that the solve function is also not supported for code generation. If you need to solve equations symbolically, you may need to find an alternative approach that is supported for code generation, such as using the fsolve function to numerically solve for the root of an equation.