Alternative to EVAL string expressions in optimization

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Kylekk 2022-5-30

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评论： Kylekk 2022-5-31

Hi,

I have a huge matrix, each element is a string like "16*q^2+4*q", i call it new_sol_array, now i want to define multiple optimconstr object with each row one set of constraints. This is what i did:

constr= optimconstr(M,N);

for i=1:rows

for j =1:column

constr(i,j)=eval(new_sol_array(i,j)+'==0');

end

As you would see, this is extremely slow. Is there a better alternative to do the same thing? i have read some of the answers about eval on this website yet did not find anything relevant enough to my problem.

Thank you so much!!!

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采纳的回答

Walter Roberson 2022-5-31

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Instead of eval() everything, use file operations to emit a file along the lines of

constr = [
   EQN, EQN,... EQN
   EQN, EQN,... EQN
]

along with a function header. Then "clear" the name of the file. Then invoke the file as a function passing in q and whatever else is required

This reduces the burden by not needing to eval() each one individually.

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Stephen23 2022-5-31

编辑：Stephen23 2022-5-31

Did you try writing a function file and calling it, as Walter Roberson described?

Kylekk 2022-5-31

Thank you Stephen, I did not do that simply because I don't get the idea. What kind of function file are you talking about? I have only a string array, why would a function takes variable names as input help?

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