Alternative way of defining a variable

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Saurabh Madankar
Saurabh Madankar 2021-10-19
回答： Walter Roberson 2021-10-19
Hello,
Is there any way I can define a variable without assigning it any value and not using syms?

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KSSV
KSSV 2021-10-19
a = zeros([],1) ;
b =[] ;
But it depends. What is the requirement?
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Walter Roberson
Walter Roberson 2021-10-19
Ran in:
str2sym('t')
ans = 
t
Does not directly use sym() or syms() . It uses sym() internally though.
Is the point that you need to be able to use piecewise() but for some reason you cannot use symbolic variables? Note that piecewise() is part of the symbolic toolbox, so if you have a restriction against using the symbolic toolbox then you cannot use piecewise()

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Walter Roberson
Walter Roberson 2021-10-19
https://www.mathworks.com/help/optim/ug/problem-based-workflow.html
Problem based optimization permits you to use optimvar() to define variables to be optimized over, without giving the variables specific values.
This probably satisfies your question as originally asked.
Unfortunately, piecewise() cannot be used with problem-based optimization.

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