Alternative way of defining a variable

Hello,

Is there any way I can define a variable without assigning it any value and not using syms?

[KSSV]

In what contest? What is the requirement?

Answer 1

[KSSV]

a = zeros([],1) ;
b =[] ;

But it depends. What is the requirement?

[Saurabh Madankar]

I need to define a piecewise function without using sym to define the variable

[KSSV]

How about anonymous fnctions ?

[Walter Roberson]

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()

Answer 2

[Walter Roberson]

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.