How to stop a future modification in matlab sym function

Hi all,

I have been using the symbolic toolbox for a while. I needed to create a symbolic function for an expected value. As matlab does not, at least for now, allow defining properties of arbitrary functions such as:

E(a+b)=E(a)+E(b)

or

E(k*eps)=k*E(eps)

(nor it allows defining variables and constants separately)

I've decided to go and transform my symbolic variable into char, use regular expressions, and then bring it back to symbolic. As I was doing so (the whole process works pretty well), as I ran the code:

result_symbolic=sym(result_char)

I received the following message:

"Warning: Support of character vectors that are not valid variable names or define a number will be removed in a future release. To create symbolic expressions, first create symbolic variables and then use operations on them. "

How can I make them know that there are cases in which it is not possible to actually manually create symbolic, like in the cases there I have worked on?

Answer 1

[Walter Roberson]

You create a Technical Support case and present your use case.

... Probably they will refer you to the new str2sym() function.

[Raphael Chinchilla]

Thanks! The function str2sym() was probably introduced in the 2017b and as I am running the 2017a I cannot check whether they have the same behavior.

[Walter Roberson]

str2sym() was introduced in R2017b.

What you are doing will continue to work in R2017a and R2017b, but after that will likely fail.