Error in sym: Character vectors and strings in the first argument can only specify a variable or number.

I'm using GPTIPS to develop a model that fits my data.I'm using R2020a.

I am trying to run gpdemo1,gpdemo2,gpdemo3,gpdemo4 but facing an error whose screenshot I have attached.

Any Idea??

Answer 1

[Steven Lord]

As of release R2018a, calling sym with a char input that is not a valid variable name or a number will error. Modify the code so it calls sym to create symbolic variables or symboli numbers and assemble the symbolic expression by operating on those symbolic variables or numbers or use str2sym to convert the text expression into a symbolic expression.