GPTIPS 2, Symbolic Regression. Error

Hi,

I'm using GPTIPS 2 (https://sites.google.com/site/gptips4matlab/) to come up with a model that fits some data. The code runs, and I get the pareto front of models etc. However, I’m getting an error related to the symbolic toolbox.

For instance, when using “gpmodelreport(gp,84)” I get a screen print saying “Simplifying model ...” and then, an error

Error using gpmodel2sym (line 103)

Could not get symbolic object(s) for this model. Error using sym>convertChar (line 1459)

Character vectors and strings in the first argument can only specify a variable or number. To evaluate character vectors and strings representing symbolic expressions, use ‘str2sym’.

That error also shows up when I do “comparemodelsREC”, “gpmodel2sym”, “uniquegenes”...

Any idea?

Cheers!

LJ

[Luis J Gilarranz]

I've narrowed down the error to the function gppretty.m, but substituting "sym" for "str2sym" doesn't solve the problem

Answer 1

[xox ir]

Hello,

please create this function:

function y=xsym(x)
if isnumeric(x)
    x=num2str(x);
end
y=str2sym(x);

Then add the code below:

if~verLessThan('matlab','9.3');sym=@xsym;end

At the begaining of gppretty.m

[Luis J Gilarranz]

Hi xox ir,

After following your instructions "gpmodelreport" works, however, when I want to use the gene browser to simplify the model I get the following error:

genes = uniquegenes(gp)

Scanning 100 models ...

Total encoded genes found: 373

Unique encoded genes found: 49

Decoding & simplifying genes...please wait.

Simplifying gene 1

Error using sym>convertChar (line 1459)

Character vectors and strings in the first

argument can only specify a variable or number. To

evaluate character vectors and strings

representing symbolic expressions, use 'str2sym'.

Error in sym>tomupad (line 1225)

S = convertChar(x);

Error in sym (line 214)

S.s = tomupad(x);

Error in uniquegenes (line 137)

symgenes{i} =

sym(genes.uniqueGenesDecoded{i});

Any idea?

Cheers,

LJ