How to define functions with constants?

msat59

Hi.

Is there any way to define a function with constants?

e.g.:

(a*x0 + b*x1*x2)^c

I think this feature is very useful to define flexible functions.

Thanks.

Mehdi

Dr. Candida Ferreira

Hi Mehdi,

You can define all kinds of functions with up to four arguments as Custom Functions or DDFs. Additionally you can use a seed model with a particular structure (like your example above) and then choose a fixed structure modeling strategy (you can do that by selecting certain genetic operators) and let evolution find a model for your data with that particular structure. Note however that constraining evolution in any way is usually not very effective.

Candida Ferreira

msat59

Hi Dr. Ferreira,

Is it possible to define a DDF exactly like my example? I'm not looking for (x0*x1 + x2*x3*x4)^x5 !

I thinks some new variables (e.g. c0, c1, c2....cn) should be defined in internal engine of GeneXproTools to define custom functions.

(c0*x0 + c1*x1*x2)^c3

When the program sees this function, it uses all possibilities for xn and only float numbers for cn variables.

Thanks.

Dr. Candida Ferreira

Hi Mehdi,

You can design custom functions with up to 4 inputs (arguments) in GeneXproTools (functions with more arguments are modeled by the algorithm itself as combinations of the basic functions or building blocks). The arguments to a function are evolvable, which means they can assume all possible combinations (constants, variables, all kinds of complex expressions), all fine-tuned by the learning algorithm so that a good fit is achieved.

Hope this helps.

Candida Ferreira

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