subtreeprob, an operator is chosen from the function set funcset.
The operands are then generated by recursive calls. If no subtree is generated, a constant will
be generated with probability constprob. If no constant is generated, an input variable
will be chosen randomly. The depth of the resulting expression trees can be bounded by the
maxdepth parameter.
randexprFull creates a random full expression tree of depth maxdepth. The algorithm
is the same as randexprGrow, with the exception that the probability of generating
a subtree is fixed to 1 until the desired tree depth maxdepth is reached.
randexprGrow(funcset, inset, conset, maxdepth = 8, constprob = 0.2, subtreeprob = 0.5, curdepth = 1)
randexprFull(funcset, inset, conset, maxdepth = 8, constprob = 0.2)0.2.