Sym get_subtree(const Sym& cur, size_t w) {
if (w-- == 0) return cur;
const SymVec& vec = cur.args();
for (unsigned i = 0; i < vec.size(); ++i) {
if (w < vec[i].size()) return get_subtree(vec[i], w);
w-=vec[i].size();
}
return cur;
}
std::pair<Sym,bool> insert_subtree_impl(const Sym& cur, size_t w, const Sym& nw) {
if (w-- == 0) return make_pair(nw, !(nw == cur));
const SymVec& vec = cur.args();
std::pair<Sym,bool> result;
unsigned i;
for (i = 0; i < vec.size(); ++i) {
if (w < vec[i].size()) {
result = insert_subtree_impl(vec[i], w, nw);
if (result.second == false) return std::make_pair(cur, false); // unchanged
break;
}
w -= vec[i].size();
}
SymVec newvec = cur.args();
newvec[i] = result.first;
return make_pair(Sym(cur.token(), newvec), true);
}
/* finds and inserts the full code in a hashmap */
HashMap::iterator find_code(Sym sym, HashMap& map) {
HashMap::iterator result = map.find(sym);
if (result == map.end()) { // new entry
const SymVec& args = sym.args();
vector<string> argstr(args.size());
for (unsigned i = 0; i < args.size(); ++i) {
argstr[i] = find_code(args[i], map)->second;
}
// write out the code
const FunDef& fun = get_element(sym.token());
string code = fun.c_print(argstr, vector<string>());
result = map.insert( make_pair(sym, code) ).first; // only want iterator
}
return result;
}
HashMap::iterator find_entry(const Sym& sym, string& str, HashMap& map) {
HashMap::iterator result = map.find(sym);
if (result == map.end()) { // new entry
const SymVec& args = sym.args();
vector<string> argstr(args.size());
for (unsigned i = 0; i < args.size(); ++i) {
argstr[i] = find_entry(args[i], str, map)->second;
}
string var = make_var(map.size()); // map.size(): unique id
string code;
// write out the code
const FunDef& fun = get_element(sym.token());
code = fun.c_print(argstr, vector<string>() );
str += "double " + var + "=" + code + ";\n";
result = map.insert( make_pair(sym, var ) ).first; // only want iterator
}
return result;
}
std::pair<Sym, bool> do_mutate(Sym sym, double p, const LanguageTable& table) {
bool changed = false;
SymVec args = sym.args();
if (rng.flip(p)) {
token_t new_token = table.get_random_function(sym.token(), args.size());
if (new_token != sym.token()) {
changed = true;
sym = Sym(new_token, args);
}
}
for (unsigned i = 0; i < args.size(); ++i) {
std::pair<Sym,bool> r = do_mutate(args[i], p, table);
changed |= r.second;
if (r.second)
args[i] = r.first;
}
if (changed)
return std::make_pair(Sym(sym.token(), args), true);
// else
return std::make_pair(sym, false);
}