73 lines
2 KiB
C++
73 lines
2 KiB
C++
/*
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* Copyright (C) 2005 Maarten Keijzer
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <eoSymMutate.h>
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#include <FunDef.h>
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#include <utils/eoRNG.h>
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using namespace std;
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std::pair<Sym, bool> do_mutate(Sym sym, double p, const LanguageTable& table) {
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bool changed = false;
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SymVec args = sym.args();
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if (rng.flip(p)) {
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token_t new_token = table.get_random_function(sym.token(), args.size());
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if (new_token != sym.token()) {
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changed = true;
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sym = Sym(new_token, args);
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}
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}
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for (unsigned i = 0; i < args.size(); ++i) {
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std::pair<Sym,bool> r = do_mutate(args[i], p, table);
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changed |= r.second;
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if (r.second)
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args[i] = r.first;
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}
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if (changed)
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return std::make_pair(Sym(sym.token(), args), true);
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// else
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return std::make_pair(sym, false);
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}
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// these two can (should?) move to an impl file
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bool mutate(Sym& sym, double p, const LanguageTable& table) {
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std::pair<Sym, bool> r = do_mutate(sym, p, table);
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sym = r.first;
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return r.second;
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}
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bool mutate_constants(Sym& sym, double stdev) {
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vector<double> values = get_constants(sym);
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if (values.empty()) {
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return false;
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}
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for (unsigned i = 0; i < values.size(); ++i) {
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values[i] += rng.normal() * stdev;
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}
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sym = set_constants(sym, values);
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return true;
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}
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