blt-gp/src/generators.cpp

183 lines
6.6 KiB
C++

/*
* <Short Description>
* Copyright (C) 2024 Brett Terpstra
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <blt/gp/generators.h>
#include <blt/gp/program.h>
#include <blt/std/logging.h>
#include <stack>
namespace blt::gp
{
// TODO: change how the generators work, but keep how nice everything is within the C++ file. less headers!
// maybe have tree call the generate functions with out variables as the members of tree_t
struct stack
{
blt::gp::operator_id id;
blt::size_t depth;
};
inline std::stack<stack> get_initial_stack(gp_program& program, type_id root_type)
{
std::stack<stack> tree_generator;
//
// auto& system = program.get_typesystem();
// // select a type which has a non-empty set of non-terminals
// type base_type;
// do
// {
// base_type = system.select_type(program.get_random());
// } while (program.get_type_non_terminals(base_type.id()).empty());
//
tree_generator.push(stack{program.select_non_terminal(root_type), 1});
return tree_generator;
}
template<typename Func>
inline tree_t create_tree(Func&& perChild, const generator_arguments& args)
{
std::stack<stack> tree_generator = get_initial_stack(args.program, args.root_type);
blt::size_t max_depth = 0;
tree_t tree;
while (!tree_generator.empty())
{
auto top = tree_generator.top();
tree_generator.pop();
auto& info = args.program.get_operator_info(top.id);
tree.get_operations().emplace_back(
info.function,
args.program.get_typesystem().get_type(info.return_type).size(),
top.id,
args.program.is_static(top.id));
max_depth = std::max(max_depth, top.depth);
if (args.program.is_static(top.id))
{
info.function(nullptr, tree.get_values(), tree.get_values());
continue;
}
for (const auto& child : info.argument_types)
std::forward<Func>(perChild)(args.program, tree_generator, child, top.depth + 1);
}
return tree;
}
tree_t grow_generator_t::generate(const generator_arguments& args)
{
return create_tree([args](gp_program& program, std::stack<stack>& tree_generator, type_id type, blt::size_t new_depth) {
if (new_depth >= args.max_depth)
{
if (program.get_type_terminals(type).empty())
tree_generator.push({program.select_non_terminal_too_deep(type), new_depth});
else
tree_generator.push({program.select_terminal(type), new_depth});
return;
}
if (program.get_random().choice() || new_depth < args.min_depth)
tree_generator.push({program.select_non_terminal(type), new_depth});
else
tree_generator.push({program.select_terminal(type), new_depth});
}, args);
}
tree_t full_generator_t::generate(const generator_arguments& args)
{
return create_tree([args](gp_program& program, std::stack<stack>& tree_generator, type_id type, blt::size_t new_depth) {
if (new_depth >= args.max_depth)
{
if (program.get_type_terminals(type).empty())
tree_generator.push({program.select_non_terminal_too_deep(type), new_depth});
else
tree_generator.push({program.select_terminal(type), new_depth});
return;
}
tree_generator.push({program.select_non_terminal(type), new_depth});
}, args);
}
population_t grow_initializer_t::generate(const initializer_arguments& args)
{
population_t pop;
for (auto i = 0ul; i < args.size; i++)
pop.get_individuals().emplace_back(grow.generate(args.to_gen_args()));
return pop;
}
population_t full_initializer_t::generate(const initializer_arguments& args)
{
population_t pop;
for (auto i = 0ul; i < args.size; i++)
pop.get_individuals().emplace_back(full.generate(args.to_gen_args()));
return pop;
}
population_t half_half_initializer_t::generate(const initializer_arguments& args)
{
population_t pop;
for (auto i = 0ul; i < args.size; i++)
{
if (args.program.get_random().choice())
pop.get_individuals().emplace_back(full.generate(args.to_gen_args()));
else
pop.get_individuals().emplace_back(grow.generate(args.to_gen_args()));
}
return pop;
}
population_t ramped_half_initializer_t::generate(const initializer_arguments& args)
{
auto steps = args.max_depth - args.min_depth;
auto per_step = args.size / steps;
auto remainder = args.size % steps;
population_t pop;
for (auto depth : blt::range(args.min_depth, args.max_depth))
{
for (auto i = 0ul; i < per_step; i++)
{
if (args.program.get_random().choice())
pop.get_individuals().emplace_back(full.generate({args.program, args.root_type, args.min_depth, depth}));
else
pop.get_individuals().emplace_back(grow.generate({args.program, args.root_type, args.min_depth, depth}));
}
}
for (auto i = 0ul; i < remainder; i++)
{
if (args.program.get_random().choice())
pop.get_individuals().emplace_back(full.generate(args.to_gen_args()));
else
pop.get_individuals().emplace_back(grow.generate(args.to_gen_args()));
}
blt_assert(pop.get_individuals().size() == args.size);
return pop;
}
}