blt-gp/include/blt/gp/program.h

320 lines
12 KiB
C++

#pragma once
/*
* 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/>.
*/
#ifndef BLT_GP_PROGRAM_H
#define BLT_GP_PROGRAM_H
#include <cstddef>
#include <functional>
#include <type_traits>
#include <string_view>
#include <string>
#include <utility>
#include <iostream>
#include <random>
#include <algorithm>
#include <blt/std/ranges.h>
#include <blt/std/hashmap.h>
#include <blt/std/types.h>
#include <blt/std/utility.h>
#include <blt/std/memory.h>
#include <blt/gp/fwdecl.h>
#include <blt/gp/typesystem.h>
#include <blt/gp/operations.h>
#include <blt/gp/tree.h>
#include <blt/gp/stack.h>
namespace blt::gp
{
struct argc_t
{
blt::u32 argc = 0;
blt::u32 argc_context = 0;
};
struct config_t
{
// number of times crossover will try to pick a valid point in the tree. this is purely based on the return type of the operators
blt::u16 max_crossover_tries = 5;
// if we fail to find a point in the tree, should we search forward from the last point to the end of the operators?
bool should_crossover_try_forward = false;
};
struct operator_info
{
std::vector<type_id> argument_types;
type_id return_type;
argc_t argc;
detail::callable_t function;
detail::transfer_t transfer;
};
struct operator_storage
{
// indexed from return TYPE ID, returns index of operator
blt::expanding_buffer<std::vector<operator_id>> terminals;
blt::expanding_buffer<std::vector<operator_id>> non_terminals;
blt::expanding_buffer<std::vector<std::pair<operator_id, blt::size_t>>> operators_ordered_terminals;
// indexed from OPERATOR ID (operator number)
blt::hashset_t<operator_id> static_types;
// blt::expanding_buffer<std::vector<type>> argument_types;
// blt::expanding_buffer<argc_t> operator_argc;
// std::vector<detail::callable_t> operators;
// std::vector<detail::transfer_t> transfer_funcs;
std::vector<operator_info> operators;
};
template<typename Context = detail::empty_t>
class operator_builder
{
friend class gp_program;
friend class blt::gp::detail::operator_storage_test;
public:
explicit operator_builder(type_provider& system): system(system)
{}
template<typename Return, typename... Args>
operator_builder& add_operator(const operation_t<Return(Args...)>& op, bool is_static = false)
{
auto return_type_id = system.get_type<Return>().id();
auto operator_id = blt::gp::operator_id(storage.operators.size());
auto& operator_list = op.get_argc() == 0 ? storage.terminals : storage.non_terminals;
operator_list[return_type_id].push_back(operator_id);
operator_info info;
if constexpr (sizeof...(Args) > 0)
{
(add_non_context_argument<Args>(info.argument_types), ...);
}
info.argc.argc_context = info.argc.argc = sizeof...(Args);
info.return_type = system.get_type<Return>().id();
((std::is_same_v<detail::remove_cv_ref<Args>, Context> ? info.argc.argc -= 1 : (blt::size_t) nullptr), ...);
BLT_ASSERT(info.argc.argc_context - info.argc.argc <= 1 && "Cannot pass multiple context as arguments!");
info.function = op.template make_callable<Context>();
info.transfer = [](stack_allocator& to, stack_allocator& from) {
#if BLT_DEBUG_LEVEL >= 3
auto value = from.pop<Return>();
BLT_TRACE_STREAM << value << "\n";
to.push(value);
#else
to.push(from.pop<Return>());
#endif
};
storage.operators.push_back(info);
if (is_static)
storage.static_types.insert(operator_id);
return *this;
}
operator_storage&& build()
{
blt::hashset_t<type_id> has_terminals;
for (const auto& v : blt::enumerate(storage.terminals))
{
if (!v.second.empty())
has_terminals.insert(v.first);
}
for (const auto& op_r : blt::enumerate(storage.non_terminals))
{
if (op_r.second.empty())
continue;
auto return_type = op_r.first;
std::vector<std::pair<operator_id, blt::size_t>> ordered_terminals;
for (const auto& op : op_r.second)
{
// count number of terminals
blt::size_t terminals = 0;
for (const auto& type : storage.operators[op].argument_types)
{
if (has_terminals.contains(type))
terminals++;
}
ordered_terminals.emplace_back(op, terminals);
}
bool found_terminal_inputs = false;
bool matches_argc = false;
for (const auto& terms : ordered_terminals)
{
if (terms.second == storage.operators[terms.first].argc.argc)
matches_argc = true;
if (terms.second != 0)
found_terminal_inputs = true;
if (matches_argc && found_terminal_inputs)
break;
}
if (!found_terminal_inputs)
BLT_ABORT(("Failed to find function with terminal arguments for return type " + std::to_string(return_type)).c_str());
if (!matches_argc)
{
BLT_ABORT(("Failed to find a function which purely translates types "
"(that is all input types are terminals) for return type " + std::to_string(return_type)).c_str());
}
std::sort(ordered_terminals.begin(), ordered_terminals.end(), [](const auto& a, const auto& b) {
return a.second > b.second;
});
auto first_size = *ordered_terminals.begin();
auto iter = ordered_terminals.begin();
while (++iter != ordered_terminals.end() && iter->second == first_size.second)
{}
ordered_terminals.erase(iter, ordered_terminals.end());
storage.operators_ordered_terminals[return_type] = ordered_terminals;
}
return std::move(storage);
}
private:
template<typename T>
void add_non_context_argument(decltype(operator_info::argument_types)& types)
{
if constexpr (!std::is_same_v<Context, detail::remove_cv_ref<T>>)
{
types.push_back(system.get_type<T>().id());
}
}
type_provider& system;
operator_storage storage;
};
class gp_program
{
public:
/**
* Note about context size: This is required as context is passed to every operator in the GP tree, this context will be provided by your
* call to one of the evaluator functions. This was the nicest way to provide this as C++ lacks reflection
*
* @param system type system to use in tree generation
* @param engine random engine to use throughout the program. TODO replace this with something better
* @param context_size number of arguments which are always present as "context" to the GP system / operators
*/
explicit gp_program(type_provider& system, std::mt19937_64 engine):
system(system), engine(engine)
{}
void generate_tree();
[[nodiscard]] inline std::mt19937_64& get_random()
{
return engine;
}
[[nodiscard]] inline bool choice()
{
static std::uniform_int_distribution dist(0, 1);
return dist(engine);
}
/**
* @param cutoff precent in floating point form chance of the event happening.
* @return
*/
[[nodiscard]] inline bool choice(double cutoff)
{
static std::uniform_real_distribution dist(0.0, 1.0);
return dist(engine) < cutoff;
}
[[nodiscard]] inline type_provider& get_typesystem()
{
return system;
}
inline operator_id select_terminal(type_id id)
{
// we wanted a terminal, but could not find one, so we will select from a function that has a terminal
if (storage.terminals[id].empty())
return select_non_terminal_too_deep(id);
std::uniform_int_distribution<blt::size_t> dist(0, storage.terminals[id].size() - 1);
return storage.terminals[id][dist(engine)];
}
inline operator_id select_non_terminal(type_id id)
{
std::uniform_int_distribution<blt::size_t> dist(0, storage.non_terminals[id].size() - 1);
return storage.non_terminals[id][dist(engine)];
}
inline operator_id select_non_terminal_too_deep(type_id id)
{
std::uniform_int_distribution<blt::size_t> dist(0, storage.operators_ordered_terminals[id].size() - 1);
return storage.operators_ordered_terminals[id][dist(engine)].first;
}
inline operator_info& get_operator_info(operator_id id)
{
return storage.operators[id];
}
inline std::vector<operator_id>& get_type_terminals(type_id id)
{
return storage.terminals[id];
}
inline std::vector<operator_id>& get_type_non_terminals(type_id id)
{
return storage.non_terminals[id];
}
inline bool is_static(operator_id id)
{
return storage.static_types.contains(static_cast<blt::size_t>(id));
}
inline void set_operations(operator_storage&& op)
{
storage = std::move(op);
}
[[nodiscard]] inline const config_t& get_config() const
{
return config;
}
private:
type_provider& system;
blt::gp::stack_allocator alloc;
config_t config;
operator_storage storage;
std::mt19937_64 engine;
};
}
#endif //BLT_GP_PROGRAM_H