config.go

// config.go implementation of configuration settings for NEAT.
//
// Copyright (C) 2017  Jin Yeom
//
// 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 <http://www.gnu.org/licenses/>.

package neat

import (
	"encoding/json"
	"fmt"
	"os"
	"text/tabwriter"
)

// Config consists of all hyperparameter settings for NEAT. It can be imported
// from a JSON file.
type Config struct {
	// general settings
	ExperimentName string `json:"experimentName"` // name of the experiment
	Verbose        bool   `json:"verbose"`        // verbose mode (terminal)

	// neural network settings
	NumInputs      int  `json:"numInputs"`      // number of inputs
	NumOutputs     int  `json:"numOutputs"`     // number of outputs
	FullyConnected bool `json:"fullyConnected"` // initially fully connected

	// evolution settings
	NumGenerations  int     `json:"numGenerations"`  // number of generations
	PopulationSize  int     `json:"populationSize"`  // size of population
	InitFitness     float64 `json:"initFitness"`     // initial fitness score
	MinimizeFitness bool    `json:"minimizeFitness"` // true if minimizing fitness
	SurvivalRate    float64 `json:"survivalRate"`    // survival rate
	StagnationLimit int     `json:"stagnationLimit"` // limit of stagnation

	// mutation rates settings
	RatePerturb     float64 `json:"ratePerturb"`     // by perturbing weights
	RateAddNode     float64 `json:"rateAddNode"`     // by adding a node
	RateAddConn     float64 `json:"rateAddConn"`     // by adding a connection
	RateMutateChild float64 `json:"rateMutateChild"` // mutation of a child

	// compatibility distance coefficient settings
	DistanceThreshold float64 `json:"distanceThreshold"` // distance threshold
	CoeffUnmatching   float64 `json:"coeffUnmatching"`   // unmatching genes
	CoeffMatching     float64 `json:"coeffMatching"`     // matching genes

	// CPPN settings
	CPPNActivations []string `json:"cppnActivations"` // additional activations
}

// NewConfigJSON creates a new instance of Config, given the name of a JSON file
// that consists of the hyperparameter settings.
func NewConfigJSON(filename string) (*Config, error) {
	f, err := os.Open(filename)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	config := &Config{}
	decoder := json.NewDecoder(f)
	if err = decoder.Decode(&config); err != nil {
		return nil, err
	}
	return config, nil
}

// Summarize prints the summarized configuration on terminal.
func (c *Config) Summarize() {
	w := tabwriter.NewWriter(os.Stdout, 40, 1, 1, ' ', tabwriter.TabIndent)
	fmt.Fprintf(w, "============================================\n")
	fmt.Fprintf(w, "Summary of NEAT hyperparameter configuration\t\n")
	fmt.Fprintf(w, "============================================\n")

	fmt.Fprintf(w, "General settings\t\n")
	fmt.Fprintf(w, "+ Experiment name\t%s\t\n", c.ExperimentName)
	fmt.Fprintf(w, "+ Verbose mode\t%t\t\n\n", c.Verbose)

	fmt.Fprintf(w, "Neural network settings\t\n")
	fmt.Fprintf(w, "+ Number of inputs\t%d\t\n", c.NumInputs)
	fmt.Fprintf(w, "+ Number of outputs\t%d\t\n", c.NumOutputs)
	fmt.Fprintf(w, "+ Fully connected\t%t\t\n\n", c.FullyConnected)

	fmt.Fprintf(w, "General evolution settings\t\n")
	fmt.Fprintf(w, "+ Number of generations\t%d\t\n", c.NumGenerations)
	fmt.Fprintf(w, "+ Population size\t%d\t\n", c.PopulationSize)
	fmt.Fprintf(w, "+ Initial fitness score\t%.3f\t\n", c.InitFitness)
	fmt.Fprintf(w, "+ Fitness is being minimized\t%t\t\n", c.MinimizeFitness)
	fmt.Fprintf(w, "+ Rate of survival each generation\t%.3f\t\n", c.SurvivalRate)
	fmt.Fprintf(w, "+ Limit of species' stagnation\t%d\t\n\n", c.StagnationLimit)

	fmt.Fprintf(w, "Mutation settings\t\n")
	fmt.Fprintf(w, "+ Rate of perturbation of weights\t%.3f\t\n", c.RatePerturb)
	fmt.Fprintf(w, "+ Rate of adding a node\t%.3f\t\n", c.RateAddNode)
	fmt.Fprintf(w, "+ Rate of adding a connection\t%.3f\t\n", c.RateAddConn)
	fmt.Fprintf(w, "+ Rate of mutating a child\t%.3f\t\n\n", c.RateMutateChild)

	fmt.Fprintf(w, "Compatibility distance settings\t\n")
	fmt.Fprintf(w, "+ Distance threshold\t%.3f\t\n", c.DistanceThreshold)
	fmt.Fprintf(w, "+ Unmatching connection genes\t%.3f\t\n", c.CoeffUnmatching)
	fmt.Fprintf(w, "+ Matching connection genes\t%.3f\t\n\n", c.CoeffMatching)

	fmt.Fprintf(w, "CPPN settings\t\n")
	fmt.Fprintf(w, "+ CPPN Activation functions\t%s\t\n", c.CPPNActivations)

	w.Flush()
}