************************************************************************
TinyGA - v0.1.5
Created: 1/2012
Author: Alexander Hiam - ahiam@marlboro.edu - www.alexanderhiam.com
Website: https://github.com/alexanderhiam/TinyGA

A lightweight genetic algorithm library for Arduino microcontrollers.

Copyright (c) 2012 - Alexander Hiam 

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/>.
************************************************************************

Each individual is a single unsigned char. The user provides a fitness
function which takes an individual and returns an unsigned char fitness 
rating. A simple 'best-half' selection routine is used, where the best
scoring half of the population survives, then the rest of the population
is filled by randomly combining the surviving half. The combination
routine simply slices each pair of selected parents at one random
crossover point and returns a child which is made of one part of each 
parent. There is also a chance that each child will mutate randomly. 
The chance of mutation is user-defined in TinyGA.h.

A population can also be saved in the Arduino's EEPROM using the save() 
and load() methods. The population is saved in the form:

 Value:  key    key    key  population_size  generation   population--->
  Byte:  \0/    \1/    \2/    \3------4/      \5----7/     \8------->

where key is the value TINYGA_KEY in TinyGA.h which indicates that there
is a saved population when it is written to the first three bytes of the
EEPROM (starting at EEPROM_OFFSET).


API Usage:
 -TinyGA(uint8_t (*fitness_function)(uint8_t))
   Creates and returns an instance of the TinyGA class. Must be passed
   a user-defined function which takes an unsigned char individual and
   returns an unsigned char fitness rating. Fitnesses should range from
   0-255, where 0 is the worst rating and 255 indicates that the correct
   answer has been found and the algorithm should stop evolving. 

 -TinyGA.init(uint8_t population_size)
   Initialize a randomly generated population of the given size.

 -TinyGA.load(void)
   Attempts to load a population from the EEPROM. Returns 1 if successful,
   0 if there is no population in memory.

 -TinyGA.save(void)
   Attempts to save the current population. Returns 1 if successful,
   0 if the population size + EEPROM_OFFSET is greater than EEPROM_SIZE.

 -TinyGA.print(void)
   Prints the population size, current generation and the current 
   population to Serial. Serial.begin() must be called before hand.

 -TinyGA.reset(void)
   Resets to random population with current population size.
   The difference between reset() and init() for resetting the algorithm
   is that reset() will write over TINYGA_KEY in the EEPROM and init()
   won't effect the EEPROM.

 -TinyGA.reset(uint8_t new_population_size)
   Resets to random population with new population size. 
   Also resets EEPROM.

 -TinyGA.run(uint8_t n_generations)
   Runs the algorithm the given ammount of generations. Returns 0
   unless the fitness function has returned 255 indicating a correct
   answer, in which case the individual that scored 255 is returned.