CoCalc -- StorageKey.h

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A (one dimensional) cellular automaton is a function1 F : Σ → Σ with the property that there is a K > 0 such that F (x)i depends only on the 2K + 1 coordinates xi−K , xi−K+1, . . . , xi−1, xi, xi+1, . . . , xi+K . A periodic point of σ is any x such that σ^p (x) = x for some p ∈ N, and a periodic point of F is any x such that F^q (x) = x for some q ∈ N. Given a cellular automaton F, a point x ∈ Σ is jointly periodic if there are p, q ∈ N such that σ^p (x) = F^q (x) = x, that is, it is a periodic point under both functions.

This project aims to explore the nature of one-dimensional Cellular Automata, in the hope of finding the structure of cellular automata through its periodic points.

Shared Project -- M498ES23-Cellular-Automata

LEMMA Research Project / Code / Source code / Program (1) / Program / Source / StorageKey.h

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License: MIT
ubuntu2004

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/*
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 * Copyright (C) 2004 Bryant Lee
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 *
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 * This file is part of FPeriod.
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 *
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 * FPeriod is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * FPeriod 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 FPeriod; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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 */
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/*
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 * StorageKey
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 * Node with a word member.  Comparisons are allowed and are according
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 * to lexicographic order of the words.
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 *
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 * Written by: Bryant Lee
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 * Date: 11/4/04
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 */
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#ifndef STORAGE_KEY_H
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#define STORAGE_KEY_H
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#define byte unsigned char
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class StorageKey {
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 public:
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  byte * word;
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 private:
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  unsigned int wordLength;
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  //compare
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  //if > m, return positive
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  //if < m, return negative
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  //if == m, return 0
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  int compareTo(const StorageKey &m) const;
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 public:
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  //no argument constructor
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  StorageKey();
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  //primary constructor
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  StorageKey(byte *inWord, unsigned int inLength);
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  //copy constructor
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  StorageKey(const StorageKey &m);
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  //destructor
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  ~StorageKey();
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  //operator =
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  const StorageKey & operator=(const StorageKey &right);
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  //relational operators
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  bool operator==(const StorageKey &right) const;
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  bool operator!=(const StorageKey &right) const;
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  bool operator<(const StorageKey &right) const;
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  bool operator>(const StorageKey &right) const;
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  bool operator<=(const StorageKey &right) const;
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  bool operator>=(const StorageKey &right) const;
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  //print
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  void print() const;
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  /*
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   * This hash actually puts the 0th element at the lsb, then moves left.
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   * Since in the FPeriod program, 0 is actually on the left, this is
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   * somewhat "backwards".
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   */
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  unsigned long long hash(unsigned int shiftSize) {
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    unsigned int i; 
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    unsigned long long result = 0;
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    unsigned int power = 1;
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    for(i = 0; i < wordLength; i++) {
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      result += power * word[i];
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      power *= shiftSize;
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    }
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    return result;
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  }
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  /*
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   * This hash puts the 0th element at the msb and moves right.
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   * Essentially, elements hash to their baseB representation where
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   * B = shiftSize
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   */
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  unsigned long long hash_baseB(unsigned int shiftSize) {
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    int i;
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    unsigned long long result = 0;
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    unsigned int power = 1;
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    for(i = wordLength - 1; i >= 0; i--) {
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      result += power * word[i];
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      power *= shiftSize;
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    }
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    return result;
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  }
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};
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#endif
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