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.
License: MIT
ubuntu2004
/* * Copyright (C) 2004 Bryant Lee * * This file is part of FProbPeriod. * * FProbPeriod 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 2 of the License, or * (at your option) any later version. * * FProbPeriod 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 FProbPeriod; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ /* This is the main function of the FProbPeriod program * FProbPeriod program samples points over N-shift that are shift periodic * with period k and finds period and preperiod. The result gives some * indication of what is the average period of all points of shift period k * over the N-shift. * * Written by: Bryant Lee * Date: 9/01/05 */ #define USEARRAYS 0 #define DEBUG 0 //Standard C++ #include <string.h> #include <iostream> #include <iomanip> #include <fstream> //for file ops //C #include <stdlib.h> //for atoi #include <math.h> //for pow, and ceil #include <time.h> //to get seed for random numbers //STL #include <vector> #include <list> #include <map> //local #include "StringOps.h" #include "Comp.h" #include "StorageKey.h" #include "StorageVal.h" #include "RecNode.h" #include "StorageKeyUInt.h" //mersenne twister, pseudo-random number generator #include "MTRand.h" //function definitions void convertPeriodList(const string &strInput, vector<int> &periodList); void probExp(unsigned int shiftSize, const vector<int> &periodList, Comp *comp, int numPoints, list<RecNode*> &recList, string &prefix, vector<string> &commandbuffer); void probExpTwoShift(const vector<int> &periodList, Comp *comp, int numPoints, list<RecNode*> &recList, string &prefix, vector<string> &commandbuffer); void clearStorageNodes(vector<StorageVal*> &table); void clearRecList(list<RecNode*> &recList); void output(unsigned int shiftSize, int numPoints, string &prefix, const vector<int> &periodList, Comp * comp, list<RecNode*> &recList, vector<string> &commandbuffer); void findDivisors(unsigned int x, vector<int> &divisorsList); bool leastPeriod(byte *word, unsigned int currPeriod, const vector<int> &divisorsList); bool leastPeriod(unsigned int word, unsigned int currPeriod, const vector<int> &divisorsList); //GLOBAL //this debug variable allows testing the "special case 2-shift" with //arrays of unsigned ints in which each unsigned int carries UINTSIZE //bits of info (each bit representing 1 coordinate). Values up to 32 allowed. int UINTSIZE = 32; //boolean that determines whether output is given after each completed experiment (after each K) //or only at end bool OUTPUT_AFTER_EACH = false; //main int main() { unsigned int shiftSize; //# symbols in shift string prefix; //prefix for output files string strInput, strInput2, strInput3; //temp variables vector<int> periodList; //list of periods unsigned int i = 0, temp; //counter list<RecNode*> recList; //list of records list<RecNode*> leastRecList; //list of records for points of least period k Comp *comp = NULL; //composition to apply int numPoints; string outoption; //hold the command strings vector<string> commandbuffer; int commandbufferit; //grab all input from cin and put in an array of strings while(!cin.eof()) { std::getline(cin, strInput); commandbuffer.push_back(strInput); } commandbufferit = 0; //get "output after each" or "output at end" outoption = commandbuffer[commandbufferit++]; trim(outoption); transform(outoption.begin(), outoption.end(), outoption.begin(), tolower); if(outoption == "output after each") OUTPUT_AFTER_EACH = true; else if(outoption == "output at end") OUTPUT_AFTER_EACH = false; else { cout << "Error on line 1: invalid value for output mode\n"; goto cleanup; } //get filename prefix prefix = commandbuffer[commandbufferit++]; trim(prefix); //get N, the number of symbols in the full shift strInput = commandbuffer[commandbufferit++]; trim(strInput); shiftSize = atoi(strInput.c_str()); //get set of K, the periodicities to be tested strInput = commandbuffer[commandbufferit++]; convertPeriodList(strInput, periodList); //get m, the number of sample points strInput = commandbuffer[commandbufferit++]; trim(strInput); numPoints = atoi(strInput.c_str()); //Allocate composition object comp = new Comp(shiftSize); //get "Begin Definitions" strInput = commandbuffer[commandbufferit++]; //make it lowercase trim(strInput); transform(strInput.begin(), strInput.end(), strInput.begin(), tolower); if(strInput.compare("begin definitions") != 0) { cout << "ERROR: Expecting \"BEGIN DEFINITIONS\"\n"; goto cleanup; } //read definitions while(1) { strInput = commandbuffer[commandbufferit++]; //strInput2 is lowercased and trimmed strInput2.resize(strInput.length()); transform(strInput.begin(), strInput.end(), strInput2.begin(), tolower); trim(strInput2); //strInput3 is lowercased and NOT TRIMMED strInput3.resize(strInput.length()); transform(strInput.begin(), strInput.end(), strInput3.begin(), tolower); if(strInput2 == "" || (strInput2[0] == '/' && strInput2[1] == '/')) { //ignore blank lines and allow comment out } else if(strInput2 == "begin commands") { break; //BREAK } else { i = 0; while(i < strInput.length()) { if(strInput[i] == '=') { break; } i++; } if(strInput2[0] == 'o' && strInput2[1] == 'p' && strInput2[2] == 't') { temp = strInput3.find("opt"); temp += 3; comp->addFunc(strInput.substr(i+1, strInput.length() - (i+1)), strInput.substr(temp, i-temp), true); } else { comp->addFunc(strInput.substr(i+1, strInput.length() - (i+1)), strInput.substr(0,i), false); } } } //read commands while(commandbufferit < (int)commandbuffer.size()) { //check for EOF strInput = commandbuffer[commandbufferit++]; trim(strInput); //ignore blank lines and allow comment out with "//" if(strInput != "" && !(strInput[0] == '/' && strInput[1] == '/')) { //set composition if(!comp->setComposition(strInput)) { cout << "ERROR: Command \"" << strInput << "\" references undefined function\n"; goto cleanup; } //do experiment if(shiftSize == 2 && sizeof(unsigned int) == 4 && !USEARRAYS) probExpTwoShift(periodList, comp, numPoints, recList, prefix, commandbuffer); else probExp(shiftSize, periodList, comp, numPoints, recList, prefix, commandbuffer); if(!OUTPUT_AFTER_EACH) output(shiftSize, numPoints, prefix, periodList, comp, recList, commandbuffer); //clear records (delete the nodes with ptrs in lists) clearRecList(recList); clearRecList(leastRecList); recList.clear(); leastRecList.clear(); } } //cleanup and exit cleanup: //delete the nodes with ptrs in lists clearRecList(recList); clearRecList(leastRecList); //delete composition (and the functions in the Comp object's storage) delete comp; return 0; } /* * Full output */ void output(unsigned int shiftSize, int numPoints, string &prefix, const vector<int> &periodList, Comp * comp, list<RecNode*> &recList, vector<string> &commandbuffer) { list<RecNode*>::const_iterator it; unsigned int commandbufferit = 0; if(DEBUG) cout << "Output\n"; //output ofstream fout; string fname = prefix + comp->returnName() + ".txt"; fout.open(fname.c_str(), ios::trunc | ios::out); if(!fout.is_open()) { cout << "ERROR: could not create file " << fname << "\n"; return; } //HEADER fout << "FProbPeriod 3.67\n"; /* fout << "N = " << shiftSize << "\n"; fout << "K = "; for(i = 0; i < periodList.size(); i++) { fout << periodList[i]; if(i != periodList.size() - 1) fout << ","; } fout << "\n"; fout << "m = " << numPoints << "\n"; */ fout << "\n"; //copy of the input fout << "INPUT\n"; fout << "--------------------\n"; for(commandbufferit = 0; commandbufferit < commandbuffer.size(); commandbufferit++) { string test; test = commandbuffer[commandbufferit]; trim(test); if(test != "") { fout << commandbuffer[commandbufferit] << "\n"; } } fout << "--------------------\n"; fout << "\n"; //file for preperiods ofstream fout_preperiod; string fname_preperiod = prefix + comp->returnName() + "_preperiods.txt"; fout_preperiod.open(fname_preperiod.c_str(), ios::trunc | ios::out); if(!fout_preperiod.is_open()) { cout << "ERROR: could not create file " << fname_preperiod << "\n"; return; } //HEADER fout_preperiod << "FProbPeriod 3.67\n"; /* fout_preperiod << "N = " << shiftSize << "\n"; fout_preperiod << "K = "; for(i = 0; i < periodList.size(); i++) { fout_preperiod << periodList[i]; if(i != periodList.size() - 1) fout_preperiod << ","; } fout_preperiod << "\n"; fout_preperiod << "m = " << numPoints << "\n"; */ fout_preperiod << "\n"; //copy of the input fout_preperiod << "INPUT\n"; fout_preperiod << "--------------------\n"; for(commandbufferit = 0; commandbufferit < commandbuffer.size(); commandbufferit++) { string test; test = commandbuffer[commandbufferit]; trim(test); if(test != "") { fout_preperiod << commandbuffer[commandbufferit] << "\n"; } } fout_preperiod << "--------------------\n"; fout_preperiod << "\n"; /* Output file */ //fill on right side, show in fixed notation fout << setiosflags(ios::left | ios::fixed); fout << "COMMAND:\n"; fout << comp->returnName() << "\n"; fout << "WITH DEFINITIONS:\n"; comp->printDefinitions(fout); fout << "\n"; /* Preperiod file */ //fill on right side, show in fixed notation fout_preperiod << setiosflags(ios::left | ios::fixed); fout_preperiod << "Preperiod output\n\n"; fout_preperiod << "COMMAND:\n"; fout_preperiod << comp->returnName() << "\n"; fout_preperiod << "WITH DEFINITIONS:\n"; comp->printDefinitions(fout_preperiod); fout_preperiod << "\n"; /* output file */ fout << "PERIOD K (NOT LEAST)\n\n"; /* preperiod file */ fout_preperiod << "PERIOD K (NOT LEAST)\n\n"; /* output file */ //Summary info fout << "K (AvgPd)^(1/K) (MaxPd)^(1/K) (AvgPrepd)^(1/K) (MaxPrepd)^(1/K)\n"; for(it = recList.begin(); it != recList.end(); it++) { fout << setw(3) << (*it)->currPeriod << " "; if((*it)->pending) { fout << "PENDING" << "\n"; } else { fout << setw(13) << setprecision(4) << pow((*it)->avgPeriod(),((double)1/((double)(*it)->currPeriod))) << " "; fout << setw(13) << setprecision(4) << pow((*it)->maxPeriod(),((double)1/(double)(*it)->currPeriod)) << " "; fout << setw(16) << setprecision(4) << pow((*it)->avgPreperiod(),((double)1/((double)(*it)->currPeriod))) << " "; fout << setw(16) << setprecision(4) << pow((*it)->maxPreperiod(), ((double)1/((double)(*it)->currPeriod))) <<"\n"; } } fout <<"\n"; fout << "K AvgPd MaxPd AvgPrepd MaxPrepd\n"; for(it = recList.begin(); it != recList.end(); it++) { fout << setw(3) << (*it)->currPeriod << " "; if((*it)->pending) { fout << "PENDING" << "\n"; } else { fout << setw(13) << setprecision(2) << (*it)->avgPeriod() << " "; fout << setw(13) << setprecision(2) << (*it)->maxPeriod() << " "; fout << setw(16) << setprecision(2) << (*it)->avgPreperiod() << " "; fout << setw(16) << setprecision(2) << (*it)->maxPreperiod() <<"\n"; } } //orbit and period multiplicity fout << "\n"; fout << "K Period Mult(#points)\n"; for(it = recList.begin(); it != recList.end(); it++) { fout << setw(3) << (*it)->currPeriod << " "; if((*it)->pending) { fout << "PENDING" << "\n"; } else { map<unsigned long long, unsigned long long>::const_iterator pitpoint; bool pfirst = true; //note that the period and orbit maps have the same periods in the same orders // so we can iterate through both at once for(pitpoint = (*it)->periodMap.begin(); pitpoint != (*it)->periodMap.end(); pitpoint++) { if(!pfirst) { fout << " "; } else { pfirst = false; } fout << setw(11) << pitpoint->first << " "; fout << setw(13) << pitpoint->second << "\n"; //points } } } /* Preperiod file */ //Preperiod multiplicity fout_preperiod << "K Preperiod Mult\n"; for(it = recList.begin(); it != recList.end(); it++) { fout_preperiod << setw(3) << (*it)->currPeriod << " "; if((*it)->pending) { fout_preperiod << "PENDING" << "\n"; } else { map<unsigned long long, unsigned long long>::const_iterator pit; bool pfirst = true; for(pit = (*it)->preperiodMap.begin(); pit != (*it)->preperiodMap.end(); pit++) { if(!pfirst) { fout_preperiod << " "; } else { pfirst = false; } fout_preperiod << setw(11) << pit->first << " "; fout_preperiod << setw(13) << pit->second << "\n"; } } } //DONE fout_preperiod.close(); fout.close(); } void probExp(unsigned int shiftSize, const vector<int> &periodList, Comp *comp, int numPoints, list<RecNode*> &recList, string &prefix, vector<string> &commandbuffer) { unsigned int i = 0; //k = 0; //counters unsigned long long j; unsigned int currPeriod; int point_it; map<StorageKey,unsigned long long> tree; //records points that we have seen list<RecNode*>::const_iterator recIterator; //initialize random number generator MTRand random; if(DEBUG) cout << "Arrays\n"; if(DEBUG) random.seed(2005); //hand seed //make a list of recNodes, one recNode per K value for(i =0; i < periodList.size(); i++) { recList.push_back(new RecNode(periodList[i], numPoints)); } //initialize recIterator recIterator = recList.begin(); //do for every K value for(i = 0; i < periodList.size(); i++) { currPeriod = periodList[i]; //record keeping RecNode *record = *recIterator; //start the sampled test for(point_it = 0; point_it < numPoints; point_it++) { byte cWord[currPeriod]; //curr word byte output[currPeriod]; //helper word unsigned long long period = 0, preperiod = 0; map<StorageKey,unsigned long long>::iterator rt; tree.clear(); //clear the tree //Set current word to random point for(j = 0; j < currPeriod; j++) { cWord[j] = random.randInt(shiftSize - 1); } //insert the first word into tree StorageKey sk1 = StorageKey(cWord, currPeriod); tree.insert(pair<StorageKey,unsigned long long>(sk1,0)); //DEBUG if(DEBUG >= 5) { cout << "\n\n-- Start orbit --\n"; printArray(cWord, currPeriod); } //Perform experiment j = 1; while(true) { comp->image(cWord, currPeriod, output); copyWord(cWord, output, currPeriod); //DEBUG if(DEBUG >= 5) printArray(cWord, currPeriod); StorageKey sk2 = StorageKey(cWord, currPeriod); rt = tree.find(sk2); if(rt != tree.end()) { break; } else { tree.insert(pair<StorageKey,unsigned long long>(sk2,j)); } j++; } period = j - rt->second; preperiod = rt->second; record->recordPeriod(period, preperiod); } record->pending = false; //advance recIterator to next in list recIterator++; if(OUTPUT_AFTER_EACH) { output(shiftSize, numPoints, prefix, periodList, comp, recList, commandbuffer); } } } void probExpTwoShift(const vector<int> &periodList, Comp *comp, int numPoints, list<RecNode*> &recList, string &prefix, vector<string> &commandbuffer) { unsigned int i = 0; unsigned long long j = 0; //k = 0; //counters unsigned int currPeriod; int point_it; map<StorageKeyUInt, unsigned long long> tree; list<RecNode*>::const_iterator recIterator; MTRand random; if(DEBUG) random.seed(2005); //hand seed if(DEBUG) cout << "Special case 2-shift\n"; for(i = 0; i < periodList.size(); i++) { recList.push_back(new RecNode(periodList[i], numPoints)); } recIterator = recList.begin(); for(i = 0; i < periodList.size(); i++) { unsigned int blocks; currPeriod = periodList[i]; blocks = (int) ceil( ((double)currPeriod) / ((double)UINTSIZE) ); if(DEBUG) { cout << "K = " << currPeriod << " blocks = " << blocks << "\n"; } RecNode *record = *recIterator; for(point_it = 0; point_it < numPoints; point_it++) { unsigned int cWord[blocks]; //curr word unsigned int output[blocks]; //helper word unsigned long long period = 0, preperiod = 0; map<StorageKeyUInt,unsigned long long>::iterator rt; //clear the tree tree.clear(); //set cWord to a random word //NOTE: it is very important to clear the array first or //else you may start out with junk for(j = 0; j < blocks; j++) { cWord[j] = 0; } int blocki = 0, offseti = 0; for(j = 0; j < currPeriod; j++) { cWord[blocki] |= (random.randInt(1) << (offseti)); offseti++; if(offseti >= UINTSIZE) { blocki++; offseti -= UINTSIZE; } } tree.insert(pair<StorageKeyUInt, unsigned long long>(StorageKeyUInt(cWord, blocks), 0)); //DEBUG if(DEBUG >= 5) { cout << "\n-- Start Orbit --\n"; printUIntArray(cWord, currPeriod); cout << "\n"; } //Perform experiment j = 1; while(true) { //NOTE: no need to clear output[]. Comp::image will automatically //initialize output[] to 0's and then fill it in. comp->image(cWord, currPeriod, output, blocks); copyUIntArray(cWord, output, blocks); //DEBUG if(DEBUG >= 5) { printUIntArray(cWord, currPeriod); cout << "\n"; } StorageKeyUInt sk(cWord,blocks); rt = tree.find(sk); if(rt != tree.end()) { break; } else { tree.insert(pair<StorageKeyUInt, unsigned long long>(sk, j)); } j++; } period = j - rt->second; preperiod = rt->second; record->recordPeriod(period, preperiod); } record->pending = false; //advance recIterator to next in list recIterator++; if(OUTPUT_AFTER_EACH) { output(2, numPoints, prefix, periodList, comp, recList, commandbuffer); } } } void convertPeriodList(const string &strInput, vector<int> &periodList) { vector<string> strList; //all terms vector<string> subList; //vector representation of an "[a,b]" term unsigned int strListLength = 0, i = 0; split(strInput,';', strList); strListLength = strList.size(); for(i = 0; i < strListLength; i++) { string *temp = &(strList[i]); trim(*temp); if((*temp)[0] == '[') { int j, low, high; temp->erase(0,1); //remove '[' temp->erase(temp->length() - 1, 1); //remove ']' split(*temp, ',', subList); trim(subList[0]); trim(subList[1]); low = atoi(subList[0].c_str()); high = atoi(subList[1].c_str()); for(j = low; j <= high; j++) { periodList.push_back(j); } subList.clear(); } else { periodList.push_back(atoi(temp->c_str())); } } } /* * Delete the nodes pointed to by ptrs in recList */ void clearRecList(list<RecNode*> &recList) { list<RecNode*>::iterator it; for(it = recList.begin(); it != recList.end(); it++) { delete (*it); } } /* * Delete the nodes pointed to by the values in the table */ void clearStorageNodes(vector<StorageVal*> &table) { vector<StorageVal*>::iterator it; for(it = table.begin(); it != table.end(); it++) { delete (*it); } } /* * Find divisors of X, excluding X itself */ void findDivisors(unsigned int x, vector<int> &divisorsList) { unsigned int i = 2; unsigned int halfX = x/2; divisorsList.clear(); if(x > 1) { divisorsList.push_back(1); } for(i = 2; i <= halfX; i++) { if(x % i == 0) { divisorsList.push_back(i); } } } /* * returns true if this word has least period p */ bool leastPeriod(byte *word, unsigned int currPeriod, const vector<int> &divisorsList) { bool result = false; unsigned int i, j, k; if(currPeriod == 1) return true; //for every divisor d for(i = 0; i < divisorsList.size(); i++) { unsigned int d = divisorsList[i]; result = false; //check in chunks of length d for(j = 0; j < currPeriod; j+= d) { //check that this chunk is same as other chunks for(k = 0; k < d; k++) { if(word[k + j] != word[k]) { result = true; break; } } if(result == true) break; } if(result == false) break; } return result; } /* * returns true if this word has least period p */ bool leastPeriod(unsigned int word, unsigned int currPeriod, const vector<int> &divisorsList) { bool result = false; unsigned int i, j, k; if(currPeriod == 1) return true; //for every divisor d for(i = 0; i < divisorsList.size(); i++) { unsigned int d = divisorsList[i]; result = false; //check in chunks of length d for(j = 0; j < currPeriod; j+= d) { //check that this chunk is same as other chunks for(k = 0; k < d; k++) { if(((word >> (k + j)) & 1) != ((word >> k) & 1)) { result = true; break; } } if(result == true) break; } if(result == false) break; } return result; }