zverify_df.cpp

这是一种很好的SAT解析器。通过它

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#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include <cstdio>
#include <vector>
#include <set>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <assert.h>

using namespace std;

#define WORD_LEN 64000

#define MEM_LIMIT 800000

#define UNKNOWN 2

int _peak_mem;
bool _dump_core; 

double get_cpu_time()
{
    double res;
    struct rusage usage;

    getrusage(RUSAGE_SELF, &usage);

    res = usage.ru_utime.tv_usec + usage.ru_stime.tv_usec;
    res *= 1e-6;
    res += usage.ru_utime.tv_sec + usage.ru_stime.tv_sec; 
	
    return res;
}

void get_line(ifstream &fs, vector<char> &buf)
{
    buf.clear();
    buf.reserve(4096);
    while(!fs.eof()) {
        char ch = fs.get();
        if(ch == '\n' || ch == '\377')
	    break;
        if(ch == '\r') 
	    continue;
        buf.push_back(ch);
    }
    buf.push_back('\0');
    return;
}

int get_token (char * & lp, char * token)
{
    char * wp = token;
    while (*lp && ((*lp == ' ') || (*lp == '\t'))) {
	lp++;
    }
    while (*lp && (*lp != ' ') && (*lp != '\t') && (*lp != '\n')) {
	*(wp++) = *(lp++);
    }
    *wp = '\0';                                 // terminate string
    return wp - token; 
}

int get_mem_usage(void) 
{
    FILE * fp;
    char buffer[128];
    char token[128];
    char filename[128];

    int pid = getpid();
    sprintf(filename, "/proc/%i/status", pid);
    if ( (fp = fopen (filename, "r")) == NULL) {
	cerr << "Can't open Proc file, are you sure you are using Linux?" << endl;
	exit(1);
    }
    while(!feof(fp)) {
	fgets(buffer, 128, fp);
	char * ptr = buffer;
	get_token(ptr, token);
	if (strcmp(token, "VmSize:")==0) {
	    get_token(ptr, token);
	    fclose(fp);
	    return atoi(token);
	}
    }
    cerr << "Error in get memeory usage" << endl;
    exit(1);
    return 0;
}

int my_a2i(char * str)
{
    int result = 0;
    bool neg = false;
    if (str[0] == '-') {
	neg = true;
	++ str;
    }
    else if (str[0] == '+')
	++ str;
    for (unsigned i=0; i< strlen(str); ++i) {
	int d = str[i] - '0';
	if (d < 0 || d > 9) {
	    cerr << "Abort: Unable to change " << str << " into a number " << endl;
	    exit(1);
	}
	result = result * 10 + d;
    }
    if (neg) 
	result = -result;
    return result;
}

class CClause 
{
public:    
    vector<int> literals;
//      vector<int> my_literals;
    vector<int> resolvents;
//      bool my_is_built;
    bool is_involved	: 1;
    bool is_built	: 1;	
    bool is_needed	: 1;
public:
    CClause(void) {
	is_involved = false;
	is_built = false;
	is_needed = false;
//  	my_is_built = false;
    }
    ~CClause(){}
};

class CVariable
{
public:
    short value;
    short in_clause_phase	:4; 
    bool is_needed		:1;
    int antecedent;
    int num_lits[2];
    int level;
    CVariable(void) { 
	value = UNKNOWN; 
	antecedent = -1; 
	in_clause_phase = UNKNOWN;
	num_lits[0] = num_lits[1] = 0;
	level = -1;
	is_needed = false;
    }
};
struct cmp_var_level 
{
    bool operator () (CVariable * v1, CVariable * v2)
	{
	    if (v1->level > v2->level)
		return true;
	    else if (v1->level < v2->level)
		return false;
	    else if ( (int)v1 > (int)v2)
		return true;
	    return false;
	}
};

class CDatabase {
private:
    int _current_num_clauses;

    int	_num_init_clauses;

    vector<CVariable> _variables;

    vector<CClause> _clauses;

    int _conf_id;

    vector<int> _conf_clause;

public:
    CDatabase() {
	_num_init_clauses = 0;
	_current_num_clauses = 0;
	_conf_id = -1;
    }

    int & num_init_clauses(void) { return _num_init_clauses; }

    vector<CVariable> & variables(void) {return _variables; }

    vector<CClause> & clauses(void)  {return  _clauses; }
    
    void read_cnf(char * filename);

    bool verify(char * filename);

    bool real_verify(void);

    int lit_value(int svar) { 
	assert (_variables[svar>>1].value != UNKNOWN);
	return _variables[svar>>1].value ^ (svar&0x1);
    }

    int add_orig_clause_by_lits(vector<int> lits);
	
    int add_learned_clause_by_resolvents(vector<int> & resolvents);

    void set_var_number(int nvar);

    void set_init_cls_number (int n) {
	_num_init_clauses = n;
    }
    void construct_learned_clauses(void);

    void recursive_construct_clause(int cl_id);

    void recursive_find_involved (int cl_id);

    int recursive_find_level(int vid);
    
    void dump(void);
};

void CDatabase::dump(void) 
{
    cout << "p cnf " << _variables.size() - 1 << " " << _num_init_clauses << endl;
    for (unsigned i=0; i< _clauses.size(); ++i) {
	for (unsigned j=0; j< _clauses[i].literals.size(); ++j ) {
	    int lit = _clauses[i].literals[j];
	    cout << ((lit & 0x1)?"-":"") << (lit>>1) << " ";
	}
	cout << "0" << endl;
    }
}
void CDatabase::set_var_number(int nvar) 
{ 
    _variables.resize(nvar + 1);
    for (unsigned i=0; i < _variables.size(); ++i) {
	_variables[i].value = UNKNOWN;
	_variables[i].in_clause_phase = UNKNOWN;
    }
}

void check_mem_out(void)
{
    int mem = get_mem_usage();
    if (mem > MEM_LIMIT) {
	cerr << "Mem out" << endl;
	exit(1);
    }
    if (mem > _peak_mem)
	_peak_mem = mem;
}

int CDatabase::add_orig_clause_by_lits(vector<int> lits) 
{
    static int line_n = 0;
    ++ line_n;
    if (lits.size() == 0) {
	cerr << "Empty Clause Encountered " << endl;
	exit(1);
    }
    int cls_id = _clauses.size();
    _clauses.resize(_clauses.size() + 1);
    vector<int> temp_cls;
    for (unsigned i=0; i< lits.size(); ++i) {
	int vid = lits[i];
	int phase = 0;
	if (vid < 0) {
	    vid = - vid;
	    phase = 1;
	}
	if (vid == 0 || vid > (int) _variables.size() - 1) {
	    cerr << "Variable index out of range " << endl;
	    exit(1);
	}
	if (_variables[vid].in_clause_phase == UNKNOWN){
	    _variables[vid].in_clause_phase = phase;
	    temp_cls.push_back(vid + vid + phase);
//  	    _clauses[cls_id].my_literals.push_back(vid + vid + phase);
	    ++ _variables[vid].num_lits[phase];
	}
	else if (_variables[vid].in_clause_phase != phase) {
	    cerr << "clause " << line_n << endl;
	    cerr << "A clause contain both literal and its negate " << endl;
	    exit(1);
	}
    }
    _clauses[cls_id].literals.resize(temp_cls.size());
    for (unsigned i=0; i< temp_cls.size(); ++i) {
	_clauses[cls_id].literals[i]= temp_cls[i];
    }
    _clauses[cls_id].is_built = true;
//      _clauses[cls_id].my_is_built = true;
    for (unsigned i=0; i< lits.size(); ++i) {
	int vid = lits[i];
	if (vid < 0) vid = -vid;
	_variables[vid].in_clause_phase = UNKNOWN;
    }
    ++ _current_num_clauses;
    if (_current_num_clauses%10 == 0)
	check_mem_out();
    return cls_id;
}

int CDatabase::add_learned_clause_by_resolvents(vector<int> & resolvents)
{
    int cls_id = _clauses.size();
    _clauses.resize(_clauses.size() + 1);
    _clauses[cls_id].resolvents.resize(resolvents.size());
    for (unsigned i=0; i< resolvents.size();  ++i) 
	_clauses[cls_id].resolvents[i] = resolvents[i];
    _clauses[cls_id].is_built = false;
    return cls_id;
}

void CDatabase::read_cnf (char * filename)
{
    cout << "Read in original clauses ... ";
    ifstream in_file (filename);
    if (!in_file) {
	cerr << "Can't open input CNF file " << filename << endl;
	exit(1);
    }
    vector<char> buffer;
    vector<int> literals;
    bool header_encountered = false;
    char token[WORD_LEN];	
    while (!in_file.eof()) {
	get_line(in_file, buffer);
	char * ptr = &(*buffer.begin());
	if (get_token(ptr, token)) {
	    if (strcmp(token, "c")==0)
		continue;
	    else if (strcmp(token, "p")==0) {
		get_token(ptr, token);
		if (strcmp(token, "cnf") != 0) {
		    cerr << "Format Error, p cnf NumVar NumCls " << endl;
		    exit(1);
		}
		get_token(ptr, token);
		int nvar = my_a2i(token);
		set_var_number(nvar);
		get_token(ptr, token);
		int ncls = my_a2i(token);
		set_init_cls_number(ncls);
		header_encountered = true;
		continue;
	    }
	    else {
		int lit = my_a2i(token);
		if (lit != 0)
		    literals.push_back(lit);
		else {
		    add_orig_clause_by_lits(literals);
		    literals.clear();
		}
	    }
	}
	while (get_token(ptr, token)) {
	    int lit = my_a2i(token);
	    if (lit != 0)
		literals.push_back(lit);
	    else {
		add_orig_clause_by_lits(literals);
		literals.clear();
	    }
	}
    }
    if (!literals.empty()) {
	cerr << "Trailing numbers without termination " << endl;
	exit(1);
    }
    if (clauses().size() != (unsigned)num_init_clauses()) 
	cerr << "WARNING : Clause count inconsistant with the header " << endl;
    cout << num_init_clauses() << " Clauses " << endl;
}

//  void CDatabase::construct_learned_clauses(void)
//  {
//      for (int cl_id=0; cl_id< _clauses.size(); ++cl_id) {
//  	if (_clauses[cl_id].is_built == true)
//  	    continue;

//  	CClause & cl = _clauses[cl_id];

//  	vector<int> literals;
//  	int cl1 = cl.resolvents[0];
//  	assert (_clauses[cl1].my_is_built == true);

//  	for (unsigned i=0; i< _clauses[cl1].my_literals.size(); ++i) {
//  	    int lit = _clauses[cl1].my_literals[i];
//  	    int vid = (lit>>0x1);
//  	    int sign = (lit&0x1);
//  	    assert (_variables[vid].in_clause_phase == UNKNOWN);
//  	    _variables[vid].in_clause_phase = sign;
//  	    literals.push_back(lit);
//  	}

//  	for (unsigned i=1; i< cl.resolvents.size(); ++i) {
//  	    int distance = 0;
//  	    int cl1 = cl.resolvents[i];
//  	    assert (_clauses[cl1].my_is_built == true);
//  	    for (unsigned j=0; j< _clauses[cl1].my_literals.size(); ++j) {
//  		int lit = _clauses[cl1].my_literals[j];
//  		int vid = (lit>>0x1);
//  		int sign = (lit&0x1);
//  		if (_variables[vid].in_clause_phase == UNKNOWN) {
//  		    _variables[vid].in_clause_phase = sign;
//  		    literals.push_back(lit);
//  		}
//  		else if (_variables[vid].in_clause_phase != sign) {
//  		    //distance 1 literal
//  		    ++distance;
//  		    _variables[vid].in_clause_phase = UNKNOWN;
//  		}
//  	    }
//  	    if (distance != 1) {
//  		cerr << "Resolve between two clauses with distance larger than 1" << endl;
//  		cerr << "The resulting clause is " << cl_id << endl;
//  		cerr << "Starting clause is " << cl.resolvents[0] << endl;