Var Solver::newVar(bool sign, bool dvar),默认sign为true，dvar为true

Var Solver::newVar(bool sign, bool dvar) {
    int v = nVars();
    watches.init(mkLit(v, false));
    watches.init(mkLit(v, true));
    watchesBin.init(mkLit(v, false));
    watchesBin.init(mkLit(v, true));

    assigns.push(l_Undef);

    vardata.push(mkVarData(CRef_Undef, 0));

    //activity .push(0);

    activity.push(rnd_init_act ? drand(random_seed) * 0.00001 : 0);

    seen.push(0);

    permDiff.push(0);

    polarity.push(sign);

    decision.push();
    trail.capacity(v + 1);

    setDecisionVar(v, dvar);//确定变量是否将要进行选择
    return v;
}

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1、watches是OccLists<Lit,vec<Watcher>,WatcherDeleted>类型

    template<class Idx, class Vec, class Deleted>
    class OccLists {
        vec <Vec> occs;
        vec<char> dirty;
        vec <Idx> dirties;
        Deleted deleted;

        void init(const Idx &idx) {
            occs.growTo(toInt(idx) + 1);//设置occs长度+1
            dirty.growTo(toInt(idx) + 1, 0);//设置dirty长度+1，并且元素初始化为0
        }

2、watchesBin同watches

3、assign是vec<lbool>类型，初始赋值为l_Undef（uint8_t  2）

4、vardata是vec<VarData>

 struct VarData { CRef reason; int level; };

static inline VarData mkVarData(CRef cr, int l){ VarData d = {cr, l}; return d; }

初始化对reason赋值CRef_Undef（UINT32_MAX）,level赋值为0

5、activity是vec<double>类型，初始赋值为 rnd_init_act ? drand(random_seed) * 0.00001 : 0。其中rnd_init_act为设置参数

6、seen是vec<char>类型，初始赋值为0

7、permDiff是vec<unsigned int>类型，初始为0

8、plarity是vec<char>类型,初始为“\001”

9、decsion是vec<char>类型，初始为“”

10、trail是vec<Lit>类型,只增大其cap

---

inline int      Solver::nVars         ()      const   { return vardata.size(); }

inline void     Solver::setDecisionVar(Var v, bool b)
{
    if      ( b && !decision[v]) dec_vars++;
    else if (!b &&  decision[v]) dec_vars--;

    decision[v] = b;
    insertVarOrder(v);
}

inline void Solver::insertVarOrder(Var x) {
    if (!order_heap.inHeap(x) && decision[x]) order_heap.insert(x); }