C++ vec_ZZ_pE::length方法代码示例

void sub(vec_ZZ_pE& x, const vec_ZZ_pE& a, const vec_ZZ_pE& b)
{
   long n = a.length();
   if (b.length() != n) LogicError("vector sub: dimension mismatch");

   x.SetLength(n);
   long i;
   for (i = 0; i < n; i++)
      sub(x[i], a[i], b[i]);
}

void add(vec_ZZ_pE& x, const vec_ZZ_pE& a, const vec_ZZ_pE& b)
{
   long n = a.length();
   if (b.length() != n) Error("vector add: dimension mismatch");

   x.SetLength(n);
   long i;
   for (i = 0; i < n; i++)
      add(x[i], a[i], b[i]);
}

void InnerProduct(ZZ_pE& x, const vec_ZZ_pE& a, const vec_ZZ_pE& b)
{
   long n = min(a.length(), b.length());
   long i;
   ZZ_pX accum, t;

   clear(accum);
   for (i = 0; i < n; i++) {
      mul(t, rep(a[i]), rep(b[i]));
      add(accum, accum, t);
   }

   conv(x, accum);
}

void clear(vec_ZZ_pE& x)
{
   long n = x.length();
   long i;
   for (i = 0; i < n; i++)
      clear(x[i]);
}

void negate(vec_ZZ_pE& x, const vec_ZZ_pE& a)
{
   long n = a.length();

   x.SetLength(n);
   long i;
   for (i = 0; i < n; i++)
      negate(x[i], a[i]);
}

void mul(vec_ZZ_pE& x, const vec_ZZ_pE& a, const ZZ_pE& b_in)
{
   ZZ_pE b = b_in;
   long n = a.length();
   x.SetLength(n);
   long i;
   for (i = 0; i < n; i++)
      mul(x[i], a[i], b);
}

void InnerProduct(ZZ_pE& x, const vec_ZZ_pE& a, const vec_ZZ_pE& b,
                  long offset)
{
   if (offset < 0) LogicError("InnerProduct: negative offset");
   if (NTL_OVERFLOW(offset, 1, 0)) ResourceError("InnerProduct: offset too big");

   long n = min(a.length(), b.length()+offset);
   long i;
   ZZ_pX accum, t;

   clear(accum);
   for (i = offset; i < n; i++) {
      mul(t, rep(a[i]), rep(b[i-offset]));
      add(accum, accum, t);
   }

   conv(x, accum);
}

void FindFactors(vec_ZZ_pEX& factors, const ZZ_pEX& f, const ZZ_pEX& g,
                 const vec_ZZ_pE& roots)
{
   long r = roots.length();

   factors.SetMaxLength(r);
   factors.SetLength(0);

   RecFindFactors(factors, f, g, roots, 0, r-1);
}

long IsZero(const vec_ZZ_pE& a)
{
   long n = a.length();
   long i;

   for (i = 0; i < n; i++)
      if (!IsZero(a[i]))
         return 0;

   return 1;
}

void IterFindFactors(vec_ZZ_pEX& factors, const ZZ_pEX& f,
                     const ZZ_pEX& g, const vec_ZZ_pE& roots)
{
   long r = roots.length();
   long i;
   ZZ_pEX h;

   factors.SetLength(r);

   for (i = 0; i < r; i++) {
      sub(h, g, roots[i]);
      GCD(factors[i], f, h);
   }
}

void VectorCopy(vec_ZZ_pE& x, const vec_ZZ_pE& a, long n)
{
   if (n < 0) LogicError("VectorCopy: negative length");
   if (NTL_OVERFLOW(n, 1, 0)) ResourceError("overflow in VectorCopy");

   long m = min(n, a.length());

   x.SetLength(n);
  
   long i;

   for (i = 0; i < m; i++)
      x[i] = a[i];

   for (i = m; i < n; i++)
      clear(x[i]);
}

static
void RecFindRoots(vec_ZZ_pE& x, const ZZ_pEX& f)
{
   if (deg(f) == 0) return;

   if (deg(f) == 1) {
      long k = x.length();
      x.SetLength(k+1);
      negate(x[k], ConstTerm(f));
      return;
   }
      
   ZZ_pEX h;

   ZZ_pEX r;

   
   {
      ZZ_pEXModulus F;
      build(F, f);

      do {
         random(r, deg(F));
         if (IsOdd(ZZ_pE::cardinality())) {
            PowerMod(h, r, RightShift(ZZ_pE::cardinality(), 1), F);
            sub(h, h, 1);
         }
         else {
            AbsTraceMap(h, r, F);
         }
         GCD(h, h, f);
      } while (deg(h) <= 0 || deg(h) == deg(f));
   }

   RecFindRoots(x, h);
   div(h, f, h); 
   RecFindRoots(x, h);
}

static
void mul_aux(vec_ZZ_pE& x, const mat_ZZ_pE& A, const vec_ZZ_pE& b)  
{  
   long n = A.NumRows();  
   long l = A.NumCols();  
  
   if (l != b.length())  
      Error("matrix mul: dimension mismatch");  
  
   x.SetLength(n);  
  
   long i, k;  
   ZZ_pX acc, tmp;  
  
   for (i = 1; i <= n; i++) {  
      clear(acc);  
      for (k = 1; k <= l; k++) {  
         mul(tmp, rep(A(i,k)), rep(b(k)));  
         add(acc, acc, tmp);  
      }  
      conv(x(i), acc);  
   }  
}  

void solve(ZZ_pE& d, vec_ZZ_pE& X, 
           const mat_ZZ_pE& A, const vec_ZZ_pE& b)

{
   long n = A.NumRows();
   if (A.NumCols() != n)
      Error("solve: nonsquare matrix");

   if (b.length() != n)
      Error("solve: dimension mismatch");

   if (n == 0) {
      set(d);
      X.SetLength(0);
      return;
   }

   long i, j, k, pos;
   ZZ_pX t1, t2;
   ZZ_pX *x, *y;

   const ZZ_pXModulus& p = ZZ_pE::modulus();

   vec_ZZ_pX *M = NTL_NEW_OP vec_ZZ_pX[n];

   for (i = 0; i < n; i++) {
      M[i].SetLength(n+1);
      for (j = 0; j < n; j++) {
         M[i][j].rep.SetMaxLength(2*deg(p)-1);
         M[i][j] = rep(A[j][i]);
      }
      M[i][n].rep.SetMaxLength(2*deg(p)-1);
      M[i][n] = rep(b[i]);
   }

   ZZ_pX det;
   set(det);

   for (k = 0; k < n; k++) {
      pos = -1;
      for (i = k; i < n; i++) {
         rem(t1, M[i][k], p);
         M[i][k] = t1;
         if (pos == -1 && !IsZero(t1)) {
            pos = i;
         }
      }

      if (pos != -1) {
         if (k != pos) {
            swap(M[pos], M[k]);
            negate(det, det);
         }

         MulMod(det, det, M[k][k], p);

         // make M[k, k] == -1 mod p, and make row k reduced

         InvMod(t1, M[k][k], p);
         negate(t1, t1);
         for (j = k+1; j <= n; j++) {
            rem(t2, M[k][j], p);
            MulMod(M[k][j], t2, t1, p);
         }

         for (i = k+1; i < n; i++) {
            // M[i] = M[i] + M[k]*M[i,k]

            t1 = M[i][k];   // this is already reduced

            x = M[i].elts() + (k+1);
            y = M[k].elts() + (k+1);

            for (j = k+1; j <= n; j++, x++, y++) {
               // *x = *x + (*y)*t1

               mul(t2, *y, t1);
               add(*x, *x, t2);
            }
         }
      }
      else {
         clear(d);
         goto done;
      }
   }

   X.SetLength(n);
   for (i = n-1; i >= 0; i--) {
      clear(t1);
      for (j = i+1; j < n; j++) {
         mul(t2, rep(X[j]), M[i][j]);
         add(t1, t1, t2);
      }
      sub(t1, t1, M[i][n]);
      conv(X[i], t1);
   }

   conv(d, det);

//.........这里部分代码省略.........