예제 #1
0
파일: LLL_XD.c 프로젝트: axelexic/NTL
static
long ll_LLL_XD(mat_ZZ& B, mat_ZZ* U, xdouble delta, long deep, 
           LLLCheckFct check, xdouble **B1, xdouble **mu, 
           xdouble *b, xdouble *c,
           long m, long init_k, long &quit)
{
   long n = B.NumCols();

   long i, j, k, Fc1;
   ZZ MU;
   xdouble mu1;

   xdouble t1;
   ZZ T1;
   xdouble *tp;


   NTL_THREAD_LOCAL static xdouble bound = to_xdouble(0);


   if (bound == 0) {
      // we tolerate a 15% loss of precision in computing
      // inner products in ComputeGS.

      bound = 1;
      for (i = 2*long(0.15*NTL_DOUBLE_PRECISION); i > 0; i--) {
         bound = bound * 2;
      }
   }


   xdouble half = to_xdouble(0.5);
   xdouble half_plus_fudge = 0.5 + red_fudge;

   quit = 0;
   k = init_k;

   vec_long st_mem;
   st_mem.SetLength(m+2);
   long *st = st_mem.elts();

   for (i = 1; i < k; i++)
      st[i] = i;

   for (i = k; i <= m+1; i++)
      st[i] = 1;

   UniqueArray<xdouble> buf_store;
   buf_store.SetLength(m+1);
   xdouble *buf = buf_store.get();

   long rst;
   long counter;

   long trigger_index;
   long small_trigger;
   long cnt;

   long max_k = 0;

   double tt;


   while (k <= m) {

      if (k > max_k) {
         max_k = k;
      }

      if (verbose) {
         tt = GetTime();

         if (tt > LastTime + LLLStatusInterval)
            LLLStatus(max_k, tt, m, B);
      }


      if (st[k] == k)
         rst = 1;
      else
         rst = k;

      if (st[k] < st[k+1]) st[k+1] = st[k];
      ComputeGS(B, B1, mu, b, c, k, bound, st[k], buf);
      st[k] = k;

      counter = 0;
      trigger_index = k;
      small_trigger = 0;
      cnt = 0;

      do {
         // size reduction

         counter++;
         if (counter > 10000) {
            cerr << "LLL_XD: warning--possible infinite loop\n";
            counter = 0;
         }


         Fc1 = 0;
   
         for (j = rst-1; j >= 1; j--) {
            t1 = fabs(mu[k][j]);
            if (t1 > half_plus_fudge) {

               if (!Fc1) {
                  if (j > trigger_index ||
                      (j == trigger_index && small_trigger)) {

                     cnt++;

                     if (cnt > 10) {
                        inc_red_fudge();
                        half_plus_fudge = 0.5 + red_fudge;
                        cnt = 0;
                     }
                  }

                  trigger_index = j;
                  small_trigger = (t1 < 4);
               }


               Fc1 = 1;
   
               mu1 = mu[k][j];
               if (mu1 >= 0)
                  mu1 = ceil(mu1-half);
               else
                  mu1 = floor(mu1+half);
   
   
               xdouble *mu_k = mu[k];
               xdouble *mu_j = mu[j];
  
               if (mu1 == 1) {
                  for (i = 1; i <= j-1; i++)
                     mu_k[i] -= mu_j[i];
               }
               else if (mu1 == -1) {
                  for (i = 1; i <= j-1; i++)
                     mu_k[i] += mu_j[i];
               }
               else {
                  for (i = 1; i <= j-1; i++)
                     MulSub(mu_k[i], mu_k[i], mu1, mu_j[i]);
               }
  
               mu_k[j] -= mu1;

               conv(MU, mu1);

               // cout << j << " " << MU << "\n";
   
               RowTransform(B(k), B(j), MU);
               if (U) RowTransform((*U)(k), (*U)(j), MU);
            }
         }

         if (Fc1) {
            for (i = 1; i <= n; i++)
               conv(B1[k][i], B(k, i));
   
            b[k] = InnerProduct(B1[k], B1[k], n);
            ComputeGS(B, B1, mu, b, c, k, bound, 1, buf);
         }
      } while (Fc1);

      if (check && (*check)(B(k))) 
         quit = 1;

      if (b[k] == 0) {
         for (i = k; i < m; i++) {
            // swap i, i+1
            swap(B(i), B(i+1));
            tp = B1[i]; B1[i] = B1[i+1]; B1[i+1] = tp;
            t1 = b[i]; b[i] = b[i+1]; b[i+1] = t1;
            if (U) swap((*U)(i), (*U)(i+1));
         }

         for (i = k; i <= m+1; i++) st[i] = 1;

         m--;
         if (quit) break;
         continue;
      }

      if (quit) break;

      if (deep > 0) {
         // deep insertions
   
         xdouble cc = b[k];
         long l = 1;
         while (l <= k-1 && delta*c[l] <= cc) {
            cc = cc - mu[k][l]*mu[k][l]*c[l];
            l++;
         }
   
         if (l <= k-1 && (l <= deep || k-l <= deep)) {
            // deep insertion at position l
   
            for (i = k; i > l; i--) {
               // swap rows i, i-1
               swap(B(i), B(i-1));
               tp = B1[i]; B1[i] = B1[i-1]; B1[i-1] = tp;
               tp = mu[i]; mu[i] = mu[i-1]; mu[i-1] = tp;
               t1 = b[i]; b[i] = b[i-1]; b[i-1] = t1;
               if (U) swap((*U)(i), (*U)(i-1));
            }
   
            k = l;
            continue;
         }
      } // end deep insertions

      // test LLL reduction condition

      if (k > 1 && delta*c[k-1] > c[k] + mu[k][k-1]*mu[k][k-1]*c[k-1]) {
         // swap rows k, k-1
         swap(B(k), B(k-1));
         tp = B1[k]; B1[k] = B1[k-1]; B1[k-1] = tp;
         tp = mu[k]; mu[k] = mu[k-1]; mu[k-1] = tp;
         t1 = b[k]; b[k] = b[k-1]; b[k-1] = t1;
         if (U) swap((*U)(k), (*U)(k-1));

         k--;
         NumSwaps++;

         // cout << "- " << k << "\n";
      }
      else {
         k++;
         // cout << "+ " << k << "\n";
      }
   }

   if (verbose) {
      LLLStatus(m+1, GetTime(), m, B);
   }


   return m;
}
예제 #2
0
static
long ll_G_LLL_XD(mat_ZZ& B, mat_ZZ* U, xdouble delta, long deep, 
           LLLCheckFct check, xdouble **B1, xdouble **mu, 
           xdouble **aux,
           long m, long init_k, long &quit, GivensCache_XD& cache)
{
   long n = B.NumCols();

   long i, j, k, Fc1;
   ZZ MU;
   xdouble mu1;

   xdouble t1;
   ZZ T1;
   xdouble *tp;


   xdouble half = to_xdouble(0.5);
   xdouble half_plus_fudge = 0.5 + red_fudge;

   quit = 0;
   k = init_k;

   long counter;

   long trigger_index;
   long small_trigger;
   long cnt;

   long max_k = 0;

   double tt;

   cache.flush();

   while (k <= m) {

      if (k > max_k) {
         max_k = k;
      }

      if (verbose) {
         tt = GetTime();

         if (tt > LastTime + LLLStatusInterval)
            G_LLLStatus(max_k, tt, m, B);
      }


      GivensComputeGS(B1, mu, aux, k, n, cache);

      counter = 0;
      trigger_index = k;
      small_trigger = 0;
      cnt = 0;

      do {
         // size reduction

         counter++;
         if (counter > 10000) {
            cerr << "G_LLL_XD: warning--possible infinite loop\n";
            counter = 0;
         }


         Fc1 = 0;
   
         for (j = k-1; j >= 1; j--) {
            t1 = fabs(mu[k][j]);
            if (t1 > half_plus_fudge) {

               if (!Fc1) {
                  if (j > trigger_index ||
                      (j == trigger_index && small_trigger)) {

                     cnt++;

                     if (cnt > 10) {
                        inc_red_fudge();
                        half_plus_fudge = 0.5 + red_fudge;
                        cnt = 0;
                     }
                  }

                  trigger_index = j;
                  small_trigger = (t1 < 4);
               }


               Fc1 = 1;
   
               mu1 = mu[k][j];
               if (mu1 >= 0)
                  mu1 = ceil(mu1-half);
               else
                  mu1 = floor(mu1+half);
   
   
               xdouble *mu_k = mu[k];
               xdouble *mu_j = mu[j];
  
               if (mu1 == 1) {
                  for (i = 1; i <= j-1; i++)
                     mu_k[i] -= mu_j[i];
               }
               else if (mu1 == -1) {
                  for (i = 1; i <= j-1; i++)
                     mu_k[i] += mu_j[i];
               }
               else {
                  for (i = 1; i <= j-1; i++)
                     MulSub(mu_k[i], mu_k[i], mu1, mu_j[i]);
               }
  
               mu_k[j] -= mu1;

               conv(MU, mu1);

               // cout << j << " " << MU << "\n";
   
               RowTransform(B(k), B(j), MU);
               if (U) RowTransform((*U)(k), (*U)(j), MU);
            }
         }

         if (Fc1) {
            for (i = 1; i <= n; i++)
               conv(B1[k][i], B(k, i));
            cache.touch();
            GivensComputeGS(B1, mu, aux, k, n, cache);
         }
      } while (Fc1);

      if (check && (*check)(B(k))) 
         quit = 1;

      if (IsZero(B(k))) {
         for (i = k; i < m; i++) {
            // swap i, i+1
            swap(B(i), B(i+1));
            tp = B1[i]; B1[i] = B1[i+1]; B1[i+1] = tp;
            if (U) swap((*U)(i), (*U)(i+1));
         }

         cache.flush();

         m--;
         if (quit) break;
         continue;
      }

      if (quit) break;

      if (deep > 0) {
         // deep insertions
   
         Error("sorry...deep insertions not implemented");
      } // end deep insertions

      // test G_LLL reduction condition

      if (k > 1 && 
         (delta - mu[k][k-1]*mu[k][k-1])*(mu[k-1][k-1])*(mu[k-1][k-1]) >
         (mu[k][k])*(mu[k][k])) {

         // swap rows k, k-1
         swap(B(k), B(k-1));
         tp = B1[k]; B1[k] = B1[k-1]; B1[k-1] = tp;
         if (U) swap((*U)(k), (*U)(k-1));

         cache.swap();

         k--;
         NumSwaps++;

         // cout << "- " << k << "\n";
      }
      else {
         cache.incr();
         k++;
         // cout << "+ " << k << "\n";
      }
   }

   if (verbose) {
      G_LLLStatus(m+1, GetTime(), m, B);
   }


   return m;
}