?? lll_xd.c
字號:
#include <NTL/LLL.h>#include <NTL/fileio.h>#include <NTL/vec_xdouble.h>#include <NTL/vec_double.h>#include <NTL/new.h>NTL_START_IMPLstatic xdouble InnerProduct(xdouble *a, xdouble *b, long n){ xdouble s; long i; s = 0; for (i = 1; i <= n; i++) MulAdd(s, s, a[i], b[i]); return s;}static void RowTransform(vec_ZZ& A, vec_ZZ& B, const ZZ& MU1)// x = x - y*MU{ static ZZ T, MU; long k; long n = A.length(); long i; MU = MU1; if (MU == 1) { for (i = 1; i <= n; i++) sub(A(i), A(i), B(i)); return; } if (MU == -1) { for (i = 1; i <= n; i++) add(A(i), A(i), B(i)); return; } if (MU == 0) return; if (NumTwos(MU) >= NTL_ZZ_NBITS) k = MakeOdd(MU); else k = 0; if (MU.WideSinglePrecision()) { long mu1; conv(mu1, MU); for (i = 1; i <= n; i++) { mul(T, B(i), mu1); if (k > 0) LeftShift(T, T, k); sub(A(i), A(i), T); } } else { for (i = 1; i <= n; i++) { mul(T, B(i), MU); if (k > 0) LeftShift(T, T, k); sub(A(i), A(i), T); } }}static void RowTransform2(vec_ZZ& A, vec_ZZ& B, const ZZ& MU1)// x = x + y*MU{ static ZZ T, MU; long k; long n = A.length(); long i; MU = MU1; if (MU == 1) { for (i = 1; i <= n; i++) add(A(i), A(i), B(i)); return; } if (MU == -1) { for (i = 1; i <= n; i++) sub(A(i), A(i), B(i)); return; } if (MU == 0) return; if (NumTwos(MU) >= NTL_ZZ_NBITS) k = MakeOdd(MU); else k = 0; if (MU.WideSinglePrecision()) { long mu1; conv(mu1, MU); for (i = 1; i <= n; i++) { mul(T, B(i), mu1); if (k > 0) LeftShift(T, T, k); add(A(i), A(i), T); } } else { for (i = 1; i <= n; i++) { mul(T, B(i), MU); if (k > 0) LeftShift(T, T, k); add(A(i), A(i), T); } }}staticvoid ComputeGS(mat_ZZ& B, xdouble **B1, xdouble **mu, xdouble *b, xdouble *c, long k, xdouble bound, long st, xdouble *buf){ long n = B.NumCols(); long i, j; xdouble s, t1, y, t; ZZ T1; xdouble *mu_k = mu[k]; if (st < k) { for (i = 1; i < st; i++) buf[i] = mu_k[i]*c[i]; } for (j = st; j <= k-1; j++) { if (b[k]*b[j] < NTL_FDOUBLE_PRECISION*NTL_FDOUBLE_PRECISION) { double z = 0; xdouble *B1_k = B1[k]; xdouble *B1_j = B1[j]; for (i = 1; i <= n; i++) z += B1_k[i].x * B1_j[i].x; s = z; } else { s = InnerProduct(B1[k], B1[j], n); if (s*s <= b[k]*b[j]/bound) { InnerProduct(T1, B(k), B(j)); conv(s, T1); } } xdouble *mu_j = mu[j]; t1 = 0; for (i = 1; i <= j-1; i++) MulAdd(t1, t1, mu_j[i], buf[i]); mu_k[j] = (buf[j] = (s - t1))/c[j]; } s = 0; for (j = 1; j <= k-1; j++) MulAdd(s, s, mu_k[j], buf[j]); c[k] = b[k] - s;}static xdouble red_fudge = to_xdouble(0);static long log_red = 0;static void init_red_fudge(){ long i; log_red = long(0.50*NTL_DOUBLE_PRECISION); red_fudge = 1; for (i = log_red; i > 0; i--) red_fudge = red_fudge*0.5;}static void inc_red_fudge(){ red_fudge = red_fudge * 2; log_red--; cerr << "LLL_XD: warning--relaxing reduction (" << log_red << ")\n"; if (log_red < 4) Error("LLL_XD: can not continue...sorry");}static long verbose = 0;static unsigned long NumSwaps = 0;static double StartTime = 0;static double LastTime = 0;static void LLLStatus(long max_k, double t, long m, const mat_ZZ& B){ cerr << "---- LLL_XD status ----\n"; cerr << "elapsed time: "; PrintTime(cerr, t-StartTime); cerr << ", stage: " << max_k; cerr << ", rank: " << m; cerr << ", swaps: " << NumSwaps << "\n"; ZZ t1; long i; double prodlen = 0; for (i = 1; i <= m; i++) { InnerProduct(t1, B(i), B(i)); if (!IsZero(t1)) prodlen += log(t1); } cerr << "log of prod of lengths: " << prodlen/(2.0*log(2.0)) << "\n"; if (LLLDumpFile) { cerr << "dumping to " << LLLDumpFile << "..."; ofstream f; OpenWrite(f, LLLDumpFile); f << "["; for (i = 1; i <= m; i++) { f << B(i) << "\n"; } f << "]\n"; f.close(); cerr << "\n"; } LastTime = t; }staticlong 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; 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; xdouble *buf; buf = NTL_NEW_OP xdouble [m+1]; if (!buf) Error("out of memory in lll_LLL_XD"); 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); } delete [] buf; return m;}staticlong LLL_XD(mat_ZZ& B, mat_ZZ* U, xdouble delta, long deep, LLLCheckFct check){ long m = B.NumRows(); long n = B.NumCols(); long i, j; long new_m, dep, quit; xdouble s; ZZ MU; xdouble mu1; xdouble t1; ZZ T1; init_red_fudge(); if (U) ident(*U, m); xdouble **B1; // approximates B typedef xdouble *xdoubleptr; B1 = NTL_NEW_OP xdoubleptr[m+1]; if (!B1) Error("LLL_XD: out of memory"); for (i = 1; i <= m; i++) { B1[i] = NTL_NEW_OP xdouble[n+1]; if (!B1[i]) Error("LLL_XD: out of memory"); } xdouble **mu; mu = NTL_NEW_OP xdoubleptr[m+1]; if (!mu) Error("LLL_XD: out of memory"); for (i = 1; i <= m; i++) { mu[i] = NTL_NEW_OP xdouble[m+1]; if (!mu[i]) Error("LLL_XD: out of memory"); } xdouble *c; // squared lengths of Gramm-Schmidt basis vectors c = NTL_NEW_OP xdouble[m+1]; if (!c) Error("LLL_XD: out of memory"); xdouble *b; // squared lengths of basis vectors b = NTL_NEW_OP xdouble[m+1]; if (!b) Error("LLL_XD: out of memory"); for (i = 1; i <=m; i++) for (j = 1; j <= n; j++) conv(B1[i][j], B(i, j)); for (i = 1; i <= m; i++) { b[i] = InnerProduct(B1[i], B1[i], n); } new_m = ll_LLL_XD(B, U, delta, deep, check, B1, mu, b, c, m, 1, quit); dep = m - new_m; m = new_m; if (dep > 0) { // for consistency, we move all of the zero rows to the front for (i = 0; i < m; i++) { swap(B(m+dep-i), B(m-i)); if (U) swap((*U)(m+dep-i), (*U)(m-i)); } } // clean-up for (i = 1; i <= m; i++) { delete [] B1[i]; } delete [] B1; for (i = 1; i <= m; i++) { delete [] mu[i]; } delete [] mu; delete [] c; delete [] b; return m;} long LLL_XD(mat_ZZ& B, double delta, long deep, LLLCheckFct check, long verb){ verbose = verb; NumSwaps = 0; if (verbose) { StartTime = GetTime(); LastTime = StartTime; } if (delta < 0.50 || delta >= 1) Error("LLL_XD: bad delta"); if (deep < 0) Error("LLL_XD: bad deep"); return LLL_XD(B, 0, to_xdouble(delta), deep, check);}long LLL_XD(mat_ZZ& B, mat_ZZ& U, double delta, long deep, LLLCheckFct check, long verb){ verbose = verb; NumSwaps = 0; if (verbose) { StartTime = GetTime(); LastTime = StartTime; }
?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -