?? g_lll_fp.c
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#include <NTL/LLL.h>#include <NTL/fileio.h>#include <NTL/vec_double.h>#include <NTL/new.h>NTL_START_IMPLstatic 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); } }}#define TR_BND (NTL_FDOUBLE_PRECISION/2.0)// Just to be safe!!static double max_abs(double *v, long n){ long i; double res, t; res = 0; for (i = 1; i <= n; i++) { t = fabs(v[i]); if (t > res) res = t; } return res;}static void RowTransformStart(double *a, long *in_a, long& in_float, long n){ long i; long inf = 1; for (i = 1; i <= n; i++) { in_a[i] = (a[i] < TR_BND && a[i] > -TR_BND); inf = inf & in_a[i]; } in_float = inf;}static void RowTransformFinish(vec_ZZ& A, double *a, long *in_a){ long n = A.length(); long i; for (i = 1; i <= n; i++) { if (in_a[i]) { conv(A(i), a[i]); } else { conv(a[i], A(i)); } }}static void RowTransform(vec_ZZ& A, vec_ZZ& B, const ZZ& MU1, double mu, double *a, double *b, long *in_a, double& max_a, double max_b, long& in_float)// x = x - y*MU{ static ZZ T, MU; long k; long n = A.length(); long i; if (in_float) { max_a += fabs(mu)*max_b; if (max_a >= TR_BND) { in_float = 0; } } if (in_float) { if (mu == 1) { for (i = 1; i <= n; i++) a[i] -= b[i]; return; } if (mu == -1) { for (i = 1; i <= n; i++) a[i] += b[i]; return; } if (mu == 0) return; for (i = 1; i <= n; i++) a[i] -= mu*b[i]; return; } MU = MU1; if (MU == 1) { for (i = 1; i <= n; i++) { if (in_a[i] && a[i] < TR_BND && a[i] > -TR_BND && b[i] < TR_BND && b[i] > -TR_BND) { a[i] -= b[i]; } else { if (in_a[i]) { conv(A(i), a[i]); in_a[i] = 0; } sub(A(i), A(i), B(i)); } } return; } if (MU == -1) { for (i = 1; i <= n; i++) { if (in_a[i] && a[i] < TR_BND && a[i] > -TR_BND && b[i] < TR_BND && b[i] > -TR_BND) { a[i] += b[i]; } else { if (in_a[i]) { conv(A(i), a[i]); in_a[i] = 0; } add(A(i), A(i), B(i)); } } return; } if (MU == 0) return; double b_bnd = fabs(TR_BND/mu) - 1; if (b_bnd < 0) b_bnd = 0; if (NumTwos(MU) >= NTL_ZZ_NBITS) k = MakeOdd(MU); else k = 0; if (MU.WideSinglePrecision()) { long mu1; conv(mu1, MU); if (k > 0) { for (i = 1; i <= n; i++) { if (in_a[i]) { conv(A(i), a[i]); in_a[i] = 0; } mul(T, B(i), mu1); LeftShift(T, T, k); sub(A(i), A(i), T); } } else { for (i = 1; i <= n; i++) { if (in_a[i] && a[i] < TR_BND && a[i] > -TR_BND && b[i] < b_bnd && b[i] > -b_bnd) { a[i] -= b[i]*mu; } else { if (in_a[i]) { conv(A(i), a[i]); in_a[i] = 0; } mul(T, B(i), mu1); sub(A(i), A(i), T); } } } } else { for (i = 1; i <= n; i++) { if (in_a[i]) { conv(A(i), a[i]); in_a[i] = 0; } 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); } }}class GivensCache_FP {public: GivensCache_FP(long m, long n); ~GivensCache_FP(); void flush(); void selective_flush(long l); void swap(long l); void swap(); void touch(); void incr(); long sz; double **buf; long *bl; long *bv; long bp;};GivensCache_FP::GivensCache_FP(long m, long n){ sz = min(m, n)/10; if (sz < 2) sz = 2; else if (sz > 20) sz = 20; typedef double *doubleptr; long i; buf = NTL_NEW_OP doubleptr[sz]; if (!buf) Error("out of memory"); for (i = 0; i < sz; i++) if (!(buf[i] = NTL_NEW_OP double[n+1])) Error("out of memory"); bl = NTL_NEW_OP long[sz]; if (!bl) Error("out of memory"); for (i = 0; i < sz; i++) bl[0] = 0; bv = NTL_NEW_OP long[sz]; if (!bv) Error("out of memory"); for (i = 0; i < sz; i++) bv[0] = 0; bp = 0;}GivensCache_FP::~GivensCache_FP(){ long i; for (i = 0; i < sz; i++) delete [] buf[i]; delete [] buf; delete [] bl; delete [] bv;}void GivensCache_FP::flush(){ long i; for (i = 0; i < sz; i++) bl[i] = 0;}void GivensCache_FP::selective_flush(long l){ long i; for (i = 0; i < sz; i++) if (bl[i] && bv[i] >= l) bl[i] = 0;}void GivensCache_FP::swap(long l){ long k = bl[bp]; long i; i = 0; while (i < sz && bl[i] != l) i++; if (i < sz) { bl[bp] = l; bl[i] = k; } else bl[bp] = l; selective_flush(l);}void GivensCache_FP::swap(){ swap(bl[bp] - 1);}void GivensCache_FP::touch(){ long k = bl[bp]; bl[bp] = 0; selective_flush(k);}void GivensCache_FP::incr(){ long k = bl[bp]; long k1 = k+1; long i; i = 0; while (i < sz && bl[i] != k1) i++; if (i < sz) { bp = i; return; } i = 0; while (i < sz && bl[i] != 0) i++; if (i < sz) { bp = i; return; } long max_val = 0; long max_index = 0; for (i = 0; i < sz; i++) { long t = labs(bl[i]-k1); if (t > max_val) { max_val = t; max_index = i; } } bp = max_index; bl[max_index] = 0;}staticvoid GivensComputeGS(double **B1, double **mu, double **aux, long k, long n, GivensCache_FP& cache){ long i, j; double c, s, a, b, t; double *p = mu[k]; double *pp = cache.buf[cache.bp]; if (!cache.bl[cache.bp]) { for (j = 1; j <= n; j++) pp[j] = B1[k][j]; long backoff; backoff = k/4; if (backoff < 2) backoff = 2; else if (backoff > cache.sz + 2) backoff = cache.sz + 2; long ub = k-(backoff-1); for (i = 1; i < ub; i++) { double *cptr = mu[i]; double *sptr = aux[i]; for (j = n; j > i; j--) { c = cptr[j]; s = sptr[j]; a = c*pp[j-1] - s*pp[j]; b = s*pp[j-1] + c*pp[j]; pp[j-1] = a; pp[j] = b; } pp[i] = pp[i]/mu[i][i]; } cache.bl[cache.bp] = k; cache.bv[cache.bp] = k-backoff; } for (j = 1; j <= n; j++) p[j] = pp[j]; for (i = max(cache.bv[cache.bp]+1, 1); i < k; i++) { double *cptr = mu[i]; double *sptr = aux[i]; for (j = n; j > i; j--) { c = cptr[j]; s = sptr[j]; a = c*p[j-1] - s*p[j]; b = s*p[j-1] + c*p[j]; p[j-1] = a; p[j] = b; } p[i] = p[i]/mu[i][i]; } for (j = n; j > k; j--) { a = p[j-1]; b = p[j]; if (b == 0) { c = 1; s = 0; } else if (fabs(b) > fabs(a)) { t = -a/b; s = 1/sqrt(1 + t*t); c = s*t; } else { t = -b/a; c = 1/sqrt(1 + t*t); s = c*t; } p[j-1] = c*a - s*b; p[j] = c; aux[k][j] = s; } if (k > n+1) Error("G_LLL_FP: internal error"); if (k > n) p[k] = 0;
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