use mag methods for hypgeom bounding code; add arb_hypgeom_sum methods

This commit is contained in:
Fredrik Johansson 2014-06-12 20:23:36 +02:00
parent 1fa4420ee1
commit 81009e0a30
9 changed files with 439 additions and 132 deletions

View file

@ -49,29 +49,6 @@ acb_get_mag_lower(mag_t z, const acb_t x)
arf_clear(t);
}
void
mag_mul_ui(mag_t z, const mag_t x, ulong y)
{
arf_t t;
arf_init(t);
arf_set_mag(t, x);
arf_mul_ui(t, t, y, MAG_BITS, ARF_RND_UP);
arf_get_mag(z, t);
arf_clear(t);
}
void
mag_div_ui(mag_t z, const mag_t x, ulong y)
{
arf_t t;
arf_init(t);
arf_set_mag(t, x);
arf_div_ui(t, t, y, MAG_BITS, ARF_RND_UP);
arf_get_mag(z, t);
arf_clear(t);
}
/* tuning factor */
#define GAMMA_STIRLING_BETA 0.27

View file

@ -27,6 +27,8 @@
#define HYPGEOM_H
#include "fmprb.h"
#include "arb.h"
#include "mag.h"
#include "fmpz_poly.h"
#ifdef __cplusplus
@ -46,7 +48,7 @@ typedef struct
long boundC;
long boundD;
long boundK;
fmpr_t MK;
mag_t MK;
}
hypgeom_struct;
@ -58,15 +60,19 @@ void hypgeom_clear(hypgeom_t hyp);
void hypgeom_precompute(hypgeom_t hyp);
long hypgeom_estimate_terms(const fmpr_t z, int r, long prec);
long hypgeom_estimate_terms(const mag_t z, int r, long prec);
long hypgeom_bound(fmpr_t error, int r,
long C, long D, long K, const fmpr_t TK, const fmpr_t z, long prec);
long hypgeom_bound(mag_t error, int r,
long C, long D, long K, const mag_t TK, const mag_t z, long prec);
void fmprb_hypgeom_sum(fmprb_t P, fmprb_t Q, const hypgeom_t hyp, const long n, long prec);
void fmprb_hypgeom_sum(fmprb_t P, fmprb_t Q, const hypgeom_t hyp, long n, long prec);
void fmprb_hypgeom_infsum(fmprb_t P, fmprb_t Q, hypgeom_t hyp, long target_prec, long prec);
void arb_hypgeom_sum(arb_t P, arb_t Q, const hypgeom_t hyp, long n, long prec);
void arb_hypgeom_infsum(arb_t P, arb_t Q, hypgeom_t hyp, long target_prec, long prec);
#ifdef __cplusplus
}
#endif

View file

@ -103,7 +103,8 @@ fmpr_gamma_ui_ubound(fmpr_t x, ulong n, long prec)
}
}
long hypgeom_root_bound(const fmpr_t z, int r, long prec)
long
hypgeom_root_bound(const mag_t z, int r)
{
if (r == 0)
{
@ -114,8 +115,9 @@ long hypgeom_root_bound(const fmpr_t z, int r, long prec)
fmpr_t t;
long v;
fmpr_init(t);
fmpr_root(t, z, r, prec, FMPR_RND_UP);
fmpr_add_ui(t, t, 1, prec, FMPR_RND_UP);
mag_get_fmpr(t, z);
fmpr_root(t, t, r, MAG_BITS, FMPR_RND_UP);
fmpr_add_ui(t, t, 1, MAG_BITS, FMPR_RND_UP);
v = fmpr_get_si(t, FMPR_RND_UP);
fmpr_clear(t);
return v;
@ -138,129 +140,204 @@ z^n *
(K-B)! (K-A+m)! (K-2B+m)!
*/
void
hypgeom_term_bound(fmpr_t Tn, const fmpr_t TK, long K, long A, long B, int r, const fmpr_t z, long n, long wp)
hypgeom_term_bound(mag_t Tn, const mag_t TK, long K, long A, long B, int r, const mag_t z, long n)
{
fmpr_t t, u, num, den;
mag_t t, u, num;
long m;
fmpr_init(t);
fmpr_init(u);
fmpr_init(num);
fmpr_init(den);
mag_init(t);
mag_init(u);
mag_init(num);
m = n - K;
if (m < 0)
{
printf("hypgeom term bound\n");
abort();
}
/* TK * z^n */
fmpr_pow_sloppy_ui(t, z, n, wp, FMPR_RND_UP);
fmpr_mul(num, TK, t, wp, FMPR_RND_UP);
mag_pow_ui(t, z, n);
mag_mul(num, TK, t);
/* (K+A)! (K-2B)! (K-B+m)!, upper bounding */
fmpr_gamma_ui_ubound(t, K+A+1, wp);
fmpr_mul(num, num, t, wp, FMPR_RND_UP);
fmpr_gamma_ui_ubound(t, K-2*B+1, wp);
fmpr_mul(num, num, t, wp, FMPR_RND_UP);
fmpr_gamma_ui_ubound(t, K-B+m, wp);
fmpr_mul(num, num, t, wp, FMPR_RND_UP);
/* numerator: (K+A)! (K-2B)! (K-B+m)! */
mag_fac_ui(t, K+A);
mag_mul(num, num, t);
/* (K-B)! (K-A+m)! (K-2B+m)!, lower bounding */
fmpr_gamma_ui_lbound(den, K-B+1, wp);
fmpr_gamma_ui_lbound(t, K-A+m+1, wp);
fmpr_mul(den, den, t, wp, FMPR_RND_DOWN);
fmpr_gamma_ui_lbound(t, K-2*B+m+1, wp);
fmpr_mul(den, den, t, wp, FMPR_RND_DOWN);
mag_fac_ui(t, K-2*B);
mag_mul(num, num, t);
mag_fac_ui(t, K-B+m);
mag_mul(num, num, t);
/* denominator: (K-B)! (K-A+m)! (K-2B+m)! */
mag_rfac_ui(t, K-B);
mag_mul(num, num, t);
mag_rfac_ui(t, K-A+m);
mag_mul(num, num, t);
mag_rfac_ui(t, K-2*B+m);
mag_mul(num, num, t);
/* ((K+m)! / K!)^(1-r) */
if (r == 0)
{
fmpr_gamma_ui_ubound(t, K+m+1, wp);
fmpr_mul(num, num, t, wp, FMPR_RND_UP);
fmpr_gamma_ui_lbound(t, K+1, wp);
fmpr_mul(den, den, t, wp, FMPR_RND_DOWN);
mag_fac_ui(t, K+m);
mag_mul(num, num, t);
mag_rfac_ui(t, K);
mag_mul(num, num, t);
}
else if (r != 1)
{
fmpr_gamma_ui_ubound(t, K+1, wp);
fmpr_gamma_ui_lbound(u, K+m+1, wp);
fmpr_div(t, t, u, wp, FMPR_RND_UP);
fmpr_pow_sloppy_ui(t, t, r-1, wp, FMPR_RND_UP);
fmpr_mul(num, num, t, wp, FMPR_RND_UP);
mag_fac_ui(t, K);
mag_rfac_ui(u, K+m);
mag_mul(t, t, u);
mag_pow_ui(t, t, r-1);
mag_mul(num, num, t);
}
fmpr_div(Tn, num, den, wp, FMPR_RND_UP);
mag_set(Tn, num);
fmpr_clear(t);
fmpr_clear(u);
fmpr_clear(num);
fmpr_clear(den);
mag_clear(t);
mag_clear(u);
mag_clear(num);
}
/* z = max(x-y, 0), rounding down [lower bound] */
void
mag_sub_lower(mag_t z, const mag_t x, const mag_t y)
{
if (mag_is_special(x) || mag_is_special(y))
{
if (mag_is_zero(y))
mag_set(z, x);
else if (mag_is_zero(x) || mag_is_inf(y))
mag_zero(z);
else
mag_inf(z);
}
else
{
fmpr_t t, u;
fmpr_init(t);
fmpr_init(u);
mag_get_fmpr(t, x);
mag_get_fmpr(u, y);
fmpr_sub(t, t, u, MAG_BITS, FMPR_RND_DOWN);
if (fmpr_sgn(t) <= 0)
mag_zero(z);
else /* XXX: exact? */
mag_set_fmpz_2exp_fmpz_lower(z, fmpr_manref(t), fmpr_expref(t));
fmpr_clear(t);
fmpr_clear(u);
}
}
void
mag_set_ui_2exp_si(mag_t z, ulong v, long e)
{
mag_set_ui(z, v);
mag_mul_2exp_si(z, z, e);
}
double
mag_get_d(const mag_t z)
{
long exp;
if (mag_is_zero(z))
return 0.0;
else if (mag_is_inf(z))
return D_INF;
/* XXX: overflow/underflow properly */
exp = MAG_EXP(z);
if (exp < -1000)
return ldexp(1.0, -1000);
else if (exp > 1000)
return D_INF;
else
return ldexp(MAG_MAN(z), exp - MAG_BITS);
}
long
hypgeom_bound(fmpr_t error, int r,
long A, long B, long K, const fmpr_t TK, const fmpr_t z, long prec)
hypgeom_bound(mag_t error, int r,
long A, long B, long K, const mag_t TK, const mag_t z, long tol_2exp)
{
fmpr_t Tn, t, u, one, tol, num, den;
long wp = FMPRB_RAD_PREC;
mag_t Tn, t, u, one, tol, num, den;
long n, m;
fmpr_init(Tn);
fmpr_init(t);
fmpr_init(u);
fmpr_init(one);
fmpr_init(tol);
fmpr_init(num);
fmpr_init(den);
mag_init(Tn);
mag_init(t);
mag_init(u);
mag_init(one);
mag_init(tol);
mag_init(num);
mag_init(den);
fmpr_one(one);
fmpr_set_ui_2exp_si(tol, 1UL, -prec);
mag_one(one);
mag_set_ui_2exp_si(tol, 1UL, -tol_2exp);
/* approximate number of needed terms */
n = hypgeom_estimate_terms(z, r, prec);
n = hypgeom_estimate_terms(z, r, tol_2exp);
/* required for 1 + O(1/k) part to be decreasing */
n = FLINT_MAX(n, K + 1);
/* required for z^k / (k!)^r to be decreasing */
m = hypgeom_root_bound(z, r, wp);
m = hypgeom_root_bound(z, r);
n = FLINT_MAX(n, m);
/* We now have |R(k)| <= G(k) where G(k) is monotonically decreasing,
and can bound the tail using a geometric series as soon
as soon as G(k) < 1. */
as soon as G(k) < 1. */
/* bound T(n-1) */
hypgeom_term_bound(Tn, TK, K, A, B, r, z, n-1, wp);
hypgeom_term_bound(Tn, TK, K, A, B, r, z, n-1);
while (1)
{
/* bound R(n) */
fmpr_mul_ui(num, z, n, wp, FMPR_RND_UP);
fmpr_mul_ui(num, num, n - B, wp, FMPR_RND_UP);
fmpr_set_ui(den, n - A);
fmpr_mul_ui(den, den, n - 2*B, wp, FMPR_RND_DOWN);
mag_mul_ui(num, z, n);
mag_mul_ui(num, num, n - B);
mag_set_ui_lower(den, n - A);
mag_mul_ui_lower(den, den, n - 2*B);
if (r != 0)
{
fmpr_set_ui(u, n);
fmpr_pow_sloppy_ui(u, u, r, wp, FMPR_RND_DOWN);
fmpr_mul(den, den, u, wp, FMPR_RND_DOWN);
mag_set_ui_lower(u, n);
mag_pow_ui_lower(u, u, r);
mag_mul_lower(den, den, u);
}
fmpr_div(t, num, den, wp, FMPR_RND_UP);
mag_div(t, num, den);
/* multiply bound for T(n-1) by bound for R(n) to bound T(n) */
fmpr_mul(Tn, Tn, t, wp, FMPR_RND_UP);
mag_mul(Tn, Tn, t);
/* geometric series termination check */
fmpr_sub(u, one, t, wp, FMPR_RND_DOWN);
if (fmpr_sgn(u) > 0)
{
fmpr_div(u, Tn, u, wp, FMPR_RND_UP);
/* u = max(1-t, 0), rounding down [lower bound] */
mag_sub_lower(u, one, t);
if (fmpr_cmp(u, tol) < 0)
if (!mag_is_zero(u))
{
mag_div(u, Tn, u);
if (mag_cmp(u, tol) < 0)
{
fmpr_set(error, u);
mag_set(error, u);
break;
}
}
@ -269,13 +346,14 @@ hypgeom_bound(fmpr_t error, int r,
n++;
}
fmpr_clear(Tn);
fmpr_clear(t);
fmpr_clear(u);
fmpr_clear(one);
fmpr_clear(tol);
fmpr_clear(num);
fmpr_clear(den);
mag_clear(Tn);
mag_clear(t);
mag_clear(u);
mag_clear(one);
mag_clear(tol);
mag_clear(num);
mag_clear(den);
return n;
}

View file

@ -39,13 +39,14 @@ static __inline__ double d_root(double x, int r)
return pow(x, 1. / r);
}
double mag_get_d(const mag_t z);
long
hypgeom_estimate_terms(const fmpr_t z, int r, long prec)
hypgeom_estimate_terms(const mag_t z, int r, long prec)
{
double y, t;
t = fmpr_get_d(z, FMPR_RND_UP);
t = fabs(t);
t = mag_get_d(z);
if (t == 0)
return 1;

View file

@ -32,7 +32,7 @@ hypgeom_init(hypgeom_t hyp)
fmpz_poly_init(hyp->B);
fmpz_poly_init(hyp->P);
fmpz_poly_init(hyp->Q);
fmpr_init(hyp->MK);
mag_init(hyp->MK);
hyp->have_precomputed = 0;
}
@ -43,5 +43,5 @@ hypgeom_clear(hypgeom_t hyp)
fmpz_poly_clear(hyp->B);
fmpz_poly_clear(hyp->P);
fmpz_poly_clear(hyp->Q);
fmpr_clear(hyp->MK);
mag_clear(hyp->MK);
}

View file

@ -126,17 +126,15 @@ _hypgeom_precompute(hypgeom_t hyp, const fmpz_poly_t P, const fmpz_poly_t Q)
hyp->boundD = hypgeom_root_norm(Q);
hyp->boundK = 1 + FLINT_MAX(hyp->boundC, 2 * hyp->boundD);
fmpr_one(hyp->MK);
mag_one(hyp->MK);
for (k = 1; k <= hyp->boundK; k++)
{
fmpz_poly_evaluate_si(t, P, k);
fmpz_abs(t, t);
fmpr_mul_fmpz(hyp->MK, hyp->MK, t, FMPRB_RAD_PREC, FMPR_RND_UP);
mag_mul_fmpz(hyp->MK, hyp->MK, t);
fmpz_poly_evaluate_si(t, Q, k);
fmpz_abs(t, t);
fmpr_div_fmpz(hyp->MK, hyp->MK, t, FMPRB_RAD_PREC, FMPR_RND_UP);
mag_div_fmpz(hyp->MK, hyp->MK, t);
}
fmpz_clear(t);
@ -163,12 +161,10 @@ hypgeom_precompute(hypgeom_t hyp)
fmpz_init(t);
fmpz_poly_evaluate_si(t, hyp->A, 0);
fmpz_abs(t, t);
fmpr_mul_fmpz(hyp->MK, hyp->MK, t, FMPRB_RAD_PREC, FMPR_RND_UP);
mag_mul_fmpz(hyp->MK, hyp->MK, t);
fmpz_poly_evaluate_si(t, hyp->B, 0);
fmpz_abs(t, t);
fmpr_div_fmpz(hyp->MK, hyp->MK, t, FMPRB_RAD_PREC, FMPR_RND_UP);
mag_div_fmpz(hyp->MK, hyp->MK, t);
fmpz_clear(t);
}

View file

@ -159,7 +159,7 @@ bsplit_recursive_fmprb(fmprb_t P, fmprb_t Q, fmprb_t B, fmprb_t T,
}
void
fmprb_hypgeom_sum(fmprb_t P, fmprb_t Q, const hypgeom_t hyp, const long n, long prec)
fmprb_hypgeom_sum(fmprb_t P, fmprb_t Q, const hypgeom_t hyp, long n, long prec)
{
if (n < 1)
{
@ -183,17 +183,14 @@ fmprb_hypgeom_sum(fmprb_t P, fmprb_t Q, const hypgeom_t hyp, const long n, long
void
fmprb_hypgeom_infsum(fmprb_t P, fmprb_t Q, hypgeom_t hyp, long target_prec, long prec)
{
fmpr_t err;
fmpr_t z;
mag_t err, z;
long n;
fmpr_init(err);
fmpr_init(z);
mag_init(err);
mag_init(z);
fmpr_fmpz_div_fmpz(z,
hyp->P->coeffs + hyp->P->length - 1,
hyp->Q->coeffs + hyp->Q->length - 1, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_abs(z, z);
mag_set_fmpz(z, hyp->P->coeffs + hyp->P->length - 1);
mag_div_fmpz(z, z, hyp->Q->coeffs + hyp->Q->length - 1);
if (!hyp->have_precomputed)
{
@ -214,14 +211,148 @@ fmprb_hypgeom_infsum(fmprb_t P, fmprb_t Q, hypgeom_t hyp, long target_prec, long
/* We have p/q = s + err i.e. (p + q*err)/q = s */
{
fmpr_t u;
fmpr_t u, v;
fmpr_init(u);
fmpr_init(v);
mag_get_fmpr(v, err);
fmpr_add(u, fmprb_midref(Q), fmprb_radref(Q), FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_mul(u, u, err, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_mul(u, u, v, FMPRB_RAD_PREC, FMPR_RND_UP);
fmprb_add_error_fmpr(P, u);
fmpr_clear(u);
fmpr_clear(v);
}
fmpr_clear(z);
fmpr_clear(err);
mag_clear(z);
mag_clear(err);
}
static void
bsplit_recursive_arb(arb_t P, arb_t Q, arb_t B, arb_t T,
const hypgeom_t hyp, long a, long b, int cont, long prec)
{
if (b - a < 4)
{
fmpz_t PP, QQ, BB, TT;
fmpz_init(PP);
fmpz_init(QQ);
fmpz_init(BB);
fmpz_init(TT);
bsplit_recursive_fmpz(PP, QQ, BB, TT, hyp, a, b, cont);
arb_set_fmpz(P, PP);
arb_set_fmpz(Q, QQ);
arb_set_fmpz(B, BB);
arb_set_fmpz(T, TT);
fmpz_clear(PP);
fmpz_clear(QQ);
fmpz_clear(BB);
fmpz_clear(TT);
}
else
{
long m;
arb_t P2, Q2, B2, T2;
m = (a + b) / 2;
arb_init(P2);
arb_init(Q2);
arb_init(B2);
arb_init(T2);
bsplit_recursive_arb(P, Q, B, T, hyp, a, m, 1, prec);
bsplit_recursive_arb(P2, Q2, B2, T2, hyp, m, b, 1, prec);
if (arb_is_one(B) && arb_is_one(B2))
{
arb_mul(T, T, Q2, prec);
arb_addmul(T, P, T2, prec);
}
else
{
arb_mul(T, T, B2, prec);
arb_mul(T, T, Q2, prec);
arb_mul(T2, T2, B, prec);
arb_addmul(T, P, T2, prec);
}
arb_mul(B, B, B2, prec);
arb_mul(Q, Q, Q2, prec);
if (cont)
arb_mul(P, P, P2, prec);
arb_clear(P2);
arb_clear(Q2);
arb_clear(B2);
arb_clear(T2);
}
}
void
arb_hypgeom_sum(arb_t P, arb_t Q, const hypgeom_t hyp, long n, long prec)
{
if (n < 1)
{
arb_zero(P);
arb_one(Q);
}
else
{
arb_t B, T;
arb_init(B);
arb_init(T);
bsplit_recursive_arb(P, Q, B, T, hyp, 0, n, 0, prec);
if (!arb_is_one(B))
arb_mul(Q, Q, B, prec);
arb_swap(P, T);
arb_clear(B);
arb_clear(T);
}
}
void
arb_hypgeom_infsum(arb_t P, arb_t Q, hypgeom_t hyp, long target_prec, long prec)
{
mag_t err, z;
long n;
mag_init(err);
mag_init(z);
mag_set_fmpz(z, hyp->P->coeffs + hyp->P->length - 1);
mag_div_fmpz(z, z, hyp->Q->coeffs + hyp->Q->length - 1);
if (!hyp->have_precomputed)
{
hypgeom_precompute(hyp);
hyp->have_precomputed = 1;
}
n = hypgeom_bound(err, hyp->r, hyp->boundC, hyp->boundD,
hyp->boundK, hyp->MK, z, target_prec);
arb_hypgeom_sum(P, Q, hyp, n, prec);
if (arf_sgn(arb_midref(Q)) < 0)
{
arb_neg(P, P);
arb_neg(Q, Q);
}
/* We have p/q = s + err i.e. (p + q*err)/q = s */
{
mag_t u;
mag_init(u);
arb_get_mag(u, Q);
mag_mul(u, u, err);
mag_add(arb_radref(P), arb_radref(P), u);
mag_clear(u);
}
mag_clear(z);
mag_clear(err);
}

99
mag.h
View file

@ -650,6 +650,105 @@ void mag_rfac_ui(mag_t z, ulong n);
/* TODO: document/test */
void mag_bernoulli_div_fac_ui(mag_t z, ulong n);
/* TODO: document/test */
void mag_set_fmpz_2exp_fmpz_lower(mag_t z, const fmpz_t man, const fmpz_t exp);
static __inline__ void
mag_set_ui(mag_t z, ulong x)
{
fmpz_t man, exp;
fmpz_init_set_ui(man, x);
*exp = 0;
mag_set_fmpz_2exp_fmpz(z, man, exp);
fmpz_clear(man);
}
static __inline__ void
mag_set_ui_lower(mag_t z, ulong x)
{
fmpz_t man, exp;
fmpz_init_set_ui(man, x);
*exp = 0;
mag_set_fmpz_2exp_fmpz_lower(z, man, exp);
fmpz_clear(man);
}
static __inline__ void
mag_set_fmpz(mag_t z, const fmpz_t x)
{
fmpz_t exp;
*exp = 0;
mag_set_fmpz_2exp_fmpz(z, x, exp);
}
static __inline__ void
mag_set_fmpz_lower(mag_t z, const fmpz_t x)
{
fmpz_t exp;
*exp = 0;
mag_set_fmpz_2exp_fmpz_lower(z, x, exp);
}
static __inline__ void
mag_mul_ui(mag_t z, const mag_t x, ulong y)
{
mag_t t;
mag_init(t);
mag_set_ui(t, y);
mag_mul(z, x, t);
mag_clear(t);
}
static __inline__ void
mag_mul_ui_lower(mag_t z, const mag_t x, ulong y)
{
mag_t t;
mag_init(t);
mag_set_ui_lower(t, y);
mag_mul_lower(z, x, t);
mag_clear(t);
}
static __inline__ void
mag_mul_fmpz(mag_t z, const mag_t x, const fmpz_t y)
{
mag_t t;
mag_init(t);
mag_set_fmpz(t, y);
mag_mul(z, x, t);
mag_clear(t);
}
static __inline__ void
mag_mul_fmpz_lower(mag_t z, const mag_t x, const fmpz_t y)
{
mag_t t;
mag_init(t);
mag_set_fmpz_lower(t, y);
mag_mul_lower(z, x, t);
mag_clear(t);
}
static __inline__ void
mag_div_ui(mag_t z, const mag_t x, ulong y)
{
mag_t t;
mag_init(t);
mag_set_ui_lower(t, y);
mag_div(z, x, t);
mag_clear(t);
}
static __inline__ void
mag_div_fmpz(mag_t z, const mag_t x, const fmpz_t y)
{
mag_t t;
mag_init(t);
mag_set_fmpz_lower(t, y);
mag_div(z, x, t);
mag_clear(t);
}
#ifdef __cplusplus
}
#endif

View file

@ -42,3 +42,22 @@ mag_set_fmpz_2exp_fmpz(mag_t z, const fmpz_t man, const fmpz_t exp)
_fmpz_add_fast(MAG_EXPREF(z), exp, cexp + MAG_BITS);
}
}
void
mag_set_fmpz_2exp_fmpz_lower(mag_t z, const fmpz_t man, const fmpz_t exp)
{
if (fmpz_is_zero(man))
{
mag_zero(z);
}
else
{
mp_limb_t m;
long cexp;
m = fmpz_abs_lbound_ui_2exp(&cexp, man, MAG_BITS);
MAG_MAN(z) = m;
_fmpz_add_fast(MAG_EXPREF(z), exp, cexp + MAG_BITS);
}
}