static mpfr_prec_t
get_prec_max (mpfr_t *tab, unsigned long n, mpfr_prec_t f)
{
mpfr_prec_t res;
mpfr_exp_t min, max;
unsigned long i;
i = 0;
while (MPFR_IS_ZERO (tab[i]))
{
i++;
if (i == n)
return MPFR_PREC_MIN; /* all values are 0 */
}
if (! mpfr_check (tab[i]))
{
printf ("tab[%lu] is not valid.\n", i);
exit (1);
}
MPFR_ASSERTN (MPFR_IS_FP (tab[i]));
min = max = MPFR_GET_EXP(tab[i]);
for (i++; i < n; i++)
{
if (! mpfr_check (tab[i]))
{
printf ("tab[%lu] is not valid.\n", i);
exit (1);
}
MPFR_ASSERTN (MPFR_IS_FP (tab[i]));
if (! MPFR_IS_ZERO (tab[i]))
{
if (MPFR_GET_EXP(tab[i]) > max)
max = MPFR_GET_EXP(tab[i]);
if (MPFR_GET_EXP(tab[i]) < min)
min = MPFR_GET_EXP(tab[i]);
}
}
res = max - min;
res += f;
res += __gmpfr_ceil_log2 (n) + 1;
return res;
}
static mp_prec_t get_prec_max (mpfr_t *tab, unsigned long n, mp_prec_t f)
{
mp_prec_t res;
mp_exp_t min, max;
unsigned long i;
min = max = MPFR_GET_EXP(tab[0]);
for (i = 1; i < n; i++)
{
if (MPFR_GET_EXP(tab[i]) > max)
max = MPFR_GET_EXP(tab[i]);
if (MPFR_GET_EXP(tab[i]) < min)
min = MPFR_GET_EXP(tab[i]);
}
res = max - min;
res += f;
res += __gmpfr_ceil_log2 (n) + 1;
return res;
}
static mpfr_prec_t
get_prec_max (mpfr_t *t, int n)
{
mpfr_exp_t e, min, max;
int i;
min = MPFR_EMAX_MAX;
max = MPFR_EMIN_MIN;
for (i = 0; i < n; i++)
if (MPFR_IS_PURE_FP (t[i]))
{
e = MPFR_GET_EXP (t[i]);
if (e > max)
max = e;
e -= MPFR_GET_PREC (t[i]);
if (e < min)
min = e;
}
return min > max ? MPFR_PREC_MIN /* no pure FP values */
: max - min + __gmpfr_ceil_log2 (n);
}
static mpfr_prec_t
get_prec_max (mpfr_t *tab, unsigned long n, mpfr_prec_t f)
{
mpfr_prec_t res;
mpfr_exp_t min, max;
unsigned long i;
for (i = 0; MPFR_IS_ZERO (tab[i]); i++)
MPFR_ASSERTD (i < n);
min = max = MPFR_GET_EXP(tab[i]);
for (i++; i < n; i++)
{
if (!MPFR_IS_ZERO (tab[i])) {
if (MPFR_GET_EXP(tab[i]) > max)
max = MPFR_GET_EXP(tab[i]);
if (MPFR_GET_EXP(tab[i]) < min)
min = MPFR_GET_EXP(tab[i]);
}
}
res = max - min;
res += f;
res += __gmpfr_ceil_log2 (n) + 1;
return res;
}
int
mpfr_atanh (mpfr_ptr y, mpfr_srcptr xt , mp_rnd_t rnd_mode)
{
int inexact = 0;
mpfr_t x;
mp_prec_t Nx = MPFR_PREC(xt); /* Precision of input variable */
/* Special cases */
if (MPFR_UNLIKELY( MPFR_IS_SINGULAR(xt) ))
{
/* atanh(NaN) = NaN, and atanh(+/-Inf) = NaN since tanh gives a result
between -1 and 1 */
if (MPFR_IS_NAN(xt) || MPFR_IS_INF(xt))
{
MPFR_SET_NAN(y);
MPFR_RET_NAN;
}
else /* necessarily xt is 0 */
{
MPFR_ASSERTD(MPFR_IS_ZERO(xt));
MPFR_SET_ZERO(y); /* atanh(0) = 0 */
MPFR_SET_SAME_SIGN(y,xt);
MPFR_RET(0);
}
}
/* Useless due to final mpfr_set
MPFR_CLEAR_FLAGS(y);*/
/* atanh(x) = NaN as soon as |x| > 1, and arctanh(+/-1) = +/-Inf */
if (MPFR_EXP(xt) > 0)
{
if (MPFR_EXP(xt) == 1 && mpfr_powerof2_raw (xt))
{
MPFR_SET_INF(y);
MPFR_SET_SAME_SIGN(y, xt);
MPFR_RET(0);
}
MPFR_SET_NAN(y);
MPFR_RET_NAN;
}
mpfr_init2 (x, Nx);
mpfr_abs (x, xt, GMP_RNDN);
/* General case */
{
/* Declaration of the intermediary variable */
mpfr_t t, te,ti;
/* Declaration of the size variable */
mp_prec_t Nx = MPFR_PREC(x); /* Precision of input variable */
mp_prec_t Ny = MPFR_PREC(y); /* Precision of input variable */
mp_prec_t Nt; /* Precision of the intermediary variable */
long int err; /* Precision of error */
/* compute the precision of intermediary variable */
Nt=MAX(Nx,Ny);
/* the optimal number of bits : see algorithms.ps */
Nt=Nt+4+__gmpfr_ceil_log2(Nt);
/* initialise of intermediary variable */
mpfr_init(t);
mpfr_init(te);
mpfr_init(ti);
/* First computation of cosh */
do
{
/* reactualisation of the precision */
mpfr_set_prec(t,Nt);
mpfr_set_prec(te,Nt);
mpfr_set_prec(ti,Nt);
/* compute atanh */
mpfr_ui_sub(te,1,x,GMP_RNDU); /* (1-xt)*/
mpfr_add_ui(ti,x,1,GMP_RNDD); /* (xt+1)*/
mpfr_div(te,ti,te,GMP_RNDN); /* (1+xt)/(1-xt)*/
mpfr_log(te,te,GMP_RNDN); /* ln((1+xt)/(1-xt))*/
mpfr_div_2ui(t,te,1,GMP_RNDN); /* (1/2)*ln((1+xt)/(1-xt))*/
/* error estimate see- algorithms.ps*/
/* err=Nt-__gmpfr_ceil_log2(1+5*pow(2,1-MPFR_EXP(t)));*/
err = Nt - (MAX (4 - MPFR_GET_EXP (t), 0) + 1);
/* actualisation of the precision */
Nt += 10;
}
while ((err < 0) || (!mpfr_can_round (t, err, GMP_RNDN, GMP_RNDZ,
Ny + (rnd_mode == GMP_RNDN))
|| MPFR_IS_ZERO(t)));
if (MPFR_IS_NEG(xt))
MPFR_CHANGE_SIGN(t);
inexact = mpfr_set (y, t, rnd_mode);
mpfr_clear(t);
mpfr_clear(ti);
mpfr_clear(te);
}
mpfr_clear(x);
return inexact;
}
int
mpfr_zeta (mpfr_t z, mpfr_srcptr s, mp_rnd_t rnd_mode)
{
mpfr_t z_pre, s1, y, p;
double sd, eps, m1, c;
long add;
mp_prec_t precz, prec1, precs, precs1;
int inex;
MPFR_GROUP_DECL (group);
MPFR_ZIV_DECL (loop);
MPFR_SAVE_EXPO_DECL (expo);
MPFR_LOG_FUNC (("s[%#R]=%R rnd=%d", s, s, rnd_mode),
("z[%#R]=%R inexact=%d", z, z, inex));
/* Zero, Nan or Inf ? */
if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (s)))
{
if (MPFR_IS_NAN (s))
{
MPFR_SET_NAN (z);
MPFR_RET_NAN;
}
else if (MPFR_IS_INF (s))
{
if (MPFR_IS_POS (s))
return mpfr_set_ui (z, 1, GMP_RNDN); /* Zeta(+Inf) = 1 */
MPFR_SET_NAN (z); /* Zeta(-Inf) = NaN */
MPFR_RET_NAN;
}
else /* s iz zero */
{
MPFR_ASSERTD (MPFR_IS_ZERO (s));
mpfr_set_ui (z, 1, rnd_mode);
mpfr_div_2ui (z, z, 1, rnd_mode);
MPFR_CHANGE_SIGN (z);
MPFR_RET (0);
}
}
/* s is neither Nan, nor Inf, nor Zero */
/* check tiny s: we have zeta(s) = -1/2 - 1/2 log(2 Pi) s + ... around s=0,
and for |s| <= 0.074, we have |zeta(s) + 1/2| <= |s|.
Thus if |s| <= 1/4*ulp(1/2), we can deduce the correct rounding
(the 1/4 covers the case where |zeta(s)| < 1/2 and rounding to nearest).
A sufficient condition is that EXP(s) + 1 < -PREC(z). */
if (MPFR_EXP(s) + 1 < - (mp_exp_t) MPFR_PREC(z))
{
int signs = MPFR_SIGN(s);
mpfr_set_si_2exp (z, -1, -1, rnd_mode); /* -1/2 */
if ((rnd_mode == GMP_RNDU || rnd_mode == GMP_RNDZ) && signs < 0)
{
mpfr_nextabove (z); /* z = -1/2 + epsilon */
inex = 1;
}
else if (rnd_mode == GMP_RNDD && signs > 0)
{
mpfr_nextbelow (z); /* z = -1/2 - epsilon */
inex = -1;
}
else
{
if (rnd_mode == GMP_RNDU) /* s > 0: z = -1/2 */
inex = 1;
else if (rnd_mode == GMP_RNDD)
inex = -1; /* s < 0: z = -1/2 */
else /* (GMP_RNDZ and s > 0) or GMP_RNDN: z = -1/2 */
inex = (signs > 0) ? 1 : -1;
}
return mpfr_check_range (z, inex, rnd_mode);
}
/* Check for case s= -2n */
if (MPFR_IS_NEG (s))
{
mpfr_t tmp;
tmp[0] = *s;
MPFR_EXP (tmp) = MPFR_EXP (s) - 1;
if (mpfr_integer_p (tmp))
{
MPFR_SET_ZERO (z);
MPFR_SET_POS (z);
MPFR_RET (0);
}
}
MPFR_SAVE_EXPO_MARK (expo);
/* Compute Zeta */
if (MPFR_IS_POS (s) && MPFR_GET_EXP (s) >= 0) /* Case s >= 1/2 */
inex = mpfr_zeta_pos (z, s, rnd_mode);
else /* use reflection formula
zeta(s) = 2^s*Pi^(s-1)*sin(Pi*s/2)*gamma(1-s)*zeta(1-s) */
{
precz = MPFR_PREC (z);
precs = MPFR_PREC (s);
/* Precision precs1 needed to represent 1 - s, and s + 2,
without any truncation */
precs1 = precs + 2 + MAX (0, - MPFR_GET_EXP (s));
sd = mpfr_get_d (s, GMP_RNDN) - 1.0;
if (sd < 0.0)
sd = -sd; /* now sd = abs(s-1.0) */
/* Precision prec1 is the precision on elementary computations;
it ensures a final precision prec1 - add for zeta(s) */
/* eps = pow (2.0, - (double) precz - 14.0); */
eps = __gmpfr_ceil_exp2 (- (double) precz - 14.0);
m1 = 1.0 + MAX(1.0 / eps, 2.0 * sd) * (1.0 + eps);
c = (1.0 + eps) * (1.0 + eps * MAX(8.0, m1));
/* add = 1 + floor(log(c*c*c*(13 + m1))/log(2)); */
add = __gmpfr_ceil_log2 (c * c * c * (13.0 + m1));
prec1 = precz + add;
prec1 = MAX (prec1, precs1) + 10;
MPFR_GROUP_INIT_4 (group, prec1, z_pre, s1, y, p);
MPFR_ZIV_INIT (loop, prec1);
for (;;)
{
mpfr_sub (s1, __gmpfr_one, s, GMP_RNDN);/* s1 = 1-s */
mpfr_zeta_pos (z_pre, s1, GMP_RNDN); /* zeta(1-s) */
mpfr_gamma (y, s1, GMP_RNDN); /* gamma(1-s) */
if (MPFR_IS_INF (y)) /* Zeta(s) < 0 for -4k-2 < s < -4k,
Zeta(s) > 0 for -4k < s < -4k+2 */
{
MPFR_SET_INF (z_pre);
mpfr_div_2ui (s1, s, 2, GMP_RNDN); /* s/4, exact */
mpfr_frac (s1, s1, GMP_RNDN); /* exact, -1 < s1 < 0 */
if (mpfr_cmp_si_2exp (s1, -1, -1) > 0)
MPFR_SET_NEG (z_pre);
else
MPFR_SET_POS (z_pre);
break;
}
mpfr_mul (z_pre, z_pre, y, GMP_RNDN); /* gamma(1-s)*zeta(1-s) */
mpfr_const_pi (p, GMP_RNDD);
mpfr_mul (y, s, p, GMP_RNDN);
mpfr_div_2ui (y, y, 1, GMP_RNDN); /* s*Pi/2 */
mpfr_sin (y, y, GMP_RNDN); /* sin(Pi*s/2) */
mpfr_mul (z_pre, z_pre, y, GMP_RNDN);
mpfr_mul_2ui (y, p, 1, GMP_RNDN); /* 2*Pi */
mpfr_neg (s1, s1, GMP_RNDN); /* s-1 */
mpfr_pow (y, y, s1, GMP_RNDN); /* (2*Pi)^(s-1) */
mpfr_mul (z_pre, z_pre, y, GMP_RNDN);
mpfr_mul_2ui (z_pre, z_pre, 1, GMP_RNDN);
if (MPFR_LIKELY (MPFR_CAN_ROUND (z_pre, prec1 - add, precz,
rnd_mode)))
break;
MPFR_ZIV_NEXT (loop, prec1);
MPFR_GROUP_REPREC_4 (group, prec1, z_pre, s1, y, p);
}
MPFR_ZIV_FREE (loop);
inex = mpfr_set (z, z_pre, rnd_mode);
MPFR_GROUP_CLEAR (group);
}
MPFR_SAVE_EXPO_FREE (expo);
return mpfr_check_range (z, inex, rnd_mode);
}
int
mpfr_eint (mpfr_ptr y, mpfr_srcptr x, mp_rnd_t rnd)
{
int inex;
mpfr_t tmp, ump;
mp_exp_t err, te;
mp_prec_t prec;
MPFR_SAVE_EXPO_DECL (expo);
MPFR_ZIV_DECL (loop);
MPFR_LOG_FUNC (("x[%#R]=%R rnd=%d", x, x, rnd),
("y[%#R]=%R inexact=%d", y, y, inex));
if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x)))
{
/* exp(NaN) = exp(-Inf) = NaN */
if (MPFR_IS_NAN (x) || (MPFR_IS_INF (x) && MPFR_IS_NEG(x)))
{
MPFR_SET_NAN (y);
MPFR_RET_NAN;
}
/* eint(+inf) = +inf */
else if (MPFR_IS_INF (x))
{
MPFR_SET_INF(y);
MPFR_SET_POS(y);
MPFR_RET(0);
}
else /* eint(+/-0) = -Inf */
{
MPFR_SET_INF(y);
MPFR_SET_NEG(y);
MPFR_RET(0);
}
}
/* eint(x) = NaN for x < 0 */
if (MPFR_IS_NEG(x))
{
MPFR_SET_NAN (y);
MPFR_RET_NAN;
}
MPFR_SAVE_EXPO_MARK (expo);
/* Since eint(x) >= exp(x)/x, we have log2(eint(x)) >= (x-log(x))/log(2).
Let's compute k <= (x-log(x))/log(2) in a low precision. If k >= emax,
then log2(eint(x)) >= emax, and eint(x) >= 2^emax, i.e. it overflows. */
mpfr_init2 (tmp, 64);
mpfr_init2 (ump, 64);
mpfr_log (tmp, x, GMP_RNDU);
mpfr_sub (ump, x, tmp, GMP_RNDD);
mpfr_const_log2 (tmp, GMP_RNDU);
mpfr_div (ump, ump, tmp, GMP_RNDD);
/* FIXME: We really need mpfr_set_exp_t and mpfr_cmp_exp_t functions. */
MPFR_ASSERTN (MPFR_EMAX_MAX <= LONG_MAX);
if (mpfr_cmp_ui (ump, __gmpfr_emax) >= 0)
{
mpfr_clear (tmp);
mpfr_clear (ump);
MPFR_SAVE_EXPO_FREE (expo);
return mpfr_overflow (y, rnd, 1);
}
/* Init stuff */
prec = MPFR_PREC (y) + 2 * MPFR_INT_CEIL_LOG2 (MPFR_PREC (y)) + 6;
/* eint() has a root 0.37250741078136663446..., so if x is near,
already take more bits */
if (MPFR_GET_EXP(x) == -1) /* 1/4 <= x < 1/2 */
{
double d;
d = mpfr_get_d (x, GMP_RNDN) - 0.37250741078136663;
d = (d == 0.0) ? -53 : __gmpfr_ceil_log2 (d);
prec += -d;
}
mpfr_set_prec (tmp, prec);
mpfr_set_prec (ump, prec);
MPFR_ZIV_INIT (loop, prec); /* Initialize the ZivLoop controler */
for (;;) /* Infinite loop */
{
/* We need that the smallest value of k!/x^k is smaller than 2^(-p).
The minimum is obtained for x=k, and it is smaller than e*sqrt(x)/e^x
for x>=1. */
if (MPFR_GET_EXP (x) > 0 && mpfr_cmp_d (x, ((double) prec +
0.5 * (double) MPFR_GET_EXP (x)) * LOG2 + 1.0) > 0)
err = mpfr_eint_asympt (tmp, x);
else
{
err = mpfr_eint_aux (tmp, x); /* error <= 2^err ulp(tmp) */
te = MPFR_GET_EXP(tmp);
mpfr_const_euler (ump, GMP_RNDN); /* 0.577 -> EXP(ump)=0 */
mpfr_add (tmp, tmp, ump, GMP_RNDN);
/* error <= 1/2 + 1/2*2^(EXP(ump)-EXP(tmp)) + 2^(te-EXP(tmp)+err)
<= 1/2 + 2^(MAX(EXP(ump), te+err+1) - EXP(tmp))
<= 2^(MAX(0, 1 + MAX(EXP(ump), te+err+1) - EXP(tmp))) */
err = MAX(1, te + err + 2) - MPFR_GET_EXP(tmp);
err = MAX(0, err);
te = MPFR_GET_EXP(tmp);
mpfr_log (ump, x, GMP_RNDN);
mpfr_add (tmp, tmp, ump, GMP_RNDN);
/* same formula as above, except now EXP(ump) is not 0 */
err += te + 1;
if (MPFR_LIKELY (!MPFR_IS_ZERO (ump)))
err = MAX (MPFR_GET_EXP (ump), err);
err = MAX(0, err - MPFR_GET_EXP (tmp));
}
if (MPFR_LIKELY (MPFR_CAN_ROUND (tmp, prec - err, MPFR_PREC (y), rnd)))
break;
MPFR_ZIV_NEXT (loop, prec); /* Increase used precision */
mpfr_set_prec (tmp, prec);
mpfr_set_prec (ump, prec);
}
MPFR_ZIV_FREE (loop); /* Free the ZivLoop Controler */
inex = mpfr_set (y, tmp, rnd); /* Set y to the computed value */
mpfr_clear (tmp);
mpfr_clear (ump);
MPFR_SAVE_EXPO_FREE (expo);
return mpfr_check_range (y, inex, rnd);
}
/* evaluates erf(x) using the expansion at x=0:
erf(x) = 2/sqrt(Pi) * sum((-1)^k*x^(2k+1)/k!/(2k+1), k=0..infinity)
Assumes x is neither NaN nor infinite nor zero.
Assumes also that e*x^2 <= n (target precision).
*/
static int
mpfr_erf_0 (mpfr_ptr res, mpfr_srcptr x, double xf2, mpfr_rnd_t rnd_mode)
{
mpfr_prec_t n, m;
mpfr_exp_t nuk, sigmak;
double tauk;
mpfr_t y, s, t, u;
unsigned int k;
int log2tauk;
int inex;
MPFR_GROUP_DECL (group);
MPFR_ZIV_DECL (loop);
n = MPFR_PREC (res); /* target precision */
/* initial working precision */
m = n + (mpfr_prec_t) (xf2 / LOG2) + 8 + MPFR_INT_CEIL_LOG2 (n);
MPFR_GROUP_INIT_4(group, m, y, s, t, u);
MPFR_ZIV_INIT (loop, m);
for (;;)
{
mpfr_mul (y, x, x, MPFR_RNDU); /* err <= 1 ulp */
mpfr_set_ui (s, 1, MPFR_RNDN);
mpfr_set_ui (t, 1, MPFR_RNDN);
tauk = 0.0;
for (k = 1; ; k++)
{
mpfr_mul (t, y, t, MPFR_RNDU);
mpfr_div_ui (t, t, k, MPFR_RNDU);
mpfr_div_ui (u, t, 2 * k + 1, MPFR_RNDU);
sigmak = MPFR_GET_EXP (s);
if (k % 2)
mpfr_sub (s, s, u, MPFR_RNDN);
else
mpfr_add (s, s, u, MPFR_RNDN);
sigmak -= MPFR_GET_EXP(s);
nuk = MPFR_GET_EXP(u) - MPFR_GET_EXP(s);
if ((nuk < - (mpfr_exp_t) m) && ((double) k >= xf2))
break;
/* tauk <- 1/2 + tauk * 2^sigmak + (1+8k)*2^nuk */
tauk = 0.5 + mul_2exp (tauk, sigmak)
+ mul_2exp (1.0 + 8.0 * (double) k, nuk);
}
mpfr_mul (s, x, s, MPFR_RNDU);
MPFR_SET_EXP (s, MPFR_GET_EXP (s) + 1);
mpfr_const_pi (t, MPFR_RNDZ);
mpfr_sqrt (t, t, MPFR_RNDZ);
mpfr_div (s, s, t, MPFR_RNDN);
tauk = 4.0 * tauk + 11.0; /* final ulp-error on s */
log2tauk = __gmpfr_ceil_log2 (tauk);
if (MPFR_LIKELY (MPFR_CAN_ROUND (s, m - log2tauk, n, rnd_mode)))
break;
/* Actualisation of the precision */
MPFR_ZIV_NEXT (loop, m);
MPFR_GROUP_REPREC_4 (group, m, y, s, t, u);
}
MPFR_ZIV_FREE (loop);
inex = mpfr_set (res, s, rnd_mode);
MPFR_GROUP_CLEAR (group);
return inex;
}
