/* worst cases communicated by Jean-Michel Muller and Vincent Lefevre */
static int
check_worst_cases (void)
{
mpfr_t x;
mpfr_t y;
mpfr_init(x);
mpfr_set_prec (x, 53);
check_worst_case("4.44089209850062517562e-16", "1.00000000000000022204");
check_worst_case("6.39488462184069720009e-14", "1.00000000000006372680");
check_worst_case("1.84741111297455401935e-12", "1.00000000000184718907");
check_worst_case("1.76177628026265550074e-10", "1.00000000017617751702");
check3("1.76177628026265550074e-10", MPFR_RNDN, "1.00000000017617773906");
check_worst_case("7.54175277499595900852e-10", "1.00000000075417516676");
check3("7.54175277499595900852e-10", MPFR_RNDN, "1.00000000075417538881");
/* bug found by Vincent Lefe`vre on December 8, 1999 */
check3("-5.42410311287441459172e+02", MPFR_RNDN, "2.7176584868845723e-236");
/* further cases communicated by Vincent Lefe`vre on January 27, 2000 */
check3("-1.32920285897904911589e-10", MPFR_RNDN, "0.999999999867079769622");
check3("-1.44037948245738330735e-10", MPFR_RNDN, "0.9999999998559621072757");
check3("-1.66795910430705305937e-10", MPFR_RNDZ, "0.9999999998332040895832");
check3("-1.64310953745426656203e-10", MPFR_RNDN, "0.9999999998356891017792");
check3("-1.38323574826034659172e-10", MPFR_RNDZ, "0.9999999998616764251835");
check3("-1.23621668465115401498e-10", MPFR_RNDZ, "0.9999999998763783315425");
mpfr_set_prec (x, 601);
mpfr_set_str (x, "0.88b6ba510e10450edc258748bc9dfdd466f21b47ed264cdf24aa8f64af1f3fad9ec2301d43c0743f534b5aa20091ff6d352df458ef1ba519811ef6f5b11853534fd8fa32764a0a6d2d0dd20@0", 16, MPFR_RNDZ);
mpfr_init2 (y, 601);
mpfr_exp_2 (y, x, MPFR_RNDD);
mpfr_exp_3 (x, x, MPFR_RNDD);
if (mpfr_cmp (x, y))
{
printf ("mpfr_exp_2 and mpfr_exp_3 differ for prec=601\n");
printf ("mpfr_exp_2 gives ");
mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
printf ("\nmpfr_exp_3 gives ");
mpfr_out_str (stdout, 2, 0, x, MPFR_RNDN);
printf ("\n");
exit (1);
}
mpfr_set_prec (x, 13001);
mpfr_set_prec (y, 13001);
mpfr_urandomb (x, RANDS);
mpfr_exp_3 (y, x, MPFR_RNDN);
mpfr_exp_2 (x, x, MPFR_RNDN);
if (mpfr_cmp (x, y))
{
printf ("mpfr_exp_2 and mpfr_exp_3 differ for prec=13001\n");
exit (1);
}
mpfr_clear (x);
mpfr_clear (y);
return 0;
}
static void
compare_exp2_exp3 (int n)
{
mpfr_t x, y, z; int prec; mp_rnd_t rnd;
mpfr_init (x);
mpfr_init (y);
mpfr_init (z);
for (prec = 20; prec <= n; prec++)
{
mpfr_set_prec (x, prec);
mpfr_set_prec (y, prec);
mpfr_set_prec (z, prec);
mpfr_random (x);
rnd = (mp_rnd_t) RND_RAND();
mpfr_exp_2 (y, x, rnd);
mpfr_exp_3 (z, x, rnd);
if (mpfr_cmp (y,z))
{
printf ("mpfr_exp_2 and mpfr_exp_3 disagree for rnd=%s and\nx=",
mpfr_print_rnd_mode (rnd));
mpfr_print_binary (x);
puts ("");
printf ("mpfr_exp_2 gives ");
mpfr_print_binary (y);
puts ("");
printf ("mpfr_exp_3 gives ");
mpfr_print_binary (z);
puts ("");
exit (1);
}
}
/* bug found by Patrick Pe'lissier on 7 Jun 2004 */
prec = 203780;
mpfr_set_prec (x, prec);
mpfr_set_prec (z, prec);
mpfr_set_d (x, 3.0, GMP_RNDN);
mpfr_sqrt (x, x, GMP_RNDN);
mpfr_sub_ui (x, x, 1, GMP_RNDN);
mpfr_exp_3 (z, x, GMP_RNDN);
mpfr_clear (x);
mpfr_clear (y);
mpfr_clear (z);
}
static void
compare_exp2_exp3 (mpfr_prec_t p0, mpfr_prec_t p1)
{
mpfr_t x, y, z;
mpfr_prec_t prec;
mpfr_rnd_t rnd;
mpfr_init (x);
mpfr_init (y);
mpfr_init (z);
for (prec = p0; prec <= p1; prec ++)
{
mpfr_set_prec (x, prec);
mpfr_set_prec (y, prec);
mpfr_set_prec (z, prec);
do
mpfr_urandomb (x, RANDS);
while (MPFR_IS_ZERO (x)); /* 0 is handled by mpfr_exp only */
rnd = RND_RAND ();
mpfr_exp_2 (y, x, rnd);
mpfr_exp_3 (z, x, rnd);
if (mpfr_cmp (y,z))
{
printf ("mpfr_exp_2 and mpfr_exp_3 disagree for rnd=%s and\nx=",
mpfr_print_rnd_mode (rnd));
mpfr_print_binary (x);
puts ("");
printf ("mpfr_exp_2 gives ");
mpfr_print_binary (y);
puts ("");
printf ("mpfr_exp_3 gives ");
mpfr_print_binary (z);
puts ("");
exit (1);
}
}
mpfr_clear (x);
mpfr_clear (y);
mpfr_clear (z);
}
int
mpfr_exp (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
{
mpfr_exp_t expx;
mpfr_prec_t precy;
int inexact;
MPFR_SAVE_EXPO_DECL (expo);
MPFR_LOG_FUNC (("x[%#R]=%R rnd=%d", x, x, rnd_mode),
("y[%#R]=%R inexact=%d", y, y, inexact));
if (MPFR_UNLIKELY( MPFR_IS_SINGULAR(x) ))
{
if (MPFR_IS_NAN(x))
{
MPFR_SET_NAN(y);
MPFR_RET_NAN;
}
else if (MPFR_IS_INF(x))
{
if (MPFR_IS_POS(x))
MPFR_SET_INF(y);
else
MPFR_SET_ZERO(y);
MPFR_SET_POS(y);
MPFR_RET(0);
}
else
{
MPFR_ASSERTD(MPFR_IS_ZERO(x));
return mpfr_set_ui (y, 1, rnd_mode);
}
}
/* First, let's detect most overflow and underflow cases. */
{
mpfr_t e, bound;
/* We must extended the exponent range and save the flags now. */
MPFR_SAVE_EXPO_MARK (expo);
mpfr_init2 (e, sizeof (mpfr_exp_t) * CHAR_BIT);
mpfr_init2 (bound, 32);
inexact = mpfr_set_exp_t (e, expo.saved_emax, MPFR_RNDN);
MPFR_ASSERTD (inexact == 0);
mpfr_const_log2 (bound, expo.saved_emax < 0 ? MPFR_RNDD : MPFR_RNDU);
mpfr_mul (bound, bound, e, MPFR_RNDU);
if (MPFR_UNLIKELY (mpfr_cmp (x, bound) >= 0))
{
/* x > log(2^emax), thus exp(x) > 2^emax */
mpfr_clears (e, bound, (mpfr_ptr) 0);
MPFR_SAVE_EXPO_FREE (expo);
return mpfr_overflow (y, rnd_mode, 1);
}
inexact = mpfr_set_exp_t (e, expo.saved_emin, MPFR_RNDN);
MPFR_ASSERTD (inexact == 0);
inexact = mpfr_sub_ui (e, e, 2, MPFR_RNDN);
MPFR_ASSERTD (inexact == 0);
mpfr_const_log2 (bound, expo.saved_emin < 0 ? MPFR_RNDU : MPFR_RNDD);
mpfr_mul (bound, bound, e, MPFR_RNDD);
if (MPFR_UNLIKELY (mpfr_cmp (x, bound) <= 0))
{
/* x < log(2^(emin - 2)), thus exp(x) < 2^(emin - 2) */
mpfr_clears (e, bound, (mpfr_ptr) 0);
MPFR_SAVE_EXPO_FREE (expo);
return mpfr_underflow (y, rnd_mode == MPFR_RNDN ? MPFR_RNDZ : rnd_mode,
1);
}
/* Other overflow/underflow cases must be detected
by the generic routines. */
mpfr_clears (e, bound, (mpfr_ptr) 0);
MPFR_SAVE_EXPO_FREE (expo);
}
expx = MPFR_GET_EXP (x);
precy = MPFR_PREC (y);
/* if x < 2^(-precy), then exp(x) i.e. gives 1 +/- 1 ulp(1) */
if (MPFR_UNLIKELY (expx < 0 && (mpfr_uexp_t) (-expx) > precy))
{
mpfr_exp_t emin = __gmpfr_emin;
mpfr_exp_t emax = __gmpfr_emax;
int signx = MPFR_SIGN (x);
MPFR_SET_POS (y);
if (MPFR_IS_NEG_SIGN (signx) && (rnd_mode == MPFR_RNDD ||
rnd_mode == MPFR_RNDZ))
{
__gmpfr_emin = 0;
__gmpfr_emax = 0;
mpfr_setmax (y, 0); /* y = 1 - epsilon */
inexact = -1;
}
else
{
__gmpfr_emin = 1;
__gmpfr_emax = 1;
mpfr_setmin (y, 1); /* y = 1 */
if (MPFR_IS_POS_SIGN (signx) && (rnd_mode == MPFR_RNDU ||
rnd_mode == MPFR_RNDA))
{
mp_size_t yn;
int sh;
yn = 1 + (MPFR_PREC(y) - 1) / GMP_NUMB_BITS;
sh = (mpfr_prec_t) yn * GMP_NUMB_BITS - MPFR_PREC(y);
MPFR_MANT(y)[0] += MPFR_LIMB_ONE << sh;
inexact = 1;
}
else
inexact = -MPFR_FROM_SIGN_TO_INT(signx);
}
__gmpfr_emin = emin;
__gmpfr_emax = emax;
}
else /* General case */
{
if (MPFR_UNLIKELY (precy >= MPFR_EXP_THRESHOLD))
/* mpfr_exp_3 saves the exponent range and flags itself, otherwise
the flag changes in mpfr_exp_3 are lost */
inexact = mpfr_exp_3 (y, x, rnd_mode); /* O(M(n) log(n)^2) */
else
{
MPFR_SAVE_EXPO_MARK (expo);
inexact = mpfr_exp_2 (y, x, rnd_mode); /* O(n^(1/3) M(n)) */
MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, __gmpfr_flags);
MPFR_SAVE_EXPO_FREE (expo);
}
}
return mpfr_check_range (y, inexact, rnd_mode);
}