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refactoring; slightly speed up elementary functions for small input

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This commit is contained in:
Fredrik Johansson 2014-12-07 15:06:01 +01:00
parent e3f7ef1f66
commit 6d4cbbb86b
5 changed files with 33 additions and 23 deletions
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26
arb.h
View file

@ -1001,6 +1001,32 @@ void _arb_sin_cos_taylor_rs(mp_ptr ysin, mp_ptr ycos,
int _arb_get_mpn_fixed_mod_pi4(mp_ptr w, fmpz_t q, int * octant,
mp_limb_t * error, const arf_t x, mp_size_t wn);
static __inline__ mp_bitcnt_t
_arb_mpn_leading_zeros(mp_srcptr d, mp_size_t n)
{
mp_limb_t t;
mp_size_t zero_limbs;
mp_bitcnt_t bits;
zero_limbs = 0;
while (1)
{
t = d[n - zero_limbs - 1];
if (t != 0)
{
count_leading_zeros(bits, t);
return bits + FLINT_BITS * zero_limbs;
}
zero_limbs++;
if (zero_limbs == n)
return FLINT_BITS * zero_limbs;
}
}
#ifdef __cplusplus
}
#endif

7
arb/atan.c
View file

@ -28,7 +28,7 @@
#define TMP_ALLOC_LIMBS(size) TMP_ALLOC((size) * sizeof(mp_limb_t))
/* atan(x) = x + eps, |eps| < x^3*/
static void
void
arb_atan_eps(arb_t z, const arf_t x, long prec)
{
fmpz_t mag;
@ -41,7 +41,7 @@ arb_atan_eps(arb_t z, const arf_t x, long prec)
}
/* atan(x) = pi/2 - eps, eps < 1/x <= 2^(1-mag) */
static void
void
arb_atan_inf_eps(arb_t z, const arf_t x, long prec)
{
fmpz_t mag;
@ -140,6 +140,7 @@ _arf_set_mpn_fixed(arf_t z, mp_srcptr xp, mp_size_t xn, mp_size_t fixn, int nega
}
}
/* TODO: move out */
void
mag_add_ui_2exp_si(mag_t z, const mag_t x, ulong y, long e)
{
@ -332,7 +333,7 @@ arb_atan_arf(arb_t z, const arf_t x, long prec)
}
/* |w| <= 2^-r */
r = FLINT_BITS - FLINT_BIT_COUNT(w[wn-1]);
r = _arb_mpn_leading_zeros(w, wn);
/* N >= (wp-r)/(2r) */
N = (wp - r + (2*r-1)) / (2*r);

2
arb/exp.c
View file

@ -253,7 +253,7 @@ arb_exp_arf(arb_t z, const arf_t x, long prec, int minus_one)
}
/* |w| <= 2^-r */
r = FLINT_BITS - FLINT_BIT_COUNT(w[wn-1]);
r = _arb_mpn_leading_zeros(w, wn);
/* Choose number of terms N such that Taylor series truncation
error is <= 2^-wp */

19
arb/log.c
View file

@ -76,23 +76,6 @@ int _arf_set_mpn_fixed(arf_t z, mp_srcptr xp, mp_size_t xn, mp_size_t fixn, int
void mag_add_ui_2exp_si(mag_t z, const mag_t x, ulong y, long e);
static __inline__ mp_bitcnt_t
_mpn_leading_zeros(mp_srcptr w, mp_size_t wn)
{
mp_bitcnt_t r = 0;
while (wn > 0 && w[wn-1] == 0)
{
wn--;
r += FLINT_BITS;
}
if (wn > 0)
r += FLINT_BITS - FLINT_BIT_COUNT(w[wn-1]);
return r;
}
void
arb_log_arf_huge(arb_t z, const arf_t x, long prec)
{
@ -308,7 +291,7 @@ arb_log_arf(arb_t z, const arf_t x, long prec)
error += 3;
/* |w| <= 2^-r */
r = _mpn_leading_zeros(w, wn);
r = _arb_mpn_leading_zeros(w, wn);
/* N >= (wp-r)/(2r) */
N = (wp - r + (2*r-1)) / (2*r);

2
arb/sin_cos.c
View file

@ -291,7 +291,7 @@ arb_sin_cos_arf_new(arb_t zsin, arb_t zcos, const arf_t x, long prec)
}
/* |w| <= 2^-r */
r = FLINT_BITS - FLINT_BIT_COUNT(w[wn-1]);
r = _arb_mpn_leading_zeros(w, wn);
/* Choose number of terms N such that Taylor series truncation
error is <= 2^-wp */