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simplify zeta_ui_bsplit

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This commit is contained in:
Fredrik Johansson 2012-09-16 03:22:34 +02:00
parent d251d25bef
commit 36d9255b94
1 changed files with 3 additions and 17 deletions
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20
fmprb/zeta_ui_bsplit.c
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@ -213,23 +213,9 @@ fmprb_zeta_ui_bsplit(fmprb_t x, ulong s, long prec)
/* The error for eta(s) is bounded by 3/(3+sqrt(8))^n */
fmprb_add_error_2exp_si(sum->C, (long) (ERROR_A - ERROR_B * n + 1));
/* To get zeta(s), multiply by D = 1/(1 - 2^(1-s)) */
{
fmpz_t t;
fmpz_init(t);
for (i = wp; i >= 0; i -= (s - 1))
fmpz_setbit(t, i);
fmprb_set_fmpz(sum->D, t);
fmpz_sub_ui(fmpr_expref(fmprb_midref(sum->D)),
fmpr_expref(fmprb_midref(sum->D)), wp);
fmprb_add_error_2exp_si(sum->D, -wp);
fmpz_clear(t);
}
fmprb_mul(x, sum->C, sum->D, wp);
/* convert from eta(s) to zeta(s) */
fmprb_div_2expm1_ui(x, sum->C, s - 1, wp);
fmprb_mul_2exp_si(x, x, s - 1);
zeta_bsplit_clear(sum);
}