hiro/arb
1
0
Fork 0
mirror of https://github.com/vale981/arb synced 2025-03-05 09:21:38 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions

include error bound for pi_chudnovsky

Browse source
This commit is contained in:
Fredrik Johansson 2012-09-12 17:44:17 +02:00
parent 7e6bcb9ad6
commit baa622ecf1
1 changed files with 6 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
fmprb/const_pi_chudnovsky.c
View file

@ -29,7 +29,7 @@
#define CONST_B 545140134UL
#define CONST_C 640320UL
#define CONST_D 12UL
#define BITS_PER_TERM 47.1104131382158 /* log2(640320^3 / (2^6 * 3^3)) */
#define BITS_PER_TERM 47.110413138215842023 /* log2(640320^3 / (2^6 * 3^3)) */
void
chudnovsky_bsplit(fmprb_t G, fmprb_t P, fmprb_t Q, long a, long b, long wp, int cont)
@ -104,6 +104,7 @@ fmprb_const_pi_chudnovsky(fmprb_t x, long prec)
wp = prec + 32;
/* the summation is done up to N inclusive */
N = wp / BITS_PER_TERM + 1;
fmprb_init(G);
@ -121,9 +122,11 @@ fmprb_const_pi_chudnovsky(fmprb_t x, long prec)
fmprb_div(x, G, Q, wp);
/* TODO: add error term */
/* the actual truncation error is around -BITS_PER_TERM * (N+1),
so this bound is safe to compute using doubles */
fmprb_add_error_2exp_si(x, -BITS_PER_TERM * N + 1);
fmprb_clear(G);
fmprb_clear(P);
fmprb_clear(Q);
}
}