Lines Matching refs:xr
135 mpfr_t r, s, xr, c;
185 mpfr_init2 (xr, m);
192 /* If |x| >= 4, first reduce x cmod (2*Pi) into xr, using mpfr_remainder:
195 (2) xr <- remainder (x, c) [precision m, nearest]
197 |xr - x - k c| <= 1/2ulp(xr) <= 2^(1-m)
199 Thus |xr - x - 2kPi| <= |k| |c - 2Pi| + 2^(1-m) <= 2^(2-m).
200 It follows |cos(xr) - cos(x)| <= 2^(2-m). */
205 mpfr_remainder (xr, x, c, MPFR_RNDN);
206 if (MPFR_IS_ZERO(xr))
208 /* now |xr| <= 4, thus r <= 16 below */
209 mpfr_mul (r, xr, xr, MPFR_RNDU); /* err <= 1 ulp */
214 /* now |x| < 4 (or xr if reduce = 1), thus |r| <= 16 */
281 mpfr_set_prec (xr, m);
290 mpfr_clear (xr);