diff options
Diffstat (limited to 'src/sqrt.c')
| -rw-r--r-- | src/sqrt.c | 26 |
1 files changed, 11 insertions, 15 deletions
@@ -1,6 +1,6 @@ /* mpc_sqrt -- Take the square root of a complex number. -Copyright (C) 2002, 2008, 2009, 2010, 2011 INRIA +Copyright (C) 2002, 2008, 2009, 2010, 2011, 2012 INRIA This file is part of GNU MPC. @@ -329,11 +329,11 @@ mpc_sqrt (mpc_ptr a, mpc_srcptr b, mpc_rnd_t rnd) inex_im = inex_t; else { inex_im = -inex_t; - if ( (im_cmp > 0 && r == GMP_RNDD) - || (im_cmp < 0 && r == GMP_RNDU)) - MPFR_ADD_ONE_ULP (mpc_imagref (a)); - else - MPFR_SUB_ONE_ULP (mpc_imagref (a)); + /* im_cmp > 0 implies that Im(b) > 0, thus im_sgn = 0 + and r = GMP_RNDU. + im_cmp < 0 implies that Im(b) < 0, thus im_sgn = -1 + and r = GMP_RNDD. */ + MPFR_SUB_ONE_ULP (mpc_imagref (a)); } } else if (im_cmp > 0) { @@ -341,21 +341,17 @@ mpc_sqrt (mpc_ptr a, mpc_srcptr b, mpc_rnd_t rnd) inex_re = inex_t; else { inex_re = -inex_t; - if (r == GMP_RNDD) - MPFR_ADD_ONE_ULP (mpc_realref (a)); - else - MPFR_SUB_ONE_ULP (mpc_realref (a)); + /* im_cmp > 0 implies r = GMP_RNDU (see above) */ + MPFR_SUB_ONE_ULP (mpc_realref (a)); } } - else { + else { /* im_cmp < 0 */ if (rnd_t == r) inex_re = -inex_t; else { inex_re = inex_t; - if (r == GMP_RNDD) - MPFR_SUB_ONE_ULP (mpc_realref (a)); - else - MPFR_ADD_ONE_ULP (mpc_realref (a)); + /* im_cmp < 0 implies r = GMP_RNDD (see above) */ + MPFR_SUB_ONE_ULP (mpc_realref (a)); } } } |