=?ISO-8859-1?Q?Daniel_V=E1zquez?= <daniel2d2...@gmail.com> writes: > Please can someone tell me why this behavior? Thx!!
You're confusing numeric and double precision; in particular this calculation is *not* being done in float8, but numeric: > # select (0.766238989559398 * 0.766238989559398 * 1 + 0.642555686986733 * > 0.642555686986733) calc; > (*) Why this calculation produces 1 and not 0.999999999999999633651488135693 Actually, it's not producing 1, but a smidgen more: regression=# set extra_float_digits TO 3; SET regression=# select ( cast ( cos(radians(39.9826557)) * cos(radians(39.9826557)) * cos(radians(-0.04773120000004383) - radians(-0.04773120000004383)) + sin(radians(39.9826557)) * sin(radians(39.9826557)) as double precision ) ); float8 --------------------- 1.00000000000000022 (1 row) You've got roundoff error either way, but this way happens to be in the direction that makes acos() complain. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers