diff options
Diffstat (limited to 'src/bin/pgbench/pgbench.c')
| -rw-r--r-- | src/bin/pgbench/pgbench.c | 24 |
1 files changed, 3 insertions, 21 deletions
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c index 18d9c94ebd3..9c12ffaea93 100644 --- a/src/bin/pgbench/pgbench.c +++ b/src/bin/pgbench/pgbench.c @@ -1136,8 +1136,8 @@ getGaussianRand(pg_prng_state *state, int64 min, int64 max, Assert(parameter >= MIN_GAUSSIAN_PARAM); /* - * Get user specified random number from this loop, with -parameter < - * stdev <= parameter + * Get normally-distributed random number in the range -parameter <= stdev + * < parameter. * * This loop is executed until the number is in the expected range. * @@ -1149,25 +1149,7 @@ getGaussianRand(pg_prng_state *state, int64 min, int64 max, */ do { - /* - * pg_prng_double generates [0, 1), but for the basic version of the - * Box-Muller transform the two uniformly distributed random numbers - * are expected to be in (0, 1] (see - * https://en.wikipedia.org/wiki/Box-Muller_transform) - */ - double rand1 = 1.0 - pg_prng_double(state); - double rand2 = 1.0 - pg_prng_double(state); - - /* Box-Muller basic form transform */ - double var_sqrt = sqrt(-2.0 * log(rand1)); - - stdev = var_sqrt * sin(2.0 * M_PI * rand2); - - /* - * we may try with cos, but there may be a bias induced if the - * previous value fails the test. To be on the safe side, let us try - * over. - */ + stdev = pg_prng_double_normal(state); } while (stdev < -parameter || stdev >= parameter); |