Subject | how random is rand() (2nd post) |
---|---|
Author | duilio_fos |
Post date | 2002-09-04T07:56:49Z |
enclosed are the results I got by the following SQL code:
SELECT rand()*100 FROM rdb$database
50.26
50.48
50.64
50.79
50.92
51.06
(only 2 decimals are written here)
Given the definition of the rand() function, I was expecting random
values 0<=V<100 .
What I got are similar, slightly increasing values. Surely not random
values.
Am I bad or is the rand() function bad ?
TIA
Duilio Foschi
PS I am using FB v. 1.0 .
The rand() function is declared as
DECLARE EXTERNAL FUNCTION rand
RETURNS DOUBLE PRECISION BY VALUE
ENTRY_POINT 'IB_UDF_rand' MODULE_NAME 'ib_udf';
SELECT rand()*100 FROM rdb$database
50.26
50.48
50.64
50.79
50.92
51.06
(only 2 decimals are written here)
Given the definition of the rand() function, I was expecting random
values 0<=V<100 .
What I got are similar, slightly increasing values. Surely not random
values.
Am I bad or is the rand() function bad ?
TIA
Duilio Foschi
PS I am using FB v. 1.0 .
The rand() function is declared as
DECLARE EXTERNAL FUNCTION rand
RETURNS DOUBLE PRECISION BY VALUE
ENTRY_POINT 'IB_UDF_rand' MODULE_NAME 'ib_udf';