[Firebird-devel] rand function

[Adriano d. S. F. <adr...@uo...>]

All,

It appears that rand UDF (rand from MSVC7) is very bad.

create table t (n double precision not null);

set term !;

create procedure sp_fill (n integer)
as
begin
    while (n > 0) do
    begin
       n = n - 1;
       insert into t (n) values (rand());
    end
end!

set term ;!

execute procedure sp_fill (100000);

select first 20 n, count(*) from t group by n order by 2 desc;

                      N        COUNT
======================= ============
     0.2249519333475753           12
     0.5224463637195960           12
     0.6654560991241187           12
   0.003631702627643666           11
    0.09149449140903958           11
     0.1555528427991577           11
     0.3594775231177709           11
     0.2959074678792688           11
     0.4945524460585345           11
     0.5142368846705527           11
    0.01181066316721091           10
   0.009918515579699088           10
    0.06979583117160558           10
     0.1017487105929746           10
    0.09811700796533097           10
     0.1127353740043336           10
     0.1166417432172613           10
     0.1553392132328257           10
     0.2326731162450026           10
     0.2409741508224738           10


Or am I missing something?


Adriano