Re: [HACKERS] regression bigtest needs very long time

Hi,

wieck(at)debis(dot)com (Jan Wieck) wrote:
>
> The complex functions (LN, LOG, EXP, etc.) where added to
> NUMERIC for the case someone really needs higher precision
> than float8. The numeric_big test simply ensures that
> someone really get's the CORRECT result when computing a
> logarithm up to hundreds of digits. All the expected results
> fed into the tables are computed by scripts using bc(1) with
> a precision 200 digits higher than that used in the test
> itself. So I'm pretty sure NUMERIC returns a VERY GOOD
> approximation if I ask for the square root of 2 with 1000
> digits.

I was able to understand the specification for the NUMERIC
data type. But, I can not yet understand the specification of
the regression normal test.

File :"src/regress/sql/numeric.sql"
Function : LN(ABS(round(val,300)))
----> LN(ABS(round(val,30))) <---- My hope

Please teach me,

Is there a difference of the calculation algorithm between 30
and 300 digits ?

Is there a difference of something like CPU-dependence or like
compiler-dependence between 30 and 300 digits ?

# If the answer is "NO", I think that the 300 digits case is
not necessary once you are sure that it works, because

1. the 30 digits case is equivalent to the 300 digits case.
2. the 300 digits case is slow.
3. It is sufficiently large value even in 30 digits.

--
Regards.

SAKAIDA Masaaki <sakaida(at)psn(dot)co(dot)jp>
Osaka, Japan