RE: [Axiom-developer] Compiler coercion and DoubleFloat

[Vanuxem Grégory]

Hi,


Le mardi 28 février 2006 à 01:00 +0100, Bill Page a écrit :

> That's cool.
> 
> Does '$useBFasDefault:=false' globally change the representation
> of DoubleFloat to lisp double-float?

No, the representation of DoubleFloat is already a lisp
double-float as far as i know.

> What is the advantage of lisp double-float over Axiom's
> DoubleFloat? Higher precision?
> 
> (1) -> precision()$Float
> 
>    (1)  68
>    Type: PositiveInteger
> 
> Precisioni of Float is adjustable but the following are fixed.
> 
> (2) -> precision()$DoubleFloat
> 
>    (2)  53
>    Type: PositiveInteger
> 
> (3) -> precision()$MachineFloat
> 
>    (3)  16
>    Type: PositiveInteger
> 
> -------
> 
> If I set $useBFasDefault in the Axiom interpreter I get the
> following error:
> 
> (1) -> )boot $useBFasDefault:=false
> (SPADLET |$useBFasDefault| NIL)
> Value = NIL
> (1) -> two4: DoubleFloat := 24.0
> 
>    >> System error:
>    Caught fatal error [memory may be damaged]
> 
> protected-symbol-warn called with (NIL)

Yes I have seen and i don't know why.
It isn't a problem for me since i change the value
of $useBFasDefault only in spad code and revert it at the end of
the code (i.e. just for the 'translation' of spad into lisp).

> -------
> 
> So I suppose you have some specific application of this in the
> SPAD compiler?

Yes

Cheers,

Greg

> 
> Regards,
> Bill Page.
> 
> 
> 
> 
>