Tests fail for Maxima (HEAD) with ECL 8.12.0

Robert Dodier wrote:
> On Mon, Apr 6, 2009 at 6:53 AM, Raymond Toy <raymond.toy at stericsson.com> wrote:
>
>   
>>> Result:
>>>                                      1  20 sqrt(10)
>>> .3333333333333333 sqrt(10) (bessel_j(-, -----------)
>>>                                      3       3
>>>                                                1  20 sqrt(10)
>>>                                   + bessel_j(- -, -----------)) - airy_ai(- 10)
>>>                                                3       3
>>>
>>>
>>>       
>> This bug (or was it the next one?) has been there for a while. I only
>> see this with ecl; the other Lisps I've used (clisp, cmucl, gcl) work. I
>> been too lazy to look at it. :-(
>>     
>
> I'd like to get to the bottom of this but I'm not going to try to
> get it fixed in this release.
>
>   
>>> Input:
>>>        60
>>>       2   - 1
>>> float(-------) - 1
>>>          60
>>>         2
>>>
>>>
>>> Result:
>>> - 1.110223024625157e-16
>>>       
>
>   
>> This and similar failures are recent. I think it's a deficiency in how
>> ecl converts big ratios to floats using cl:float. I don't really want to
>> work around this bug just for ecl.
>>     
>
> I'm inclined to view this as a bug in ECL, although the CL spec
> for FLOAT is silent on what to do: it says "a float is returned that
> is mathematically equal to number". What if there is no such
> float? Doesn't say.
>   
The spec doesn't say how (+ a b) should be computed when a and b are
floats.  So what?  (Does any language specify that?) 

My take on this is that it has to do with the quality of the
implementation.  Implementations should try to do the "right" thing, but
are required to do so.

>
> It's a good thing the CL spec was written by superior beings
> and need never be revised or even questioned. Otherwise
> I would start ranting about what a disaster it is.
>   
Why the constant ranting about CL? 
>   
>> We could just borrow the code from cmucl (or others) that convert
>> ratios to floats.
>>     
>
> I'm inclined to lean on the ECL team to change their implementation
> of FLOAT. Let's get the ECL team to do copy the code from CMUCL.
>
>   
It would certainly be nice if this were fixed.  I already asked (as you
know) about it on the ecl list.

Ray