float erf (%i) ??



On 2/15/12 10:29 AM, John Lapeyre wrote:
>>
>> I don't think this is the right thing to do.  Why?  Because:
>>
>> erf(%i),numer;
>>
>> returns 1.650425758797543 %i.
>>
>> How did I know?  I cheated and looked at the code for
>> float-numerical-eval-p which has a check for $numer.
> 
>> Perhaps %erf needs a 'subc property added to its property list?
> 
>  I don't understand how that works, except that it has something
>  to to with creating a subcontext.

My mistake.  I was wondering how float(sin(%i)) will return a numerical
result when float(erf(%i)) does not.  We're missing something, but I
don't know what that is right now.

>  It seems there should be a way of having float(erf(%i)) work that is
>  independent of how erf simplifies to erfi.

Agreed.  There is still the separate and long-standing issue of how
float and numer behave differently in rather unexpected ways.

Ray