Re: [open-axiom-devel] [fricas-devel] a really odd InputForm

[Waldek H. <he...@ma...>]

Bill Page wrote:
> 
> Try this:
> 
> (1) -> x^1.2
> 
>          5+-+
>    (1)  x\|x
> 
>                                                    Type: Expression Float
> 
> (2) -> %::InputForm
> 
>    (2)
>    (/
>      (+
>        (+  (float 0 0 2)
>          (*  (+ (+ (float 0 0 2) (* (float 1 0 2) x)) (float 0 0 2))
>            (**
>              (/  (+ (+ (float 0 0 2) (* (float 1 0 2) x)) (float 0 0 2))
>               (float 1 0 2))
>             (/ 1 (/ (float 5 0 2) (float 1 0 2))))
>            )
>          )
>       (float 0 0 2))
>     (float 1 0 2))
> 
>                                                    Type: InputForm
> 
> Using unparse or the most recent version of OpenAxiom this displays as:
> 
>    (2)
>   (float(0,0,2) + (float(0,0,2) + float(1,0,2)*x + float(0,0,2))*((float(0,0,2)
>    + float(1,0,2)*x + float(0,0,2))/float(1,0,2))^(1/(float(5,0,2)/float(1,0,2)
>   )) + float(0,0,2))/float(1,0,2)
> 
>                                                    Type: InputForm
> 
> (3) -> interpret(%)$InputForm
> 
>          5+-+
>    (3)  x\|x
> 
>                                                    Type: Expression Float
> 
> ----
> 
> Can anyone explain this odd result? Or this even one?
> 
> (4) -> (x^1.0)::InputForm
> 
>    (4)
>    (/ (+ (+ (float 0 0 2) (* (float 1 0 2) x)) (float 0 0 2)) (float 1 0 2))
> 
>                                                    Type: InputForm
> 

It looks like internal representation.
Expression is a quotient of two polynimials.  Denominator is
just constant polynimial equal 1.  In numerator you have two
variables (x and the root), but you also see explicitly
zero coefficients (that is a bit strange because internally
polynomial is sparse).  Root has two arguments, which again
are expressions...

-- 
                              Waldek Hebisch
he...@ma...