I don't recall any argument about something being on or off -- what do you
have in mind?
That mixed arithmetic between rationals and floats converts to floats?
Yes, that is Maxima's behavior and as far as I know that can't be turned
off -- so there is no 'default'. Unfortunately, constant expressions which
are not literal rationals don't participate in this behavior: sqrt(5.0) -
sqrt(5) does not simplify to 0. In my opinion, it should.
-s
On Thu, Nov 10, 2011 at 16:15, cheater cheater <cheater00 at gmail.com> wrote:
> The only thing that was argued to be or not be on, which is:
>
> > The only way 0.1 - 1/10 is computed as zero is if the user forces exact
> > numbers be converted to nearby floating-point numbers. In this case the
> > two
> > values coincide.
>
> Cheers!
>
> On Thu, Nov 10, 2011 at 20:14, Stavros Macrakis <macrakis at alum.mit.edu>
> wrote:
> > *What* "seems to be the default"?
> > -s
> > On Thu, Nov 10, 2011 at 13:15, cheater cheater <cheater00 at gmail.com>
> wrote:
> >>
> >> That seems to be the default then, doesn't it?
> >>
> >> Cheers
> >>
> >> On Thu, Nov 10, 2011 at 19:04, Richard Fateman
> >> <fateman at eecs.berkeley.edu> wrote:
> >> > On 11/10/2011 9:30 AM, cheater cheater wrote:
> >> >>
> >> >> Hi Rene,
> >> >> they do:
> >> >>
> >> >> (%i1) sqrt(0.1)-sqrt(1/10);
> >> >> (%o1) .3162277660168379 - 1/sqrt(10)
> >> >> (%i2) ev(sqrt(0.1)-sqrt(1/10),numer);
> >> >> (%o2) 0.0
> >> >>
> >> >> You just have to invoke numeric evaluation.
> >> >>
> >> >> Hope this helps
> >> >
> >> > Actually, 0.1 is not equal to 1/10.
> >> >
> >> > 0.1 is a floating point number which is converted to double-float
> >> > binary,
> >> > in which internal form it is
> >> > exactly equal to 3602879701896397/2^55.
> >> >
> >> > This is NOT exactly equal to 1/10. They differ by 1/180143985094819840
> >> > or
> >> > 1/(5*2^55).
> >> >
> >> > The only way 0.1 - 1/10 is computed as zero is if the user forces
> exact
> >> > numbers be converted to nearby floating-point numbers. In this case
> the
> >> > two
> >> > values coincide.
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >> On Thu, Nov 10, 2011 at 17:51, rene kaelin<renekaelin at gmx.ch>
> wrote:
> >> >>>
> >> >>> Dear maxima users
> >> >>> Why don't both expressions simplify to zero?
> >> >>> (%i1) sqrt(0.1)-sqrt(1/10);
> >> >>> (%o1) .3162277660168379-1/sqrt(10)
> >> >>> (%i2) 0.1^0.5-(1/10)^0.5;
> >> >>> (%o2) 0.0
> >> >>> Manual:
> >> >>> Function: SQRT (X)the square root of X. It is represented internally
> >> >>> by
> >> >>> X^(1/2). Also see ROOTSCONTRACT. RADEXPAND[TRUE] - if TRUE will
> cause
> >> >>> nth
> >> >>> roots of factors of a product which are powers of n to be pulled
> >> >>> outside
> >> >>> of
> >> >>> the radical, e.g. SQRT(16*X^2) will become 4*X only if RADEXPAND is
> >> >>> TRUE.
> >> >>> Maxima version: 5.21.1Maxima build date: 16:28 5/16/2010Host type:
> >> >>> i686-apple-darwin10.3.0Lisp implementation type: SBCLLisp
> >> >>> implementation
> >> >>> version: 1.0.38
> >> >>>
> >> >>>
> >> >>> _______________________________________________
> >> >>> Maxima mailing list
> >> >>> Maxima at math.utexas.edu
> >> >>> http://www.math.utexas.edu/mailman/listinfo/maxima
> >> >>>
> >> >>>
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> >> >> http://www.math.utexas.edu/mailman/listinfo/maxima
> >> >
> >> >
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> >
> >
>