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*To*: Alex Shinn <alexshinn@x>*Subject*: Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0*From*: Mark H Weaver <mhw@x>*Date*: Fri, 21 Dec 2012 14:47:31 -0500*Cc*: John Cowan <cowan@x>, scheme-reports <scheme-reports@x>*In-reply-to*: <CAMMPzYMQVzkQFLsgcYAWZaFO__Y13T_kOXD+CrLqVXPQOcjXGw@mail.gmail.com> (Alex Shinn's message of "Fri, 21 Dec 2012 21:35:20 +0900")*References*: <878v8z5iq8.fsf@tines.lan> <874njn5b65.fsf@tines.lan> <20121215204015.GG13463@mercury.ccil.org> <87obhv3ts0.fsf@tines.lan> <20121215231548.GC10312@mercury.ccil.org> <87bodu4r0r.fsf@tines.lan> <20121216041031.GE10312@mercury.ccil.org> <87pq25yh5s.fsf@tines.lan> <20121219221955.GH4477@mercury.ccil.org> <87d2y5y6fb.fsf@tines.lan> <20121221055315.GB28661@mercury.ccil.org> <87y5grsrvm.fsf@tines.lan> <CAMMPzYMQVzkQFLsgcYAWZaFO__Y13T_kOXD+CrLqVXPQOcjXGw@mail.gmail.com>

Alex Shinn <alexshinn@x> writes: > The result you're seeing is because make-rectangular > is defined: > > (define (make-rectangular x y) > (+ x (* y (sqrt -1)))) > > in order to keep the number of primitives to a minimum, > and the sign on the zero gets lost in the arithmetic. In that case, the bug is in 'make-rectangular'. > The standard is silent on whether or not this is allowed > for make-rectangular, The R7RS-draft-8 states in the definition of 'make-rectangular': Then all of: (make-rectangular x_1 x_2) => z [...] (real-part z) => x_1 (imag-part z) => x_2 [...] are true, [...] > but note in Chibi the value -0.0 is > only supported as a place holder and in the future will > be removed in favor of not underflowing. Okay. IMO, it's unwise to allow inexacts to use unbounded amounts of memory and computation time, and I could easily construct example computations that work well on most implementations but that slow down to a crawl and/or run out of memory in your proposed representation, but Chibi is your baby and that's your choice. In the meantime, Chibi is not conformant to the requirements of R7RS-draft-8 in this respect. Mark _______________________________________________ Scheme-reports mailing list Scheme-reports@x http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports

**Follow-Ups**:**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Alex Shinn <alexshinn@x>

**References**:**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Mark H Weaver <mhw@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Mark H Weaver <mhw@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*John Cowan <cowan@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Mark H Weaver <mhw@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*John Cowan <cowan@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Mark H Weaver <mhw@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*John Cowan <cowan@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Mark H Weaver <mhw@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*John Cowan <cowan@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Mark H Weaver <mhw@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*John Cowan <cowan@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Mark H Weaver <mhw@x>

**Re: [Scheme-reports] Strong win later reversed: Real numbers have imaginary part #e0***From:*Alex Shinn <alexshinn@x>

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