Re: [Maxima-discuss] bfloat issue

[Barton W. <wi...@un...>]

If you would like to experiment and possibly (likely) break stuff, try:


    (%i1) zeroa() := box('zeroa, gensym())$

    (%i2) zerob() := box('zerob, gensym())$

    (%i3) inf() :=  box('inf, gensym())$

    (%i4) minf() :=  box('minf, gensym())$

    (%i5) map('nofix, [zeroa, zerob, inf, minf])$

    (%i6) box_p(e) := not mapatom(e) and is(nounify(inpart(e,0))=nounify('mlabox))$

    (%i7) baz(a,b) := csign(a) = 'pos and box_p(b)$

    (%i8) matchdeclare([a,b],true)$

    (%i9) let(a*b, zeroa, baz, a,b);
    (%o9) a*b --> zeroa() where baz(a,b)

    (%i10) z : 7*zeroa;
    (%o10) 7*zeroa

    (%i11) z-z;
    (%o11) 0

    (%i12) letsimp(z);
    (%o12) zeroa

    (%i13) z + zeroa;
    (%o13) 7*zeroa+zeroa

    (%i14) letsimp(%);
    (%o14) zeroa+zeroa

    (%i15) %-%;
    (%o15) zeroa-zeroa


Don't know why that didn't simplify to zero...

    (%i16) expand(%,0,0);
    (%o16) 0

    (%i17) inf - inf;
    (%o17) inf-inf


--Barton
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