If you want to verbify a particular function application, you can use
ev(..., <funcname>) instead of ev(..., nouns) (which verbifies *all*
nouns).
And as usual I'd recommend that you avoid 'ev' in general as much as
possible. Unfortunately, there are still many things that can only be
done with 'ev'.
-s
On Wed, May 13, 2009 at 3:18 PM, Oliver Kullmann
<O.Kullmann at swansea.ac.uk> wrote:
> aha; thanks!
>
> Then I guess I avoid this usage-path better altogether.
>
> Just to mention where this application comes from:
> I'm creating Ramsey-graphs, where the vertices are
> subsets, say {1,3,5}. Now it is very convenient to
> let these subsets just be the vertices (as in ordinary
> mathematics). However,
> at a certain point, I need to standardise these
> vertices to names 1,2,3,... . Now a possibility
> to do this could be to use rv(1,3,5) instead of
> {1,3,5} as vertex-name, and then performing the
> standardisation of vertex-names by just evaluating
> the whole graph (a pair of vertex- and edge-list)
> as done below (where rcs ranks subsets), defining
> rv inside the evaluation (while otherwise it's not
> evaluated).
>
> But perhaps it's safer, if such problems are possible,
> to have two functions for creating the respective graphs,
> one using {1,3,5} as vertex-name, the other directly its rank.
>
> Oliver
>
>
> On Wed, May 13, 2009 at 02:37:31PM -0400, Stavros Macrakis wrote:
>> This is a bug in 'binomial', nothing to do with ev.
>>
>> ? ? binomial(5,1) => 5
>> ? ? binomial(5,2) => 10
>>
>> ? ? binomial(5,1), nouns => 5
>> ? ? binomial(5,2), nouns => 10.0
>>
>> ? ? (verbify(binomial))(5,1) => 5
>> ? ? (verbify(binomial))(5,2) => 10.0
>>
>> This is left over from the old notion that the verb provides
>> floating-point evaluation.
>>
>> See mlisp.lisp: $binomial.
>>
>> ? ? ? ? ? ? ? ?-s
>>
>> On Wed, May 13, 2009 at 2:18 PM, Oliver Kullmann
>> <O.Kullmann at swansea.ac.uk> wrote:
>> > Hello,
>> >
>> > Maxima 5.18.1 http://maxima.sourceforge.net
>> > Using Lisp ECL 9.4.1
>> > declare(rv,noun)$
>> > rcs(S) := block([L : listify(S)],
>> > ?apply("+",create_list(binomial(L[i]-1,i), i,1,length(L))) + 1)$
>> > (%i4) ev(rv(1,4),rv([L]):=rcs(setify(L)),nouns);
>> > (%o4) 4
>> > (%i5) ev(rv(1,5),rv([L]):=rcs(setify(L)),nouns);
>> > (%o5) 7.0
>> > (%i6) rcs({1,5});
>> > (%o6) 7
>> >
>> > I hope you see the disaster: o6 is correct, and should be the same
>> > as o5, but somehow suddenly the result is turned into a floating-point
>> > number (which depends on the values --- doesn't happen with o4).
>> >
>> > I guess I should submit this as a bug, but wanted to hear some comments first.
>> >
>> > (Workarounds? Currently the above behaviour blocks a whole development; but
>> > using floor doesn't seem safe ...)
>> >
>> > Oliver
>> >
>> > _______________________________________________
>> > Maxima mailing list
>> > Maxima at math.utexas.edu
>> > http://www.math.utexas.edu/mailman/listinfo/maxima
>> >
>
> --
> Dr. Oliver Kullmann
> Computer Science Department
> Swansea University
> Faraday Building, Singleton Park
> Swansea SA2 8PP, UK
> http://cs.swan.ac.uk/~csoliver/
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>