[Date Index]
[Thread Index]
[Author Index]
Re: Radicals simplify
Andrzej Kozlowski wrote:
> Yes, but Adam Strzebonski has already posted here the default
> CoplexityFunction in the past, and knowing it really wont help you much:
>
>
> SimplifyCount[p_] :=
> If[Head[p]===Symbol, 1,
> If[IntegerQ[p],
> If[p==0, 1, Floor[N[Log[2, Abs[p]]/Log[2, 10]]]+If[p>0, 1,
> 2]],
> If[Head[p]===Rational,
> SimplifyCount[Numerator[p]]+SimplifyCount[Denominator[p]]+1,
> If[Head[p]===Complex,
> SimplifyCount[Re[p]]+SimplifyCount[Im[p]]+1,
> If[NumberQ[p], 2,
> SimplifyCount[Head[p]]+If[Length[p]==0, 0,
> Plus@@(SimplifyCount/@(List@@p))]]]]]]
>
> Would it be helpful to have this in the Documentation?
It would be more helpful if it were more readable, that's for sure.
I think Adam's function is equivalent to
SimplifyCount[0]=1
SimplifyCount[_Symbol]:=1
SimplifyCount[p_Integer]:= Floor[N[Log[2, Abs[p]]/Log[2, 10]]]+If[p>0, 1, 2]
SimplifyCount[p_Rational]:=
SimplifyCount[Numerator[p]]+SimplifyCount[Denominator[p]]+1,
SimplifyCount[p_Complex]:= SimplifyCount[Re[p]]+SimplifyCount[Im[p]]+1,
SimplifyCount[p_?NumberQ]:= 2
SimplifyCount[p_] := Plus@@(SimplifyCount/@(Append[List@@p,Head[p]]))
(*everything else*)
not tested, but you get the idea. Adam's program may be faster in some
way, or he may have written because he thinks in terms of If[Head[]==]
and it did not occur to him to use pattern matching. Or maybe my program
doesn't work because the interactions of the multiple patterns cause
problems -- I require that the patterns be applied in the right order
and Mathematica may be randomizing them in some way. (That is, 0 is an
Integer, but we want to use the first line, not the 3rd).
One way to make documentation readable is to have a system that is
logically consistent --- the semantics are simpler. By this measure, it
would be much easier to understand the system and read this
documentation if the pattern matching for p/q and r+s*I did not need
special cases when p and q , or s were numbers, but just
looked like the same patterns as the cases when p,q, s are symbols.
Then the complexity function would look like this
SimplifyCount[0]=1
SimplifyCount[_Symbol]:=1
SimplifyCount[p_Integer]:= Floor[N[Log[2,Abs[p]]/Log[2,10]]]+If[p>0,1,2]
SimplifyCount[p_?NumberQ]:= 2
SimplifyCount[p_] := Plus@@(SimplifyCount/@(Append[List@@p,Head[p]]))
5 lines, not 11. [In fact, it may be that this documentation would be
worth providing if it were noted that this is a "simplification" of how
it really works.]
RJF
Prev by Date:
**Re: I->-I, my solution. See examples at the end. Improvements/ suggestions/**
Next by Date:
**Re: inequality as constraints on NDSolve +Integral...**
Previous by thread:
**Re: Re: Re: Re: Radicals simplify**
Next by thread:
**Re: Radicals simplify**
| |