1. freeof is the way it is so it can be used in pattern matching
as in declare(a,freeof(x)). I suppose you could change the
conventions for calls to predicates for pattern matching, but
unless you do so, you better leave freeof in there.
2. Deprecating functions in maxima seems to be essentially
impossible. All one can do is leave out a feature from
your version of the documentation, I think.
3. Checking a rat form to see if it depends on a variable
is complicated. An expression could be a rational polynomial
in x, y, sin(x). But it might happen to have simplified
so that it is 0*x+0*sin(x)+0*y+45.
4. I'm not sure what your intent is (0r if you've said
it right). Do you intend to look "syntactically" in the
expression tree to see if there is an occurrence of x
and say it is there?
Maybe you could use another word different from nfree, like
independent or syntacticallyfree or ??
RJF
Dan Stanger wrote:
> I am going to write a replacement for freeof.
> For reference following is the original definition:
> Function: FREEOF (x1, x2, ..., exp)
> yields TRUE if the xi do not occur in exp and FALSE otherwise. The
> xi are atoms or they may be subscripted names,
> functions (e.g. SIN(X) ), or operators enclosed in "s. If 'var' is a
> "dummy variable" of 'exp', then FREEOF(var,exp); will
> return TRUE. "Dummy variables" are mathematical things like the
> index of a sum or product, the limit variable, and the
> definite integration variable. Example: FREEOF(I,'SUM(F(I),I,0,N));
> returns TRUE. Do EXAMPLE(FREEOF); for more
> examples.
>
> My replacement NFREEOF is defined as follows:
> NFREEOF(exp, x1,x2...) or NFREEOF(exp,list).
> Currently, FREEOF converts each of its arguments to general form.
> For now, I am going to check if the xi or the elements of the list are
> in rat form and convert them then,
> a improvment will be to to the check without the conversion.
> I would also like to deprecate FREEOF.
> Comments?
> Dan Stanger
>
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