On Oct. 20, Stavros Makrakis wrote:
> Something like this?:
>
> declare(union,nary)$
> listofops(expr) := block([inflag:true], if mapatom(expr) then {} else
> adjoin(op(expr),xreduce(union,maplist(listofops,expr))))$
>
> inflag:true uses the internal form for efficiency; be aware that
> listofops(-a/b) => {"*","^"} (from (-1)*a*b^(-1)) instead of {"-","/"}
>
Actually, I asked for the wrong thing. I should have asked for
something to detect the presence, in an expression, of one
of Maxima's special functions (true/false).
I found funp, funp1, funp2 in ...share/fourie.mac, which does
the job to define spfunp (expr) ; see below:
-----------------------------------------
(%i1) load(temp);
(%o1) c:/work2/temp.mac
(%i2) spfunp (bessel_y(2,x));
(%o2) true
(%i3) spfunp (x);
(%o3) false
(%i4) spfunp (x*bessel_y(2,x) + bessel_j(0,x));
(%o4) true
--------------------------------------------------
/* temp.mac
oct. 20, 2011
code spfunp to detect special functions:
return true is any are found
return false otherwise
*/
/* funp1: code from ....share/calculus/fourie.mac */
funp1(fun,exp):=block([inflag],inflag:true,
if mapatom(exp) then false
else (if inpart(exp,0) = fun then true
else member(true,maplist(lambda([q],funp1(fun,q)),exp))))$
spfunp (expr) :=
block ([spfun, spf:false],
for spfun in
[bessel_j,bessel_y,bessel_i,bessel_k,
hankel_1,hankel_2,struve_h,struve_l,
assoc_legendre_p,assoc_legendre_q,
%f,gamma,gammagreek,gammaincomplete,
hypergeometric,slommel,%m,%w,erfc,
expintegral_e,expintegral_e1,
expintegral_ei,expintegral_li,
expintegral_si,expintegral_ci,
expintegral_shi,expintegral_chi,
kelliptic,parabolic_cylinder_d] do
if funp1 (spfun,expr) then (
spf:true,
return()),
spf)$
-------------------------------------------------