1. Re: abs function
Message text written by Nick:
>These are the algorithms I use for abs (and sgn, another function I find=
>useful). They work for sequences as well as atoms. I don't expect it's
>the fastest solution but should certainly be faster than invoking sqrt,
>as was suggested earlier.
>
>function sgn(object r)
> return (r > 0) - (r < 0)
>end function
>
>function abs(object r)
> return r * sgn(r)
>end function
Your sgn function (also suggested by LLH and others) seems to be about th=
e
fastest way to do a general object. Here is a faster abs function (but n=
ot
as terse as yours). Maybe someone can come up with an even faster abs or=
sgn function for a general object?
Colin Taylor
--start code
function abs(object obj)
object val
if atom(obj) then
if obj < 0 then
obj =3D -obj
end if
else
for i =3D 1 to length(obj) do
val =3D obj[i]
if sequence(val) then
obj[i] =3D abs(val)
else
if val < 0 then
obj[i] =3D -val
end if
end if
end for
end if
return obj
end function
-- end code
