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MaplePrimes Activity

These are questions asked by sand15


I would like to determine if some lengthy expression F is linear in one of its inderteminates X.
 I use to use type(F, linear(X)) to do this but I've just found that if F is piiecewise defined, then type(F, linear(X)) returns false even if E is linear in X...
For instance, let  F := a*X+piecewise(Y<0, X, b)
then type(F, X) returns false.

I do not pretend it is a bug: at first sight I would say that F is linear with respect to X but maybe the notion of linearity with respect to an indeterlinate must be interpretated as "linear on each branch" ?

For the moment I've circumvented the problem by doing this :
dF := diff(F, X):
has(dF, X):
# returns {\emptyset} if F is linear in X

But, as I said, F can be a rather lengthy expression invoking a lot of piecewise constructors, and I don't think that computing dF is an efficient way to do the job.

Do you have a better idea to proceed?

Thanks in advance


I discovered that the option legend, when used in plots:-inequal, returns an empty graphic.
Is it a bug or a deliberate choice?

Anyways, is it possible to insert a legend in a simple way (that is without using textplot for instance)?



Let's take the last example (Maple 2019) given in help[sparsematrixplot] (representation of the adjacency matrix of a graph).
Vertices of this graph are labelled 1, 2, ...20.
Suppose I change these names as a, b, ...t.
I would like the tickmarks of the sparsematrixplot output match the names of the vertices of the graph, and not the integers 1, 2, ..20

I tried this:
S := [$1..20] =~ StringTools:-Char~(96 +~  [$1..20]);
plots:-sparsematrixplot(..., tickmarks=[S, S])

But the only the tickmars of the columns are changed, not those of the rows.

Is it possible to change the names of the tickmarks ?

Thanks in advance.


Defining variables named H2 or O2 doesn't pose any problem (H__2 for instance), but could it be possible in Maple 2019 to define a variable named H2O2 ?

Thanks in advance


I have a set of functions of the form P :=  { a(t), b(t), f(g(t)), u(v(w(t)), A(a(t), b(t)), ... } and I want to obtain the set Q := { a(t), b(t), g(t), w(t) } (that is the set of the innermost functions)
Since more than an hour I'm fighting without success with select and parmatch and I'm desperatly askink for your help.

Thanks in advance
PS : the list P only contains functions of t, never of t and of another variables.

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