Preben Alsholm

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15 years, 254 days

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These are Posts that have been published by Preben Alsholm

It would be nice if Maple had a procedure which could turn a procedurelist into a listprocedure.
I use these words in the sense they are used in dsolve/numeric.
Thus by a procedurelist I mean a procedure returning lists (of numbers).
By a listprocedure I mean a list of procedures all having the same formal parameters and each returning one number.
Thus a `convert/listprocedure`should accept a procedurelist p as input and give as output the corresponding listprocedure [p1,p2, ... pN] where N is the number of elements in the output from p.

I tried making a `convert/listprocedure` myself and in doing so found that it was not totally trivial.
I had lots of problems but did end up with something that seems to work.

convert-listprocedur.mw

But my main point is that Maple ought to have some such facility either as described available to the user or by changing fsolve, complexplot or what have you, so that procedurelists are accepted.

Is there a way to get told only once that  "There are new updates on www.mapleprimes.com that match your notification subscriptions:" ?

I always receive 3 (when I do get any), and yes, they are identical.

3 times is better than 0 times, though.

In examining ODE models containing parameters I don't like to assign values to these, but use the form

param:={a=2, b=7};
and then
eval(expression, param);

This works well. There are situations, however, where this method can be cumbersome.
This would be the case in a situation like this:

plot(a*sin(x),x=0..b);

You could do

plot(op(eval([a*sin(x),x=0..b],param)));

But maybe an operator having a syntax similar to 'assuming' could be useful.

How is it possible to get the following error message

Error, invalid input: DMat:-DSolveSys expects default value for keyword parameter begynd to be of type Vector, but received {}

?

I thought that the default value of a keyword parameter need not match any particular type, in fact so it says in the help page for 'Procedure Parameter Declarations' :

There is quite a difference in the way plot and plots:-pointplot handles colors when using lists of HSV or HUE values.

In the first example below the colors are quite different when using plot and pointplot with HSV.

In the second example plot handles HUE values, but pointplot reports an error.

#First HSV

plot([k$k=0..4],0..1,color=[seq(COLOR(HSV,k/4,1,1),k=0..4)],thickness=50,axes=none);
plots:-pointplot([[k,k]$k=0..4],symbolsize=100,symbol=solidcircle,color=[seq(COLOR(HSV,k/4,1,1),k=0..4)],axes=none);

#Now HUE.

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