MaplePrimes Posts

MaplePrimes Posts are for sharing your experiences, techniques and opinions about Maple, MapleSim and related products, as well as general interests in math and computing.

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  • The ongoing spam problem has made this site unusable. Even after spam is removed, it's effect on the "recent" pages persists. This is a months-old problem.

    And after over a year the site still has no good support for displaying mathematics, or for entering 2D Maple input.

    And there is no indication of any clear and concrete plan to properly address either of these problems, despite repeated requests and inquiries by members.

    Hello:

    I'm studying many time ago the quantum chemistry of rectivity . so far, I can arrive to news theories from my experince on Maple productcs as they are incorporated in my theoric equations. I have glad  on communicat my previous results on Chemical Reactivity and Uniffied Field. botn of those ara closely related and my purpose is obtain diffusion and comments on these.

    - My first paper was on Chemical Reactivity (Kinetics and Dynamics) and...

     

    Here is the progress made in the investigation of what I call the convergents constants:
    https://oeis.org/wiki/Table_of_convergents_constants

    I wonder if anyone would be interested in adding anything to it. I would like to see the convergents constants studied some in Maple to compare with my Mathematica results; my investigation is in dire need of some proof other than my...

    A problem with convert,StandardFunctions

     

    P := hypergeom([-k,1/2-k],[-2*k],1-z^2);

    (1)

    convert(P,StandardFunctions);
    P1a:=subs(k=1,%);

     

    (2)

    P1:=subs(k=1,P);

    (3)

    plot({P1,P1a},z=-1..1,0..2);

     

    convert(P,StandardFunctions) assuming k::posint;

    (4)

     

     

    Download hyp.mw

     

    Most of the time I don't know what or why things are happening here on the mapleprimes site. 

    I don't want it as a post or question as it gets shuffled down and is useless later on anyway. 

    I would like a news section to inform me and everyone else of what is currently being worked on (ie the site programmers are currently working on ....  currently tags for posts are being updated), what is currently happening (spam attack - although this seems to be on the upswing lately...

    Hello all,

    I've noticed that something has changed to the type of sqrt in Maple 15, which breaks backward compatibility...

    In Maple 14, we have

    > type(sqrt,procedure);          true
    > type(sqrt,`module`); false
    > eval(sqrt);          proc(x::algebraic, f::identical(symbolic))  ...  end proc

    while in Maple 15, we have

    > type(sqrt,procedure);          false
    > type(sqrt,`module`); true

    Following Christopher2222 request, I wrote the following procedures for "exact" cubic Hermite spline interpolation,

    p:=proc(x0,p0,m0,x1,p1,m1,x)
    local t,d;
    d:=x1-x0;
    t:=(x-x0)/d;
    p0+(d*m0+(3*(p1-p0)-d*(2*m0+m1)+(2*(p0-p1)+d*(m0+m1))*t)*t)*t
    end:
    
    pb:=proc(x0,p0,x1,p1,m1,x)
    local t,d;
    d:=x1-x0;
    t:=(x-x0)/d;
    p0+(2*(p1-p0)-d*m1+(p0-p1+d*m1)*t)*t
    end:
    
    pe:=proc(x0,p0,m0,x1,p1,x...

    This is for Spanish speakers only. Not related to Maple, but related to Math. The Spanish newspaper El Pais has a series of videos on various math problems, together with solutions (posted later), it's set up as a sort of competition but just watching is (usually) great fun. You can access the full archive online.

    You probably don't need to know much Spanish to follow the problems. Much is illustrated in writing on a black or white board. If you don't speak any Spanish...

    Comments to the answers are not counted as replies in the list of recent posts, and adding a comment to an answer doesn't move the question up. 

    Only answers and comments to the question are counted and adding them leads to moving the question up.

    Although the source is very old (Maple 6) the topic is interesting.  Should one come across the webpage Analysis and Synthesis of digital sound samples with Maple 6 located here http://www.maplesoft.com/applications/view.aspx?SID=3940&view=html they may have a dissapointing maple browsing experience when 3 of the links they try to access are broken and not available.  

    After Poker's Black Friday (April 15), I started to think about moving to Canada, and I realized that I know very little about our northern neighbor.

    I would appreciate any suggestions about a nice place with not very expensive rent (for a handicapped accessible house), safe for living, with a (very) good Internet connection, not very far from shopping places (do you have Walmarts?) etc.

    Being close (in, say, 50 miles or less) to a casino with a poker room is desirable, but not absolutely necessary.

    Thank you,
    Alec

       The Kolmogorov-Smirnov test is a widespread, simple, and effective test to check the hypotheses of the form H[0]:=F[ksi](x)=F(x), where a function F[ksi](x) is the CDF of a population distribution, a function F(x) is a given continuous function (the Kolmogorov  test), and the hypotheses of the form  H[0]:=F[1](x)=F[2](x), where F[j](x), j=1,2, are the CDF of two population distributions, both are assumed to be continuous (the Smirnov test).  See the ...

    A Plot Component (on the right below) can act as a kind of 2-dimensional "slider" for inputing values of two parameters at once.

    The polar plot (on the left below) makes use of both values.

    If you click in the right Plot, and drag around the mouse cursor for a while, then the left Plot will be continuously updated.

    Make sure to execute the collapsed code-edit region, to initialize it. (Just click on it, to execute. Or expand, look, and right-click on it.)

     

     

     

    Click any point above, & Drag

     

    Download plotslider1.mw

     

    This is in response to a Question about the speed and memory use of an animated DEplot. The problems are that the example's animation was slow to create, and prohibitively expensive to save in a Document.

    An alternative approach is to combine multiple calls to plots:-odeplot with a call to plots:-fieldplot to supply the background flow arrows. This is a lot faster. It takes less memory to create and run, but the GUI may still consume too much resources saving it. The good news is that it's so much faster that it's not inconvenient to re-run the entire thing from scratch. And so it's quite feasible to remove all the expensive output from the Document prior to saving and thus avoid the whole resources problem.

    The original questioner also wanted to visualize with resect to two varying parameters. So I've also done an implementation of that using Embedded Components and two Sliders.

    Here is the old DEplot animation. It takes about 40 sec to create it animation on an Intel i7.

    Here is the new combined odeplot+fieldplot animation. It takes a second or two to create its animation on an Intel i7.

    Here is the DEplot in Embedded Components. It's very slow, and the image doesn't change smoothly with the sliders.

    Here is the new combined odeplot+fieldplot in Embedded Components. Its image changes pretty smoothly with the sliders.

    I encourage completely quitting the GUI (not just restart, or close Document and re-Open) between comparison runs of these implementations, of you want to get a really good feel for the effects of both running them as well as saving them (with and without all output).

    For the Embedded Component documents, the functioning code resides inside the "initialize" button. (right-click, go to Component Properties, Action When Clicked, only if you want to inspect it.) To run those two  Documents, execute all the commands (use the triple-exclam from the menubar if you like), and then press the "initialize" button, and then move the sliders.

    The difference in performance is related partly to the use of hardware datatype Arrays in the PLOT structures generated by odeplot and fieldplot. (But an `arrow` primitive would help even more!)

    And (I think) there is improvement by virtue of using dsolve/numeric/parameters in the use of `odeplot`. That saves overhead from repeated cold invocations of dsolve/numeric. And DEplot doesn't support that, since it expects as argument the system of DEs and ICs. The newer `odeplot` command accepts the procedure returned by dsolve/numeric, and thus allows for efficient repeated setting of parameter values. The `fieldplot` command doesn't need the solution of the DE system at all: it just needs the DEs.

    I would have considered wrapping the whole combined approach up into a single command, but it might have to accept separate options for the view ranges, in order to always look its best. A smart version might be able to deduce the computed ranges from the odeplot output, and then create the background fieldplot based on that.

    I've made a little progress in definig a new set of constants from the generalized continued fraction that I mentioned in my previos post.

     

    See https://oeis.org/wiki/Convergents_constant.

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