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 following three commands 

    plots:-implicitplot(3*cos(x) = tan(y)^3, x = -Pi .. Pi, y = -(1/2)*Pi-1 .. (1/2)*Pi+1, thickness = 3, crossingrefine = 1, rational = true, signchange = true, resolution = 1000, gridrefine = 2);
    plots:-implicitplot(3*cos(x) = tan(y)^3, x = -Pi .. Pi, y = -(1/2)*Pi-1 .. (1/2)*Pi+1, thickness = 3, crossingrefine = 1, rational = true, signchange = false, resolution = 1000, gridrefine = 2);
    plots:-implicitplot(3*cos(x) = tan(y)^3, x = -Pi .. Pi, y = -(1/2)*Pi-1 .. (1/2)*Pi+1, thickness = 3, crossingrefine = 1, rational = true, resolution = 1000, gridrefine = 2);

    produce the same incorrect plot 

    It is clear the sraight lines given by y=Pi/2 and y=-Pi/2 are superfluous. It should be noticed that the Mmma's ContourPlot command without any options produces a correct plot.

    Up to http://www.maplesoft.com/support/help/Maple/view.aspx?path=solve&term=solve

    • 

    If the solve command does not find any solutions, then if the second argument is a name or set of names, then the empty sequence (NULL) is returned; if the second argument is a list, then the empty list is returned. This means that there are no solutions, or the solve command cannot find the solutions. In the second case, a warning is issued, and the global variable_SolutionsMayBeLost is set to true.

     Let us consider 

    solve({x > -Pi, (tan(x)-tan(x)^2)^2-cos(x+4*tan(x)) = -1, x < Pi}, [x]);
                                   []
    

    We see the command omits the solution x=0 without any warning. It should be noticed that Mathematica solves it, outputting

    {{x -> 0}, {x -> 0}}

    and the warning

    Solve::incs: Warning: Solve was unable to prove that the solution set found is complete.

    One may draw a conclusion on her/his own.

     

    From October 19-21, the third installment of the Maple T.A. and Möbius User Summit took place. Making the move back to Europe this year, the three-day conference was held at the beautiful Vienna University of Technology in the heart of Vienna, Austria. The scope of this year’s event expanded to include Maplesoft’s newest product, Möbius, an online courseware environment, which is designed to help academic institutions move their STEM courses online.

    This year’s Summit brought together participants from 20 countries, including Australia, the Czech Republic, Poland, China, Norway, India, Egypt, Japan, the Netherlands, and many others. Needless to say, there is great interest in learning more about how Maple T.A. and Möbius can play a role in shaping the educational landscape.

    Video recordings of each presentation will be made public soon, so keep an eye out for them!

    Conference attendees take in the sights on the veranda at TU Wien

    Getting Down to Business

    Presentations were divided into 5 overarching themes as they relate to Maple T.A. and Möbius: Shaping Curriculum; Content Creation; Experiences Using Möbius; Integrating with your Technology; and The Future of Online Education. Presentations were given by representatives from schools across Europe, including DTU (Denmark), TH Köln (Germany), Imperial College of London and University of Birmingham (UK), Vienna UT (Austria), KTH Royal Institute of Technology (Sweden), Université de Lausanne (Switzerland), and others.

    Many talks showcased the impressive versatility of Maple T.A. as a online assessment system, and Möbius to have practical applications in all STEM subjects, from Nuclear Engineering to Operations Management and many subjects in between.

    Perhaps the discussion that gave Maplesoft the most feedback was led by Steve Furino from the University of Waterloo, who divided attendees up into groups to formulate a wish list of what they’d like to see in a courseware authoring environment. The list had over 40 items.


    Linda Simonsen, Country Manager in the Nordic, records a group’s wish list

    Notable Quotables

    Many thought-provoking statements and questions were posed, but the following few stood out above the rest:

    • “Wouldn’t it be wonderful if you could take the best course from the best instructor anywhere in the world?”
    • “With Maple T.A., we can divert resources away from grading and over to tutoring.”
    • “Möbius rescued us!”

    Get the party started!

    While each day was full of invigorating conference discussions, evenings provided ample opportunity to ditch the suit jacket and tie, and enjoy the lively Austrian atmosphere. The first evening at the Zwölf Apostelkeller was the perfect venue to break the ice while satisfying those taste buds longing for some traditional Viennese cuisine. Once Schnitzel, Käsespätzle (a delicious German version of Mac and Cheese), Strudel, Kaiserschmarren (shredded pancake), and a glass or two of wine hit the table, people soon forgot about the pouring rain outside.

    The evening reception took place 3-4 levels under ground

    Michael Pisapia, VP of Europe, serves digestifs to guests

    It would have been hard to top the social in the Apostelkeller, but the next evening sure tried.

    Day 2 finished with an impressive formal dining experience at the historic Gerstner Beletage in the Palace Todesco, built in 1864 and situated directly across from the Vienna State Opera House. The 500-room palace was home to Eduard Freiherr von Todesco, a well-known Viennese banker.

    View from the palace of the Vienna State Opera House

    Jonny Zivku, Maple T.A. Product Manager, gives opening remarks at the Gerstner Beletage im Palais Todesco

    Jonathan Watkins from the University of Birmingham and Michael Pisapia - both dressed to impress

    The skies finally cleared enough to take some photos, but only after most people had gone home. Thankfully Aron Pasieka, Möbius Project Manager, was still around to get some great shots of the city. Enjoy!


    Before the skies cleared vs. after the skies cleared

    From beginning to end, the entire Summit was very well received by everyone who attended.

    We would be remiss if we did not thank our incredible hosts at the Vienna University of Technology. Stefanie Winkler, Professor Andreas Körner, and Professor Felix Breitenecker were beyond helpful in bringing many of the finer details together, as well as helping many people overcome the language barrier.

    We can’t wait to do it all again in London, England in 2017, and hope to see just as many new faces as familiar ones.

     

    Photo credits: A. Pasieka, A. French, H. Zunic, J. Cooper

     

    Update: The conference presentation recordings are now available here on our website.

    Just a simple graphical view of Maple releases over the years.

    with(plots):
    MapleVersions := [[1, 1982], [1.1, 1982.05], [2, 1982.33], [2.1, 1982.42], [2.15, 1982.58], [2.2, 1982.92], [3, 1983.17], [3.1, 1983.75], [3.2, 1984.25], [3.3, 1985.17], [4, 1986.25], [4.1, 1987.33], [4.2, 1987.92], [4.3, 1989.17], [5.1, 1990.58], [5.2, 1992.83], [5.3, 1994.17], [5.4, 1996], [5.5, 1997.83], [6, 1999.92], [7, 2001.5], [8, 2002.25], [9, 2003.42], [9.5, 2004.25], [10, 2005.33], [10.01, 2005.58], [10.02, 2005.83], [10.03, 2006.17], [10.04, 2006.42], [10.05, 2006.5], [10.06, 2006.75], [11, 2007.08], [11.01, 2007.5], [11.02, 2007.83], [12, 2008.33], [12.01, 2008.75], [12.02, 2008.92], [13, 2009.25], [13.01, 2009.5], [13.02, 2009.75], [14, 2010.25], [14.01, 2010.75], [15, 2011.25], [15.01, 2011.42], [16, 2012.17], [16.01, 2012.33], [17, 2013.17], [17.01, 2013.5], [18, 2014.17], [18.01, 2014.33], [18.015, 2014.5], [18.02, 2014.83], [19, 2015.17], [19.1, 2015.33], [20, 2016.17], [20.1, 2016.25], [20.15, 2016.30]]
    a:=map(ListTools:-Reverse,MapleVersions): #swap x-y axis
    plot(a, style = point, symbol = point)
    

    This MaplePrimes guest blog post is from Ian VanderBurgh, the Director of the Center for Education in Mathematics and Computing (CEMC) and a Lecturer in the Faculty of Mathematics at the University of Waterloo. He has been overseeing a project to develop online, interactive mathematics curriculum for high school students, and has been integral in the development of Möbius, Maplesoft's online courseware environment.

    Start with one part interest in online education, add one part increased functionality for developing online content, and mix with one part increased focus in the media and elsewhere on mathematics education.  What does this produce?  The perfect time to create high-quality online resources to support learning and teaching in mathematics.

    The Centre for Education in Mathematics and Computing (CEMC) at the University of Waterloo aims to increase interest, enjoyment, confidence, and ability in mathematics and computer science among learners and educators in Canada and internationally.  For more than fifty years, we have been working with teachers to support the important work that they do in the classroom.  When online courses rose to prominence several years ago, we felt that this gave us the perfect opportunity to create materials to better support the curriculum being taught across Canada and around the world.

    The content for what we now call “Phase One” was planned: Advanced Functions (Pre-Calculus) as well as Calculus & Vectors.  These materials would support the education of students in their final year of secondary school, and also provide materials to reinforce concepts for students in STEM programs at the post-secondary level.

    After deciding on the content, we needed a platform.  We knew that we needed one with exceptional mathematical capabilities.  Thus, we have been working hand-in-hand with Maplesoft ever since.

    With content and platform established, the style began to take shape.  It is based around what one of my colleagues calls “the five Es”: Exposition (onscreen text with synchronized audio), Experimentation (worksheets where users can manipulate mathematical objects), Evaluation (re-generating quiz questions), Exercises (with answers and solutions), and Enrichment (application and extension problems and solutions).  Have a look at the materials and watch a video about the courseware.  After less than two years of “public life”, Phase One has received more than 2 million page views and usage is accelerating.

    But why stop there?  Through the development of Phase One, all of the stakeholders realized that, while what we created was great, we needed better and more efficient development tools.  Thus, Möbius was born.  (In the meantime, the CEMC separately launched Phase Two of this ambitious initiative: resources in computer science to support the teaching and learning of programming concepts.)

    Now, using the full capabilities of Möbius, we are developing Phase Three, a parallel set of resources to Phase One that will support mathematics at the Grade 7/8 level.  Why Grade 7/8?  We believe that these are very important years in education, that it is vital to future success in STEM disciplines that students flourish in these years, and that we should do whatever we can to support this.

    What comes next?  Time will tell.  But, the CEMC will be there supporting mathematics and STEM education.  STEM disciplines will drive almost everything in the twenty-first century, and we have an obligation to do whatever we can to give young people every possible chance for success.

    As mentioned a few weeks back, we have been working on an update to MaplePrimes designed to dramatically curtail the amount of spam we have been receiving. I'm happy to say that we implemented these features earlier today, and in the hour or so since publication, they have already helped prevent multiple messages from being posted.

    Using content posted to MaplePrimes over the past few months as a baseline, this new feature is successfully able to detect 90% of spam, while maintaining a false positive (i.e., incorrectly identifying a legitimate question or post) rate of 1%.

    If a message is detected as spam, it is immediately quarantined and not publicly posted. Importantly, any user who posts a message seen as spam is immediately informed, and is provided with a simple mechanism to let us know so that their post can be reinstated (if it is in fact legimate.)

    We will be closely monitoring these services to ensure that they are working as intended. In the meantime, I am very hopeful that they help improve the experience for our members, and require much less effort from our dedicated group of spam fighters.

    Hi Mapleprimes,

    I have made this little procedure with Maple. 

    check_g_conjecture_10.pdf

    similar to this next one check_g_conjecture_10.mw

    This may be worth a look.

    Regards,

    Matthew

    P.S.   see  https://en.wikipedia.org/wiki/Goldbach%27s_conjecture

    In My Humble Opinion, Wikipedia is a good crowd sourced resource.

     

    The content in all comments posted on any Blog posts are missing.  What happened to them?

    Below I have pasted the recent post of a spammer who's title was http:// 

    First of all, I thought those spam filters had taken care of those. 
    Secondly why isn't there an http:// with a zero rating user poster filter on this forum yet?

     

     

    When I made the suggestions about new ways to delete spam, I specifically requested that there be no confirmation dialogs. I even emphasized it. But I see that there is such a dialog. Was the author of the spam asked to confirm whether they wanted to make the post? So you're saying that my time is worth less than the spammer's. Every time that I need to answer that dialog, it's an insult, a slap in the face direct from Maplesoft.

    The new look and feel of MaplePrimes is ugly and disfunctional nearly beyond belief. Please put back the old look and feel ASAP. I am not commenting here about any new controls or features because I haven't tried them yet. The wasting of space on the screen is incredible. The windows with sharp corners are ugly. The grey colors make it look like selections are inactivated. Most of the controls that can be clicked on are not highlighted in any way.

    Just as an example of the waste of space, I now need to scroll down three screens just to get to the Active Conversations stack.

    Once again, anything that you can do to make the look and feel similar to any StackExchange forum would be an improvement.

    Today we have published an update to MaplePrimes that includes a variety of improvements. Many of these changes are a direct result of member feedback and suggestions, and I am very appreciative for that!

    What follows is a brief summary of the changes. As always, we remain very interested in your thoughts and feedback, and look forward to your further suggestions.

    Also, a note that, as mentioned in a previous post, we have already begun working on a further update to address the influx of spam we have been receiving. This update will be published within the next 2-3 weeks.

    Updated Look and feel
    The most obvious change is the updated interface. With a few exceptions, the previous layout and functionality has been maintained, but with a cleaner, more responsive, and more appealing look.

    New message editor
    This update includes a new text editor called CKEditor. This editor provides a simpler, cleaner experience for posting your messages and also aligns MaplePrimes more closely with the Maplesoft product suite.

    Notifications
    You will notice a new flag icon in the upper right hand corner of the interface. This is the new MaplePrimes Notification feature, and it provides similar functionality to what we have become accustomed to on other social media sites. The icon is displayed in an orange color when you have notifications, and then when opened, your new notifications are highlighted in blue. Clicking on a notification will take you directly to the item being referenced.

    Improved flow for removing spam messages
    As any MaplePrimes moderator could tell you, removing spam on MaplePrimes was a cumbersome process taking 4 clicks. In this update, this process has been streamlined to 2 clicks, which will make the process considerably faster for our legion of spam fighters. In addition, the ability to remove spam is now available on all message types – comments, replies, etc.

    Identification Badges
    There are now 3 identification badges that are used throughout MaplePrimes wherever member information is displayed. These include:

     Denotes a member who works at Maplesoft

     Site moderators are the heart and soul of MaplePrimes, and are now identified by this new badge

     A member who also particpates in the Maple Ambassador Program

    Other fixes and improvements
    In addition to the changes mentioned above, several other minor fixes and improvements were made.

    This post - this is a generalization of the question from  here .
    Suppose we have  m  divisible objects that need to be divided equally between n persons, and so that the total number of parts (called  N  in the text of the procedure) after cutting should be a minimum. Cutting procedure exactly solves this problem. It can be proved that the estimate holds  n<=N<=n+m-1, and  N<n+m-1 if and only if there are several objects (< m), whose measures sum to be a multiple of the share (Obj in the text of the procedure).

    In the attached file you can find also the text of the second procedure Cutting1, which is approximately solves the problem. The procedure Cutting1 is much faster than Cutting. But the results of their work are usually the same or Cutting procedure gives a slightly better result than Cutting1.

    Required parameters of the procedure: L is the list of the measures of the objects to be cutted, n is the number of persons. The optional parameter  Name is a name or the list of names of the objects of L (if the latter then should be nops(L)=nops(Name) ).

     

    Cutting:=proc(L::list(numeric), n::posint, Name::{name,list(name)}:=Object)

    local m, n1, L1, L11, mes, Obj, It, M, N;

    uses combinat, ListTools;

    m:=nops(L); L1:=sort([seq([`if`(Name::name,Name||i,Name[i]),L[i]], i=1..m)], (a,b)->a[2]<=b[2]);

    mes:=table(map(t->t[1]=t[2],L1));

    Obj:=`+`(L[])/n;

    It:=proc(L1, n)

    local i, M, m1, S, n0, a, L2;

    if nops(L1)=1 then return [[[L1[1,1],Obj]] $ n] fi;

    if n=1 then return [L1] fi;

    for i from 1 while `+`(seq(L1[k,2],k=1..i))<=Obj do

    od;

    M:=[seq(choose(L1,k)[], k=1..ceil(nops(L1)/2))];

    S:=[];

    for m1 in M while nops(S)=0 do n0:=`+`(seq(m1[k,2],k=1..nops(m1)))/Obj;

    if type(n0,integer) then S:=m1 fi;

    od;

    if nops(S)=0 then

    a:=Obj-`+`(seq(L1[k,2],k=1..i-1));

    L2:=[[L1[i,1],L1[i,2]-a],seq(L1[k],k=i+1..nops(L1))];

     [[seq(L1[k], k=1..i-1),`if`(a=0,NULL,[L1[i,1],a])],It(L2,n-1)[]] else L2:=sort(convert(convert(L1,set) minus convert(S,set), list),(a,b)->a[2]<=b[2]);

    [It(S,n0)[], It(L2,n-n0)[]] fi;

    end proc;

    M:=It(L1,n);

    N:=add(nops(M[i]), i=1 ..nops(M));

    Flatten(M, 1);

    [Categorize((a,b)->a[1]=b[1],%)];

    print(``);

    print(cat(`Cutting scheme (total  `, N, `  parts):`) );

    print(map(t->[seq(t[k,2]/`+`(seq(t[k,2],k=1..nops(t)))*t[1,1],k=1..nops(t))], %)[]);

    print(``);

    print(`Scheme of sharing out:`);

    seq([Person||k,`+`(seq(M[k,i,2]/mes[M[k,i,1]]*M[k,i,1], i=1..nops(M[k])))],k=1..n);

    end proc:

     

    Examples of use.

    First example from the link above:

    Cutting([225,400,625], 4, Cake);  # 3 cakes must be equally divided by 4 persons

    eval(%,[Cake1,Cake2,Cake3]=~[225,400,625]);  # Check

              

     

     

     

    Second example (the same for 10 persons):

    Cutting([225,400,625], 10, Cake);

            

     

     

    Third example (7 identical apples should be divided between 12 persons):

    Cutting([1 $ 7], 12, apple); 

     

     

    Cutting.mw

     

     Edited:

    1. Fixed a bug in the procedure Cutting  (I forgot sort the list  L2  in sub-procedure  It  if  nops(S)<>0 ).

    2. Changes made to the sub-procedure  It  for the case if there are several objects (>1  and  < m), whose measures                     sum to be a multiple of the share  Obj .

     

    The 196 algorithm goes like this.  Start with an integer.  Reverse the digits.  Add the reversed number to the integer.  For most numbers, this eventually leads to a palendrome.  That is to say the number is equal to the reversed number.  I wrote a little Maple procedure to explore 196, the smallest number that will probrably never become a palendrome when put into the algorithm.

     

    Let me know if you like my code.

    Regards,
    Matt

    proc4.pdf

    proc4.mw

    http://mathworld.wolfram.com/196-Algorithm.html

     

    The material below was presented in the "Semantic Representation of Mathematical Knowledge Workshop", February 3-5, 2016 at the Fields Institute, University of Toronto. It shows the approach I used for “digitizing mathematical knowledge" regarding Differential Equations, Special Functions and Solutions to Einstein's equations. While for these areas using databases of information helps (for example textbooks frequently contain these sort of databases), these are areas that, at the same time, are very suitable for using algorithmic mathematical approaches, that result in much richer mathematics than what can be hard-coded into a database. The material also focuses on an interesting cherry-picked collection of Maple functionality, that I think is beautiful, not well know, and seldom focused inter-related as here.

     

     

    Digitizing of special functions,

    differential equations,

    and solutions to Einstein’s equations

    within a computer algebra system

     

    Edgardo S. Cheb-Terrab

    Physics, Differential Equations and Mathematical Functions, Maplesoft

    Editor, Computer Physics Communications

     

     

    Digitizing (old paradigm)

     

    • 

    Big amounts of knowledge available to everybody in local machines or through the internet

    • 

    Take advantage of basic computer functionality, like searching and editing

     

     

    Digitizing (new paradigm)

    • 

    By digitizing mathematical knowledge inside appropriate computational contexts that understand about the topics, one can use the digitized knowledge to automatically generate more and higher level knowledge

     

     

    Challenges


    1) how to identify, test and organize the key blocks of information,

     

    2) how to access it: the interface,

     

    3) how to mathematically process it to automatically obtain more information on demand

     

     

     

     

                                               Three examples


    Mathematical Functions

     

    "Mathematical functions, are defined by algebraic expressions. So consider algebraic expressions in general ..."

    The FunctionAdvisor (basic)

     

    "Supporting information on definitions, identities, possible simplifications, integral forms, different types of series expansions, and mathematical properties in general"

    Examples

       

    General description

       

    References

       

     

    Differential equation representation for generic nonlinear algebraic expressions - their use

     

    "Compute differential polynomial forms for arbitrary systems of non-polynomial equations ..."

    The Differential Equations representing arbitrary algebraic expresssions

       

    Deriving knowledge: ODE solving methods

       

    Extending the mathematical language to include the inverse functions

       

    Solving non-polynomial algebraic equations by solving polynomial differential equations

       

    References

       

     

    Branch Cuts of algebraic expressions

     

    "Algebraically compute, and visualize, the branch cuts of arbitrary mathematical expressions"

    Examples

       

    References

       

     

    Algebraic expresssions in terms of specified functions

     

    "A conversion network for arbitrary mathematical expressions, to rewrite them in terms of different functions in flexible ways"

    Examples

       

    General description

       

    References

       

     

    Symbolic differentiation of algebraic expressions

     

    "Perform symbolic differentiation by combining different algebraic techniques, including functions of symbolic sequences and Faà di Bruno's formula"

    Examples

       

    References

       

     

    Ordinary Differential Equations

     

    "Beyond the concept of a database, classify an arbitrary ODE and suggest solution methods for it"

    General description

       

    Examples

       

    References

       

     

    Exact Solutions to Einstein's equations

     

     

    Lambda*g[mu, nu]+G[mu, nu] = 8*Pi*T[mu, nu]

     

    "The authors of "Exact solutions toEinstein's equations" reviewed more than 4,000 papers containing solutions to Einstein’s equations in the general relativity literature, organized the whole material into chapters according to the physical properties of these solutions. These solutions are key in the area of general relativity, are now all digitized and become alive in a worksheet"


    The ability to search the database according to the physical properties of the solutions, their classification, or just by parts of keywords (old paradigm) changes the game.

    More important, within a computer algebra system this knowledge becomes alive (new paradigm).

    • 

    The solutions are turned active by a simple call to one commend, called the g_  spacetime metric.

    • 

    Everything else gets automatically derived and set on the fly ( Christoffel symbols  , Ricci  and Riemann  tensors orthonormal and null tetrads , etc.)

    • 

    Almost all of the mathematical operations one can perform on these solutions are implemented as commands in the Physics  and DifferentialGeometry  packages.

    • 

    All the mathematics within the Maple library are instantly ready to work with these solutions and derived mathematical objects.

     

    Finally, in the Maple PDEtools package , we have all the mathematical tools to tackle the equivalence problem around these solutions.

    Examples

       

    References

       

     

    Download:  Digitizing_Mathematical_Information.mw,    Digitizing_Mathematical_Information.pdf

    Edgardo S. Cheb-Terrab
    Physics, Differential Equations and Mathematical Functions, Maplesoft

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