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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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  • We have just released the MapleSim Driveline Component Library. Built with the involvement of several transmission manufacturers, this MapleSim add-on covers all stages in the powertrain, from the engine to the differential, wheels, and road loads, as well as vehicle dynamics. MapleSim and the MapleSim Driveline Component Library make it much easier for transmission manufacturers to reduce power loss through improved designs, resulting in more efficient vehicles.

    For...

    I think this is more of a blog but we don't have that option so it is here in a post.  Occassionally I like to use Maple to grab data from the internet. 

    The problem is that everyone seems to be changing the formats of their webpages.  Out with the old simple txt fomatted data webpages and in with the new html formatted webpages. The trouble with that is, if you already have a worksheet setup to manipulate the data using sockets or HTTP[Get] you...

    I have remarked on this ever since the launch of the second incarnation of mapleprimes. And I recall others expressing similar feelings.

    1. It should be possible to "vote" for comments in the same way as we can vote for "answers".
    2. The comments should be listed, right there next to Answers:

                          

       This is a promissory Maple package, which is rarely used (I found nothing  in MaplePrimes and in Application Center.). Let us see the ?padic package. It is well known that the field of rational numbers Q is not complete. For example, there does not exist a rational number k/n such that k^2/n^2=2. There are only two ways to complete Q ( http://en.wikipedia.org/wiki/Ostrowski's_theorem ) .  The first way is to create the field of real numbers R including Q. Every real number can be treated as a decimal fraction sum over [k in K] of a[k]*10^(k) with a[k] in {0,1,2,3,4,5,6,7,8,9}, finite or infinite. For example, the numbers 0.3+O(0.1), 0.33+O(0.01), 0.333+O(0.001), 0.3333+O(0.0001), ...  approximate the number  1/3.
       The second way is as follows (see http://en.wikipedia.org/wiki/P-adic_number  for more details). We choose a prime number p and consider the valuation v[p] of a rational number k/m=p^n*a/b <>0 where integers are supposed to be irreducible :v[p](k/m):=p^(-n) , v[p](0):=0. The completion of Q up to this valuation is the field of p-adic numbers Q[p] (also including Q).  Every p-adic number can be treated as a p-adic fraction sum over[k in K]of a[k]* p^(k) with a[k] in {0, 1, 2, 3, p-1}. For example, the numbers 2, 2+O(5),2+3*5+O(5^2),2+3*5+5^2+O(5^3) approximate the number 1/3 in Q[5]. These can be obtained with Maple as follows.
    > with(padic);
    > evalp(1/3, 5, 1);
                               2
    > evalp(1/3, 5, 2);
                            2+O(5)
    > evalp(1/3, 5, 3);
                              2+3*5+O(5^2)
    > evalp(1/3, 5, 4);
                             2+3*5+5^2+O(5^3)
        The field Q[p] is a very strange object. For example, the set of integers is bounded in Q[p] because v[p](k) <= 1 for every integer k. Another striking statement: the sequence p^n tends to 0 in Q[p] as n approaches infinity. The functions expp(x), logp(x), sqrtp(x) and the others are defined in the usual way as the sums of power series (see ?padic,functions for more details). For example,
    > Digitsp := 12;
    > logp(2+3*5+5^2, 5);

                   5+5^2+4*5^3+5^4+3*5^6+4*5^8+3*5^9+5^10+3*5^11+O(5^12)
    > cosp(x, p, 2);

                                padic:-cosp(x, p, 2)
    > eval(subs(x = 0, p = 5, padic:-cosp(x, p, 2)));

                                 1
    > eval(subs(x = 3*5, p = 5, padic:-cosp(x, p, 2)));

                                 1                            
        The definition of the limit of a sequence in Q[p] is identical to the one in R (of course,  abs(x[n]-a)<epsilon should be replaced by v[p](x[n]-a)<epsilon for every rational epsilon) and the same with the derivative. But every continuous function is picewise-constant. There also exists a non-injective function on Q[p] having the  derivative 1 at every point of  Q[p] . It should also be noticed that the radius of convergence of the expp(x):=sum(x^n/n!,n=0..infinity) series equals p^(-1) if p >2 and 2^(-2) if p=2. Next, there exists a Haar measure d[p](x)=:dx on Q[p] such that d[p](Z)=1. The definite integral of a real-valued function f(x) over a subset D of Q[p] with respect to  dx is defined in certain cases. For example, the definite integral of 1 over
    the ball B(0,p^n):={x in Q[p]: v[p](x)<=p^n} with respect to dx equals p^n, ie. the radius of B(0,p^n). It is clear that there does not exist any analog of the Newton-Leibniz formula in the p-adic case. Because of this reason every calculation of every definite p-adic integral is a hard problem.

            There are a lot of good and diffent books on p-adic analysis. In particular, see http://www.google.com/search?tbm=bks&tbo=1&q=p-adic&btnG= ,  http://books.google.com/books?id=H6sq_x2-DgoC&printsec=frontcover&dq=p-adic&hl=uk&ei=IgFuToupO8SL4gTE-tDOBA&sa=X&oi=book_result&ct=result&resnum=6&ved=
    0CEYQ6AEwBQ#v=onepage&q&f=false
    , and http://books.google.com/books?id=2gTwcJ55QyMC&printsec=frontcover&dq=p-adic&hl=ru&ei=UAxqTuabD5HGtAamhryxBA&sa=
    X&oi=book_result&ct=result&resnum=4&ved=0CDkQ6AEwAw#v=onepage&q&f=false
    as a good introduction to the topic.
         Why  is it so important? Which are applications? There are indications that the space  we live in has not  the Archimedean property (see http://en.wikipedia.org/wiki/Archimedean_property) on a very small scale. To verify this hypothesis is  a dozen times more expensive than  the large hadron collider
     (see http://en.wikipedia.org/wiki/Large_Hadron_Collider ). However, the mathematicians already develop the necessary mathematical tools, in particular, p-adic analysis.  Concerning other applications, see the answer by Anatoly Kochubei in
     http://mathoverflow.net/questions/62866/recent-applications-of-mathematics.

    Edit. The vanishing text and some typos.

     

    restart; interface(version); # Maple 15
    Digits:=40;
    # symbolic expression
    t:=1/292/(-77796+62196*I*3^(1/2))^(1/3)*73^(1/2)*
      ((-77796+62196*I*3^(1/2))^(1/3)*
      (-3*(-77796+62196*I*3^(1/2))^(2/3)-
      7812+688*(-77796+62196*I*3^(1/2))^(1/3)+
      3*I*3^(1/2)*(-77796+62196*I*3^(1/2))^(2/3)-7812*I*3^(1/2)))^(1/2)
      -0.3; # <--- does that give the trouble ?
    simplify(t); # makes it a float ...

      0...

     

                    

    3D Paper Physical Model

    We are looking for a Maple Wizard to join our team, based in California. US citizenship is an absolute requirement. Please send me a message if you are interested or know someone who might be.

    thanks

     

    The MRB constant =    sum((-1)^n*(n^(1/n)-1), n = 1 .. infinity)

     

    Concerning the following divergent and convergent series, we see that

    sum((-1)^n*(n^(1/n)-x), n = 1 .. infinity)=

    A list of small graphs with associated pictures and tables of
    values of various graph invariants.

    The graph invariants were made using Maple programs which uses
    the networks and GraphTheory packages.

    A picture presents some inequality conjectures between the graph invariants.

    http://www.msci.memphis.edu/~speeds/

    Sam Speed   August 29, 2011

    Td_Group_Adapted_Dou.zip 

    Point Groups typical to cubic crystals are Tetrahedral (Td) in Zinc-blende and Octahedral (Oh = i x Td) in Diamond.  Symmetry operations give rise to the widespread application of Group Theory most notably to generate basis functions which transform according to irreducible representations.  Much work has been accomplished using Single Group basis, compatible...

    I think I will continue posting some good questions from
    Fridays Killer Questions 7city Learning:

    Question:

    There was a hit-and-run incident involving a taxi in a city in which 85% of the taxis
    are green and the remaining 15% are blue. There was a witness to the crime who
    says that the hit-and-run taxi was blue. Unfortunately this witness is only correct
    80%...

    Question:

    Let say you have a revolver with six chambers. There are two bullets in the gun. The bullets are
    located in two chambers next to each other. You now want to play Russian roulette. You spin
    the barrel so that you don’t know where the bullets are and then pull the trigger. We assume
    that you don’t kill yourself with this first attempt. Now assuming that you want to maximize
    the chance of not killing yourself is it...

    And so with this provocative title, "pushing dsolve to its limits" I want to share some difficulties I've been having in doing just that. I'm looking at a dynamic system of 3 ODEs. The system has a continuum of stationary points along a line. For each point on the line, there exist a stable (center) manifold, also a line, such that the point may be approached from both directions. However, simulating the converging trajectory has proven difficult.

    I have simulated as...

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