As a user of Maple 13, namely in computations on General Relativity & Tensor Calculus, I would like to let you know I just got, using Maple 13, the WRONG SIGN (positive Riemann scalar curvature in stead of correct NEGATIVE Riemann scalar curvature) in studying a threefold used as a 'Public Space' by Milne many years ago.

The square of the distance on the said threefold is dE^2=dR^2+(c*t0)^2*sinh(R/(c*t0))^2*(dtheta^2+sin(theta)^2*dphi^2) and you might be interested...

Although I mostly post about parallel programming, my background is in algorithms and data structures.  I have a soft spot for sorting algorithms.  It probably started when I did some research into adaptive sorting as part of my coursework.  Anyway, someone added sound to visualizations of different sorting algorithms.  I'm not sure if it really helps explain the algorithms any better, but it does make them more interesting to watch.

http://www.geek.com/articles/geek-cetera/sorting-algorithms-quite-boring-until-you-add-sound-effects-20100819/

Darin

I used to have a blog entry which contained an except from an Isaac Asimov story entitled "The Feeling of Power".

I had removed that blog entry, but here is a link to the full text.

I was recently reminded of it by two things. The first was that I was reading a blog entry at Walking Randomly which mentioned Maple 14. And I remembered noticing a page on that site before. And the second was ISSAC 2010.

On Tuesday August 10, 2010, the first meeting of an ad hoc group focused on exploring the use of MapleSim in the engineering curriculum met at McMaster University, Hamilton, Ontario, Canada.  Faculty from McMaster University, Kettering University, Lawrence Technical University, University of Waterloo, Ryerson University, University of Ontario Inst. of Technology, and the State University of New York (Buffalo and Binghamton).

The full-day workshop provided an ideal...

I've received a suggestion offline saying that I should animate the Pacman. There are two items to animate: Pacman's mouth and pac-dots. To review how pacman's mouth moves, please have a quick look at Google Pacman doodle.

Pacman's mouth only has three stages: open, half open and close. Let's take the pacman that I created in the previous post. Each frame of the animation is done by adjusting the radian values of the "pie" (aka Pacman's body and mouth).

Today is my birthday, and in fact it is also the birthday of at least one other Maplesoft employee (not surprising since more than 23 people work here - considering the generalized birthday problem, I even know of 3 people here who share the same birthday).  Of course, it turns out that birthdays are not evenly distributed through out the year and so I wanted to know if someone with an August birthday is more likely to share than someone with an April birthday. 

Just for fun, I've created a Pac-Man using Maple's plot command:

body := plottools[pieslice]([0, 0], 5, (1/6)*Pi .. 11*Pi*(1/6), color = yellow):
eye := plottools[pieslice]([-1, 2], .5, 0 .. 2*Pi, color = black, filled = true):
plots[display](eye, body, axes = none);

The hairpiece for Ms. Pac-Man can be added easily:

In a previous post, I promised to write about testing the quality of pseudo-random number sequences.  I'll post later about some of the statistical tests often used, but I first wanted to mention a sort of practical test one can do. One of the many things you might want to do with pseudorandomly generated numbers is Monte Carlo integration/simulatation/etc.  As mentioned by acer in this comment, Monte Carlo integration can be shown to work better with some of the pseudorandom number generators (PRNGs) which are considered inferior in a statistical sense.  In this post, we will play with a simple Monte Carlo approximation of π.

I recently celebrated my 10-year anniversary at Maplesoft. I've enjoyed my time here, working with a terrific group of colleagues, and I hope to be here for many more years to come. Part of the satisfaction comes from being able to interact with this wonderful user community.

I also celebrated the 20th anniversary of the plot code, parts of which I've had the pleasure of maintaining and improving over the past 10 years. Actually, I believe it is closer to 25 years old...

This week, I had the pleasure of attending a rock concert with my son Eric who is now about to turn 15 and who has turned out to possess non-trivial interests and talents in music. The concert was by the band Rush who, to the uninitiated, would be yet another big, loud, over-produced rock band. But to a generation of technocrats (e.g. yours truly) educated from the late 1970’s and on, they are the band of choice due to an intriguing mix of musicianship, technological...

Since the FIFA World Cup final is approaching quickly, I have created this animated Netherlands flag.  It is for my Dutch acquaintances to cheer for their favourite team during game.

with(plots):
p := [ seq( 
          plot( [ seq((1/4)*sin(x+`if`(j > i, 1, 0))+1+2*i, i = 0 .. 3) ],
              x = 0 .. 2*Pi, y = 0 .. 8, 
              color = [white, blue, white, red], filled = true, axes = none), 
          j = [0, 1, 2, 3, 4, 3, 2, 1])

Happy Dominion Day.  

acer

The term “from months to days” is a favorite slogan of mine and I have relied on it religiously for over two decades to illustrate the fundamental benefit of symbolic computation. Whether it’s the efficient development of complex physical models using MapleSim, or exploration of parametric design surface equations (my dissertation) using good old fashioned Maple V Release 2, the punch that symbolic computation provided was to automate the algebraic mechanics...

Has the 'tabbing nuisance', as reported in I declare defeat: rolling back to Maple 9.5, been resolved in Maple 12+? And what about the 'XML-contamination', as also mentioned?

PS: Congratulations to MaplePrimes for a visually very appealing interface. With the migration to this new interface, I have finally been able to gain again access to my account, this partly explaining...

A long while ago, I wrote a couple posts (part1 and part2) about mining data from the US SSA website.  I subsequently adapted the code from those blog posts into a visual application with sliders and interactive plots.  If you have played with the new ?MapleCloud functionality in Maple 14, you may have seen it posted already.