I have gotten some comments about my new avatar, including a few commenting that while my picture is clear on the blog contributors sidebar, it is "blurry" on my blog posts. I just wanted clear this up.  I am not in the witness protection program; I just really love singular values.  My new avatar, just like my old one, is a rank 4 approximation of a picture of me using the singular value decomposition.

I lived in the UK before making the barely-considered decision to move to Canada.  I still have savings denominated in pounds sterling (all dutifully declared on my Canadian tax return).  Accordingly, I keep a close watch on the GBP-CAD exchange rate so I have some sense of my net worth.

When I arrived in Canada in July 2008, one pound sterling bought $2, down from $2.30 two years before that.  Today, the pound has devalued further and is worth around...

In a series of posts now imported to the Maplesoft blog (starting here), I have been talking about pseudo-random number sequences, but since part of what kicked off this series was a paper on true random number generation (with LASERS!) I thought I would share some routines I wrote that alllow you to use the two main true random number sources available on the web (neither using lasers, sadly).

I ran across something called wordle, somewhat of a quick visual word analysis, a collection of words used collected in an article and put into a collage of large and small font words based on the amount of times they were used. 

Here I have attempted something similar in Maple. 

wordle_project_proce.mw

I slightly modified and shortened...

I just wanted to let everyone know that we recently added some interesting new packages to the Application Center. These packages had been available as third party products. Now, the authors have chosen to make these products freely available to the community through the App Center. Follow the links below to take a look.

Harmonic Analysis

Structural Mechanics

Quaternions

FuzzySets

In this post I'll introduce is a nice visual test of randomness from signal processing. The main idea of this test to look at how a random sequence correlates with itself.

It's been a while since I wrote one of these random posts, but I still have a couple more I wanted to write.  In this post, I want to describe one of the tests used in the paper that initially inspired this series of posts: the Wald-Wolfowitz runs test.  This test is interesting in that it does not test for uniformity

A new edition of Maplets for Calculus  (M4C) is now available.  M4C v1.3 is a collection of 129 maplets for calculus students and instructors.  The 35 new maplets fill in some gaps in the coverage of precalculus and single variable calculus and begin to address multivariate topics. Each maplet provides a customized graphical user interface (using 2D and 3D graphics and animation) to provide immediate, step-by-step guidance through an endless supply of random ...

I would like to pay the attention of the MaplePrimes users
to a Robert Chero application.
This is a Maple package on graphics, which can be implemented in Maple as a usual package.
It  has community rating 4.5 stars. This package can be downloaded from http://www.maplesoft.com/applications/view.aspx?SID=1671.
It was submitted in 2005 when MaplePrimes started. Because of this reason this...

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...

As alluded to in my previous post in this series, one of the most straight forward ways to test if a PRNG is generating good random sequences is by examining the frequency of 0's and 1's.  This is just a couple lines in Maple using Statistics:

(**) r1 := rand(0..1):L := [seq(r1(), i=1..10000)]:
(**) n := nops(L); tally := `+`(op(L));
(**) Statistics:-ChiSquareGoodnessOfFitTest(
      [n-tally, tally], [n/2, n/2], ':-output'=':-hypothesis');

I thought for sure something like this would have already been done in Maple (mapleprimes).  I see it's already been done over at Mathematica.  I must admit I am a bit jealous at how much Mathematica users have done.  So anyways ... something simple

for i from 1 to 10 do
  for j from 1 to 10 do

This is the third post in a four-part series; the earlier posts are Generating...

This is the second post in a four-part series that started with this post: Generating...