Tuesday, April 12, 2011 Lethbridge

7:00 am

The days are staying cool - only single digit highs for the rest of the week. While cleaning the winter debris from the front yard yesterday I noticed a few flowers were beginning to emerge from the ground. I will try to take a few photos today. But the main task will be to remove two juniper bushes from the back yard in anticipation of a new landscaping plan.

Addendum: The juniper bushes have been removed.

Here are a few photos of the emerging plants in our front yard:

The first two images are amazing. When I was cleaning up some of the dead leaves along the side of the house yesterday there was no greenery at all. But I could see just the beginning of a bud emerging from the surface. Here is the view this morning.

11:30 am tag: Mathematics

A very satisfying session. I carefully went through the steps to verify the COSINE FORMULA. This took about an hour but I now understand it. I also understand the Scharz inequality. This completes the material for section 1.2 on Lengths and Dot Products.

I then opened the APL software package and quickly created two vectors of size 3 and computed their dot product using the APL notation for dot product which is + . x . This notation is actually quite clever as it makes explicit the general idea of first creating a collection of products and then add them all up. Once the notation is explicit it becomes possible to think of other possibilities for inner products where, for example, one first forms a collection of sums and then multiplies them all together. Truly fascinating.

Here is the screen display for the APL session:

At this stage I only wanted to verify that I remembered the notational conventions for finding the inner product of two vectors. Not bad, considering it was almost 40 years ago. The Strang textbook mentions both MATLAB and PYTHON as too computing languages that process vectors and matrices as single entities. APL is a third approach which I think is superior to both of the conventional modern approaches.

9:30 PM tag: Literature

I have finished reading "The Lacuna". Impressive! This is a truly great novel. Kingsolver must truly love her country to write such a powerful novel. The unwritten assumption is that a country can benefit from knowing its own history.

The book deserves a large parting image.

10:00 PM tag: Technology

I now have 3 apps on my iPad, all for reading ebooks. iBook is for the Apple, Kindle is for amazon.com., and Kobo specializes in providing ebooks. All provided both free books as well as ebooks that cost about a third of what the hard-cover would cost.

So far I have bought one book for the Kindle reader, "Information" by James Gleick. This book does not appear to be available for the other two readers. I have "The Picture of Dorian Gray" by Oscar Wilde which was free for the iBook reader. And I am seriously thinking of buying "Autobiography of Mark Twain: The Complete and Authoritative Edition Volume 1" which is available from amazon.com as well as from Kobo.

I like the format and overall features of all three ereaders.

My sense is that the ebook market is rapidly going to become very competitive.

But I do have one large concern. The technology continues to evolve. Thus in a few years I assume that the files I download today will no longer be readable as the devices to read them change. At least with hard copy the books remain relatively timeless.

All three readers provide some form of bookshelf where one can see all the books that have been downloaded from that source. But I am not aware of a way of integrating this information into one personal file.