# Welcome to Stoney’s Zone

• ## The Even-more Complete List of Hex Words

I realized that I was being insufficiently lee7, so I added S, T, and Z, converting into 5, 7, and 2. This produced a much longer list, of course.

• ## The Complete List of Hex Words

While converting some code to 64-bit on Snow Leopard, I discovered that character literals are ints, so I couldn’t use them for 8-byte longs. The alternative is readable hex constants.

• ## 2D Matrix Decomposition

This demonstrates the polar decomposition of 2D matrices into their angle, scale, and shear components. The polarDecomp algorithm is taken from Shoemake & Duff “Matrix Animation and Polar Decomposition“, 1992.

• ## Mirroring git respositories to DreamHost

Casper Fabricius has a nice shell script for creating new git repositories on DreamHost. Unfortunately, this works only for creating new repositories.

• ## Defining new format wrappers in Mathematica

One problem I had with the expression-to-C converter is that CForm converts negations of terms into a negation of parenthesized terms.

• ## Converting symbolic Mathematica expressions to C code

I frequently use Mathematica to rearrange or solve symbolic equations to use in C++ programs. While Mathematica is quite powerful for that, it has no facility to hoist common subexpressions into variables.

• ## Adding a keyboard shortcut to Mathematica V7

(updated 2009-03-23 to add the backslashes that disappeared between my blog editor and WordPress) In Mathematica, typing index brackets is clumsy, as one has to type esc-[[-esc then esc-]]-esc. I found a way to modify the Edit menu to add a shortcut for this.

• ## Pixel-perfect Graphics, Revisited

Mathematica 7 introduces a new Image function that eliminates all the hassle previously necessary to create and export pixel-perfect raster images.

• ## What is a sampling test image?

I was asked what the purpose is of the test image in my previous post, and why the alpha was set to 0.01 rather than 0 in alternating pixels.

• ## Exporting Pixel-Perfect Graphics in Mathematica

I keep having to figure out how to export pixel-perfect raster images from Mathematica, which I use for test images with my software. I found that it’s simpler to use ArrayPlot than Raster now, so I’m documenting this for my future use (and any one else’s).