The Even-more Complete List of Hex Words

December 24th, 2009
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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.

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Computers, Software

The Complete List of Hex Words

December 18th, 2009
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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.

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Computers, Software

2D Matrix Decomposition

July 10th, 2009
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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.

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Computer Graphics, Mathematica

Mirroring git respositories to DreamHost

June 11th, 2009
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Casper Fabricius has a nice shell script for creating new git repositories on DreamHost. Unfortunately, this works only for creating new repositories.

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Software , , , , ,

Defining new format wrappers in Mathematica

June 3rd, 2009
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One problem I had with the expression-to-C converter is that CForm converts negations of terms into a negation of parenthesized terms.

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Languages, Mathematica, Software

Converting symbolic Mathematica expressions to C code

June 2nd, 2009
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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.

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Languages, Mathematica, Software

Adding a keyboard shortcut to Mathematica V7

December 29th, 2008
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(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. Read more…

Languages, Mathematica, Software

Pixel-perfect Graphics, Revisited

November 25th, 2008
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Mathematica 7 introduces a new Image function that eliminates all the hassle previously necessary to create and export pixel-perfect raster images.

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Computer Graphics, Languages, Mathematica, Software

What is a sampling test image?

September 8th, 2008
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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.
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Computer Graphics, Computers, Software

Exporting Pixel-Perfect Graphics in Mathematica

September 2nd, 2008
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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).
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Computer Graphics, Languages, Mathematica, Software