PCA is a linear dimensionality reduction technique. Many non-linear dimensionality reduction techniques exist, but linear methods are more mature, if more limited.

In their hearts, computers are sequential beasts. Their power comes from being able to break down the largest tasks into tiny steps that can be performed one after another. Often, though, our users need to see things occur in a single instantaneous step or see multiple tasks performed simultaneously.

A typical example, and one that every game engine must address, is rendering. When the game draws the world the users see, it does so one piece at a time — the mountains in the distance, the rolling hills, the trees, each in its turn. If the user watched the view draw incrementally like that, the illusion of a coherent world would be shattered. The scene must update smoothly and quickly, displaying a series of complete frames, each appearing instantly.

Double buffering solves this problem, but to understand how, we first need to review how a computer displays graphics.

If the code isn’t working the way you think it should, then something about your assumptions is wrong. Look through code to ensure that all the pieces work as you expect them to. Step through the code with a debugger if you can and look for any surprises.

Ultimate Quality Development System is key to software project Twisted's ability to release stable, reliable code.

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