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Re: gEDA-user: pcb crooked traces



At 11:26 AM 10/12/2010, you wrote:

But if we limited everything to 2m, using unsigned integers, we'd
be okay with 32 bits. I'm not sure what you're saying here.

Having said that, I still want negative coordinates. So do we need
to limit things to 1m? Yuck.

He is saying that to avoid overflow in internal calculations, you could have parts up to 1 meter on a board up to 1 meter with the part placed at the upper edge of the board putting the upper edge of the part at 2 meters.


Well, ``probably slower'' isn't a good reason for anything. I doubt
your speculation on both 32- and 64-bit machines, so testing will
need to be done.

WHOA!!! We should actually measure how much the application would slow rather than speculate or use pointless metrics such as how fast a test program doing nothing but a math operation runs... what a concept!!!

So who is going to bell the cat?

Another thought. Using 1 nm as the base unit does everything anyone wants, but limits the max size board on 32 bit machines. But do we really need 1 nm resolution? This allows exact representation in nm of 0.01 mil in inches. Do we need exact representation of 0.01 mil? Would 0.1 mil be adequate? Using 10 nm as the base unit internally gives exact representation down to 0.1 mil and allows much finer resolution, just not exact representation in inches. With a 10 nm base unit the max board size goes to 20 meters which certainly is enough for everyone, including those wishing to design kitchens!

Durn metric system! Why can't our system be good enough for the rest of the world? :-\

Rick


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