Number accuracy in moi.ini

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 From:  mickelsen
3041.1 
While I was editing the moi.ini file for colors on the axis arrows I noticed this entry:
GridSize=0.025000000000000001
Other entries had similar values with a non-zero digit at the very end. What is the purpose for the "1" way out at the end, and what would happen is I removed it?

Mark
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 From:  Michael Gibson
3041.2 In reply to 3041.1 
Hi Mark,

> What is the purpose for the "1" way out at the end,

Well, it's just an artifact that numbers on the computer are built on a "base 2" definition, and there can sometimes be a very tiny inaccuracy involved when converting into a base 10 definition like humans are used to seeing.

There is a bunch more information describing this in the article here:
http://en.wikipedia.org/wiki/Floating_point


For values that are shown in the regular UI (like the x,y,z coordinates that show when you are picking a point) MoI will round those to a fixed number of decimal places, which you can set under Options > General > Decimal display.

For values written to the .ini file though, it does not try to round them, it tries to write as many decimal places as it can.


> and what would happen is I removed it?

Nothing bad, but it will just appear again when the values get written to the moi.ini again.

That will happen for values that are not possible to be 100% exactly represented by the floating point numeric system on the computer.

I guess I could round these off to something like 8 decimal places to make it look nicer, I'll take a look at that.

- Michael
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