problem with dot product

Hi guys

I can not understand why in this definition, the dot product of two orthogonal vectors is not zero.

can someone explain me why?

Thanks in advance

Attachments:

dot product.gh, 6 KB

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Permalink Reply by massimiliano on April 23, 2012 at 6:56am

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Permalink Reply by Danny Boyes on April 23, 2012 at 7:02am

It is zero when I opened it.

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Permalink Reply by massimiliano on April 23, 2012 at 7:20am

the problem remains, maybe the cause is some setting of rhino?really i don't understand ...

Please help me

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Permalink Reply by Giulio Piacentino on April 23, 2012 at 7:33am

-1.0057e-15 is zero within 10^-14, or 0.00000000000001 units, tolerance, which means you could consider this 0. You have to always consider tolerance with this type of calculations. This is computation with double-precision floating point arithmetics.

Thanks,

- Giulio
________________
giulio@mcneel.com

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Permalink Reply by Danny Boyes on April 23, 2012 at 7:33am

-1.0057e-15 is the scientific notation for the number 0.0000000000000010057.

It's safe to say that it is 0. The discrepancy is cause by rounding errors in the calculation when using floating point numbers. You can read more about accuracy issues here