IRID-178 Weak Implementation Complex.GetHashCode()

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IRID-178 - Weak Implementation Complex.GetHashCode()

Created: 02/07/2008 19:42:21

Revised: 03/07/2008 09:10:40

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Simply XORing the real and the imaginary part of a complex number leads to most likely appearing hash code collisions (e.g. 1+0i and 0+1i). Thus it is desired to distinguish between the real and the imaginary part.
Proposals:
return real.GetHashCode() ^ imag.GetHashCode().GetHashCode()
or
return real.GetHashCode() ^ (imag + double.Epsilon).GetHashCode()

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Christoph Rüegg

03/07/2008 09:10:40 * CLOSING COMMENT *

Implemented in revision 463:

return real.GetHashCode() ^ (-imag.GetHashCode());

Christoph Rüegg

03/07/2008 08:51:33

Note, since GetHashCode of a Int32 returns itself, the first version is no option. The second version might be broken, too, since for large numbers adding epsilon might not have any effect. I'll use the Number.Increment method instead.