You shouldn't write any code that relies on a particular implementation
of hashCode because it could change. But having used hashCode a lot
I'm suspecting that you want to verify that the code produces an even
distribution. Some classes in java do not - for example, the last time
I looked at Integer.hashCode it just returns the integer. Here's the
implementation of Tuple3f.hashCode:
long bits = 1L;
bits = 31L * bits + (long)Float.floatToIntBits(x);
bits = 31L * bits + (long)Float.floatToIntBits(y);
bits = 31L * bits + (long)Float.floatToIntBits(z);
return (int) (bits ^ (bits >> 32));
So it's using a very well distributed algorithm, combining the
idea of multiplying by a prime number and also XOR'ing.
-Paul
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****************************************************************************
> Delivered-To: [EMAIL PROTECTED]
> Delivered-To: [EMAIL PROTECTED]
> Date: Thu, 23 Aug 2001 11:16:17 -0700
> From: R Vegan <[EMAIL PROTECTED]>
> Subject: [JAVA3D] HashCode for Tuples
> To: [EMAIL PROTECTED]
>
> Hi Sun Team:
>
> I am interested in finding out explicit info. on how the
> hashcode for a Tuple object is generated - the API says
> it is derived from the elements of the object. Are the hashcodes
> XOR-ed together ? with prime coefficients or none ? Would you
> please give the details, in particular, for Point3f, Point3D,
> Tuple2i (?) and Tuple3i (?).
>
> Thanks in advance
>
> Raj Vaidya
>
> ============================================================================
> Raj Vaidya, PhD
> R&D
>
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