Re: [AD] div-by-zero... math3d.c

[Ben Davis <bnd25@xxxxxxxxxx>]

On Monday 17 March 2003 4:30 pm, Sven Sandberg wrote:
> I think you are right about the zero vector, we may well leave the
> result undefined.  But I also think the current implementation may give
> strange results for vectors close to but different from zero, because if
> their squares are zero then vector_length() returns zero.  What about
> the following algorithm:
[snip]

I honestly think the best solution would be to do the arithmetic using 
double-precision values. A float can go down to 1e-38 before it becomes 
subnormal (and slow) and starts losing precision. A double can go down to 
1e-some_three_digit_number. So the smallest float, cast to double, and 
squared, would be will within the range of a double. As for efficiency, the 
FPU on an x86 processor probably does everything using 10-bit (the 
nonstandard 'long double') precision anyway, so we're not losing anything.

Ben