Re: [boost] definition of complex norm

From: Luis Pedro Coelho (deepblack9_at_[hidden])
Date: 2001-11-02 02:52:46

Em Quinta, 1 de Novembro de 2001 13:34, escreveste:
> In the current gcc, norm of complex is defined in terms of abs.  I
> believe the definition should be changed to:
>
> norm(z) = sqr(real(z)) + sqr (imag (z))
>
> My reasons are:
>
> 1. More efficient
> 2. Works for complex<int> (important in DSP)
> 3. Possibly more accurate

I suppose you meant sqr(x) = x * x.

This number above sqr(real(z)) + sqr (imag(z)) is indeed useful, but it is 
not the usual norm, it is the square of the usual norm. Call it norm_squared 
or even norm2 to avoid misunderstandings.

Regards,
-- 
Luis Pedro Coelho.
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