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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] MathFunctions.h patch
- From: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
- Date: Thu, 7 Jan 2010 17:37:53 -0500
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Now you got me started on pedantry!
Indeed real numbers are no better than complex numbers; but the subset
of *nonnegative* real numbers is much better: for any nonnegative real
number, there is a unique nonnegative square root.
Benoit
2010/1/7 Mark Borgerding <mark@xxxxxxxxxxxxxx>:
> Benoit Jacob wrote:
>>
>> It is on purpose that we excluded sqrt for complex numbers:
>> - there is no canonical choice between the 2 determinations of the square
>> root.
>
> Just a pedantic note. There are two square roots of real numbers too.
> Conventionally, sqrt(4) returns 2, not -2.
>
> Returning the root in the right half plane (non-negative real) would seem a
> logical generalization of this convention.
>
>
>
>