Re: [eigen] MathFunctions.h patch

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

Thanks, pushed to the default branch.

Do you need it in 2.0?

Benoit

2010/1/7 Trevor Irons <trevorirons@xxxxxxxxx>:
> Patch attached.
>
> Thanks,
>
> Trevor
>
>
> 2010/1/7 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
>>
>> 2010/1/7 Trevor Irons <trevorirons@xxxxxxxxx>:
>> > Ah, I was surprised, but understand.
>> >
>> > I am doing electromagnetic modelling, and this is necessary sometimes
>> > (often).
>> >
>> > From what I can tell std::sqrt returns the root in either the first or
>> > fourth quadrant of the complex plane, same as FORTRAN (I think).
>> > (Arbitrary, but useful for me)
>> >
>> > I can work around using for loops if you prefer not to include this in
>> > Eigen, but my *very* small vote would say to support it.
>> >
>> > I guess I don't really understand your argument fully. Is the behaviour
>> > of
>> > std::sqrt() for complexes not mandated by the C++ standard committee?
>> > Or
>> > does this vary across compilers? If it is at least supposed to be
>> > consistent, then all you are doing is passing along expected behaviour
>> > of
>> > C++ to Eigen users, right?
>>
>> Right, so, since you have a real use case, which is what I was trying
>> to filter for, let's go for it.
>> Could you just please generate a real patch:
>>  - configure your id
>>  - hg commit, write your commit msg
>>  - hg export tip
>>
>> http://eigen.tuxfamily.org/index.php?title=Developer%27s_Corner#Generating_a_patch
>>
>> Thanks
>> Benoit
>>
>> >
>> > Thanks,
>> > -Trevor
>> >
>> >
>> > 2010/1/7 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
>> >>
>> >> It is on purpose that we excluded sqrt for complex numbers:
>> >>  - there is no canonical choice between the 2 determinations of the
>> >> square
>> >> root.
>> >>  - no important use case was known to us.
>> >>
>> >> Do you have a use case?
>> >>
>> >> Benoit
>> >>
>> >> 2010/1/7 Trevor Irons <trevorirons@xxxxxxxxx>:
>> >> > Any problem adding the following patch, or something similiar, to
>> >> > MathFunctions.h to support std::complex<>.sqrt() ?
>> >> >
>> >> > 218d217
>> >> > < inline std::complex<float> ei_sqrt(std::complex<float>x)  { return
>> >> > std::sqrt(x); }
>> >> > 256d254
>> >> > < inline std::complex<double> ei_sqrt(std::complex<double>x)  {
>> >> > return
>> >> > std::sqrt(x); }
>> >> >
>> >> >
>> >> > -trevor
>> >> >
>> >>
>> >>
>> >
>> >
>>
>>
>
>