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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] inconsistent cwise() support
- From: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
- Date: Mon, 16 Nov 2009 15:40:04 -0500
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2009/11/16 Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>:
> On Mon, Nov 16, 2009 at 7:22 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
> wrote:
>>
>> It seems like what you want is Gael's proposal for "true array support".
>
> Not really, since I am really required to work on matrices - actually I was
> working on spectral clustering involving eigenvalue decompositions (so real
> linear algebra stuff).
>
>>
>> vector - scalar is not a standard operation; it doesn't have a
>> geometric meaning. Actually matrix - scalar is sometimes used as
>> matrix - scalar*Identity, so that's another reason not to let it mean
>> coeff-wise substraction.
>
> I totally agree, I was just thinking about consistingly supporting (I do
> even volunteer to implement it)
>
> .cwise() += | -= | /= | *=
oh, i see.
Yes, I agree with your proposal, it would be cool if you implement it.
It's true that there's no reason not to let .cwise syntax always work.
Benoit
>
> and not in general
>
> MatrixBase::operator += etc.
>
> I just think that some problems (formulated in an algebraic framework) do
> sometimes need individual rescaling and sometimes even shifting when you
> need to work e.g. on zero-mean input data.
>
> - Hauke
>