| Re: [eigen] about .lazy() |
[ Thread Index |
Date Index
| More lists.tuxfamily.org/eigen Archives
]
- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] about .lazy()
- From: Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>
- Date: Tue, 25 Aug 2009 15:59:36 +0200
- Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type :content-transfer-encoding; bh=/XNq2iT4GgpZwINGqb1I48BqT5yxKEtC1wez8hWFcJI=; b=xoOotiV9klbYA2sh8kdyNFO7EJM3sLP2qi26wdGa+/a2F/38frEt4a9cvEJxY/agI4 Tt6xa1J0lq6OWc+U4GuxMVURfipak8ZHuJT8cl/ExoA1XiKYzCiww+ROYI96FJ9GexZN z+KcBEp4TH/ppKaqUqntTzVqsiA+Vpj1dW2ss=
- Domainkey-signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=TLKfqFDpJE7hAlT2netzKCIXH1HymcK67BOZK++1qFVqMd/DnvSBK1AAFNQJYQH6SQ bT+0As4HNIyirpdr/vF/4+V8RwfIRbAFi/iAbptan5TGzdzCcPVJTny0NQ9vm9YPMkq5 Zxh13zQM1qui3CcRkrBLIDpgILYDjrPQId/8E=
Hi,
On Sat, Aug 15, 2009 at 10:48 PM, Benoit Jacob<jacob.benoit.1@xxxxxxxxx> wrote:
> (...) For example the
> Transpose expression. And even Block if you take blocks on both sides
> of an assignment (think row(i) = col(j)). So actually, a lot of
> expressions "may alias" (...)
I am wondering whether following the reasoning used for operator* for
matrices, all operators that might alias should be implemented in a
conservative way. I.e. with introducing temporaries as long as
noalias() is not used explicity? I don't see why we should not
implement the same level of safety we have for operator* for all
potentially aliasing operations. I would be probably desired to have
something like this
MatrixXd a(3,4);
a << 1,2,3,4,5,6,7,8,9,10,11,12;
a = a.block(0,0,3,2);
woking properly...
- Hauke