Re: [eigen] eigen sqrt compilation error

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

oh and there is another "nuclear option":

add a convenience #include<Eigen/Eigen> that includes them all. And
then keep the separate headers for the users who want every % of
compilation speed.

The idea is that Core and Array are the 2 biggest modules, so
Eigen/Eigen won't be much slower than including them two.

Benoit

2009/6/19 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
>
> 2009/6/19 Gael Guennebaud <gael.guennebaud@xxxxxxxxx>
> >
> > On Fri, Jun 19, 2009 at 12:29 PM, Patrick Mihelich
> > <patrick.mihelich@xxxxxxxxx> wrote:
> > >
> > > On Fri, Jun 19, 2009 at 12:37 AM, Moritz Lenz <mlenz@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
> > >>
> > >> Considering the number of times people make this error (forgetting to include it), what about including it by default? Is there a very good reason not to do it?
> > >
> > > I wonder this too. I ran into this error when I started using Eigen, and it seems to pop up regularly on the list. What exactly is the cost of including <Eigen/Array> in the core? How much does it increase compile times?
> >
> > on my high end computer with gcc 4.3.2 -O2 -DNDEBUG, much less time
> > than to compile: Vector3f a, b; cout << a+b;, so something around 0.02
> > sec.
>
> On my computer I tried this program:
>
> #include <Eigen/Core>
> //#include <Eigen/Array>
>
> using namespace Eigen;
>
> int main() {
>  Matrix3d m = Matrix3d::Identity();
>  Matrix3d n = m+m;
>  Vector3d v; v << 1, 2, 3;
>  Vector3d w = v+v;
>  w = m * w;
>  std::cout << w << std::endl;
> }
>
> with g++ 4.3.3. I repeated the compilation 10 times.
>
> The #include<Eigen/Array> increases compilation times by 2.5% and the
> memory usage is not affected.
>
> I'm OK to consider this reasonable, especially as other modules like
> Geometry already include Array.
> What's your opinion?
>
> The next question would be: should we merge the Array/ files into
> Core/ or just #include<Array> in Core.
>
> Benoit