Re: [eigen] Constructing a matrix by scalar*

[Benjamin Schindler <bschindler@xxxxxxxxxxxxxxx>]

Hell, I would love that to happen. Their math stuff is pretty 
unstructured and chaotic. But that's not something to be done during a 
masterthesis...
I actually thought about it. But they have type independent arrays (And 
I don't like them...) with dynamic resizing etc...

Thanks a lot for the advice. I guess the tutorial would have told me 
just as well - I just looked over the constructors...


Gael Guennebaud wrote:
> I forgot to mention: a better option would be, of course, to port VTK 
> to eigen2 ;)
>
> gael.
>
> On Thu, Nov 27, 2008 at 3:58 PM, Gael Guennebaud 
> <gael.guennebaud@xxxxxxxxx <mailto:gael.guennebaud@xxxxxxxxx>> wrote:
>
>     Hi,
>
>     typedef Map<Vector3f> Vector3fm;
>
>     then Vector3fm exactly represents what you were looking for. For
>     instance:
>
>     float d[3] = {1,2,3};
>     Vector3fm v(d);
>
>     v += Vector3::Random();
>
>     there is no copy, v stores only a single pointer. You can also
>     directly use a "Map" object:
>
>     Vector3f::Map(d) += Vector3::Random();
>
>     gael.
>
>
>     On Thu, Nov 27, 2008 at 3:45 PM, Benjamin Schindler
>     <bschindler@xxxxxxxxxxxxxxx <mailto:bschindler@xxxxxxxxxxxxxxx>>
>     wrote:
>
>         Hi
>
>         I'm currently working with vtk and it has a pretty ugly way of
>         dealing with vectors /- /at least in my opinion. So I thought
>         I could use eigen2 to do some of the fixed-size vector-math
>         I'm doing. I found that Matrix has a data() function which
>         returns a raw pointer to the data so that's good. But What I'm
>         missing is a constructor which constructs a i.e. vector3f from
>         a float pointer without copying the data. If I want to
>         efficiently interact between vtk and eigen, I think this is
>         very crucial.
>
>         Is this somehow possibel?
>
>         Thanks
>         Benjamin
>
>         ---


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