yade-dev team mailing list archive

[Anton Gladky <gladky.anton@xxxxxxxxx>]

2010/5/5 Václav Šmilauer <eudoxos@xxxxxxxx>

>
> > Rotate is added in r2200
> Thanks. We should discuss what interface we will follow for Python in
> more detail.
>
> I think it should be similar to Eigen interface, which (for example)
> does not have any Rotate method. The Quaternion*Vector3 multiplication
> is defined, though (try Quaternion(pi,(0,0,1))*Vector3(1,0,0) ), just as
> in c++.
>
>
You think Rotate method will slow down calculation? As for me, it is very
clear to have Rotate method.
You do not need to remember, that rotation is quaternion and vector
multiplication.

But if it makes the simulation slower, I agree, we can delete it off.



> Vectorization is not enabled now (disabled via #defines in
> lib/base/Math.hpp).
>

> Once you've tested eigen, I would like other people to use it, too. If
> there are no issues, we will be able to drop Wm3 before the release.
> OTOH people will have to install libeigen2-dev package (which doesn't
> exist for hardy, but I think everybody will upgrade by then), as I don't
> want to put its whole source in our tree.
>
> Cheers, Vaclav.
>
> PS.
>
> The thing is a little problematic since e.g. Matrix3r+Matrix3r doesn't
> create a new Matrix3r object, but a special matrix addition object (so
> called expression templates, which can be then used to optimize complex
> formulas etc); those objects can be converted to Matrix3r either by ctor
> call or via .eval() method of that object.
>
> That means that in Python we cannot expose e.g. Matrix3r*Matrix3r
> multiplication just by saying .def(py::self * py::self), which reuses c
> ++ operators; instead, we have to create a standalone function taking 2
> matrices which returns the .eval() result, then
> defining .def("__add__",Matrix__add__Matrix) and so on. It is handled
> with macros in py/miniWm3Wrap/manualWrap.cpp, but makes wrapping still a
> bit heavy on code.
>
> Do we use Matrix3r*Matrix3r somewhere?