Re: [Freepooma-devel] A question about code for computation of Tensor determinant

[Richard Guenther]

ali rostai wrote:
> Hi,
> 
> In file "Tiny/TensorOperators.h" the following code has
> been used for computation of Tensor determinant.
> -------------------------------------------------
> // Partial specializations for D={1,2,3}
> template<class T, class E>
> inline T
> det(const Tensor<3,T,E>& t)
> {
>   T result;
>   result =
>     t(0,0)*(t(1,1)*t(2,2) - t(1,2)*t(2,1)) +
>     t(0,1)*(t(1,2)*t(2,0) - t(1,0)*t(2,2)) +
>     t(0,2)*(t(1,0)*t(2,1) - t(1,1)*t(2,0));
>   return result;
> }
> ---------------------------------------------------
> as I know the t(0,0) is a runtime call,
> why  the member function template "getIJ()" has not been
> used? I mean a code like this
> t.getIJ<0,0>()

It is because TensorOperators.h (and other Tiny classes) do not fully
use expression templates.  There is a patch on the patch-tracker
to fix this up for vectors (if I remember correctly) - the interaction
with the Array expression templates is complicated though.

It's an area that needs to be reworked a lot.

Richard.

> Regards
> Ali Roustaei
> 
> 
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