Re: [Toon-members] std::vector overload to use with TooN ( Dynamic Matrix assembling)

[Gerhard Reitmayr]

how about a Resizable matrix and a slice after it has been assembled ? you 
would have to keep it around between iterations to avoid memory reallocation. 
but it would be as efficient as a std::vector which also will reallocate and 
copy the contents, if new elements are added and it exceeds the reserved size.

another way would be to take the std::vector contents and wrap with a matrix 
using wrapMatrix (see internal/reference.hh). std::vector stores data in one 
memory block so that should work fine.

cheers,
  Gerhard


On 22 May 2010, at 12:24, Gabriel Nützi wrote:

> Hello all
> 
> 
> I have a question , and I don't know how to solve this as good as possible:
> 
> I have an iteration in which I always assemble new Matrices (m x 7)  
> dynamically, so I do not know how big they become in each iteration, the size 
> m varies, 
> 
> Is there a way of realizing this either with TooN or with overloads in 
> std::vector< Vector<7> >   efficiently
> The only way I can push rows in my Matrix dynamically is with std::vector ....
> 
> I was searching for a way to make this compatible with TooN and efficient (I 
> dont want to copy heaps of data around) ? But I ve come up so far only with a 
> overload in std::vectors
> 
> wrote the  fallowing overload:
> 
> 
> //Specialized Template vor Vector<>
> template <int N1, int N2, typename P, typename B>
> Vector<Dynamic,P,B> operator*(const std::vector<Vector<N1,P,B> >& x, 
> Vector<N2,P,B> &y)
> {
>     Vector<Dynamic,P,B> v(x.size());
>       v= Zeros;
>       for (int m=0; m< x.size();m++) {
>               for (int n=0; n<y.size(); n++) {
>                       v[m] += x[m][n] * y[n];
>               }
>       }
>       return v;
> }
> 
> 
> 
> Does anyone know why the error happens here: 
> 
>       vector<Vector<3> > A;
>       A.assign(3,makeVector(1,2,3));
>       Vector<> a = makeVector(2,2,2);
>       
>       Vector<> c = A * a ;
>       Vector<> b = A * ( A * a );   // ERRRRROOOOOORRRRRR  (but why))
> 
> 
> Would be very helpful if anyone could tell me how I should do this to make it 
> efficient , and why this ERROR happens?
> 
> 
> Thanks alot for your support!
> 
> Gabriel
> 
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--
Gerhard Reitmayr
Institute for Computer Graphics and Vision
http://www.icg.tugraz.at/Members/gerhard
tel: ++43 316 873 5082