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Ublas : |
From: erwann rogard (erwann.rogard_at_[hidden])
Date: 2007-09-05 09:48:04
thanks. i would think too that subrange as a copy is less efficient.
On 8/7/07, e r <erwann.rogard_at_[hidden]> wrote:
>
> hi,
>
> it appears that subrange of a const vector& will achieve read--only
>
> subrange(copy, 0,1);//where copy is a const vector&
>
> however, i am unable to assign it i.e. it is a temporary object so that
> in comparing
>
> 1. call subrange(copy,0,1) N times
> VS.
> 2. a) create vr1(orig,range(0,1)) and b) call vr1 N times //where orig
> is -unfortunately- not a const
>
> i would think that 1. allocates some memory each time it is called
> whereas 2. does not, hence is 1. slower. correct?
>
> e r wrote:
> > hi all,
> >
> > i'm wondering how/if i can create vector proxies of a const vector e.g.
> >
> > typedef boost::numeric::ublas::vector<double> vector_double;
> > typedef boost::numeric::ublas::range range;
> > typedef boost::numeric::ublas::vector_range<vector_double >
> vector_range;
> >
> > vector_double orig(6);
> > const vector_double& copy = orig;
> > vector_range vr1(orig,range(0,1));
> > vector_range vr2(copy,range(0,1));//error: no matching function
> >
> >
> > thanks much!
> >
> > e.
> >
>
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