Re: [ublas] scalar_vector doesn't support assignment of value types?

From: Robbie Vogt (r.vogt_at_[hidden])
Date: 2005-02-17 03:30:00

Is there much call for assigning to a scalar vector or matrix?  They
seem so light-weight that it is often best to work with temporaries.  I
find that helper functions help with this, i.e. something along the
lines,

template <typename _T>
scalar_vector<_T>
scalar (typename scalar_vector::size_type size, _T value)
{
  return scalar_vector<_T>(size,value);
}
template <typename _T>
scalar_matrix<_T>
scalar (typename scalar_matrix::size_type size1,
        typename scalar_matrix::size_type size2,
        _T value)
{
  return scalar_matrix<_T>(size1,size2,value);
}

so the compiler can work out the type implicitly for you and you can
just write

myVec += scalar(10, 1.0);
myMat = scalar(10,10, 0.1);

This also works for identity_matrix and zero_vector/matrix to a lesser
extent.  Pretty obvious, but maybe it helps someone...

Robbie.

Michael Stevens wrote:
> On Thursday 17 February 2005 08:01, Kresimir Fresl wrote:
> > Michael Stevens wrote:
> > > I think this is a good way to go. If you like the = syntax you can define
> > > 	operator= (scalar_vector<double> v, double s)
> > > 	{
> > > 		v = scalar_vector<double> (v.size(), s);
> > > 	}
> > > A good compiler should turn this into efficient code.
> > >     
> > Unfortunately, operator=() must be a member function.
> >
> > fres
> >   
>
> Blush Blush. It must have been late! That only leaves an ordinary named 
> function to do the job. Something like 'set' or 'set_scalar' would seem like 
> a nice name.
>
> Michael
> ___________________________________
> Michael Stevens Systems Engineering
>
> Navigation Systems, Estimation  and
>                  Bayesian Filtering
>     http://bayesclasses.sf.net
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