Re: [Ublas] vector_view over (T*,size)

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Hi there,

yes, it is possible to do something like this. Please have a look at Vector
Proxies.
<https://www.boost.org/doc/libs/1_69_0/libs/numeric/ublas/doc/vector_proxy.html>


using namespace boost::numeric::ublas;
using vtype  = vector<double>;
using vrange = vector_range<vtype>;

auto v  = vtype(3);
auto r  = range(0,v.size()); // complete range
auto vr = vrange(v,r); // no copy of v


Best
CB





Am Mo., 21. Jan. 2019 um 11:28 Uhr schrieb dariomt--- via ublas <
[email protected]>:

> Hi list,
>
> Say I have a (GSL-like) span (which is basically a pointer and a length).
>
> Is it possible to build a vector-like view over that span, so that the
> result is usable within the ublas expression template machinery? Some kind
> of ublas::vector_view(T*, size)?
>
> The objective is to avoid having to copy all that data into a
> ublas::vector just to interoperate with other ublas code.
>
> Thanks in advance!
> _______________________________________________
> ublas mailing list
> [email protected]
> https://lists.boost.org/mailman/listinfo.cgi/ublas
> Sent to: [email protected]
>

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<div dir=3D"ltr"><div dir=3D"ltr"><div>Hi there,</div><div><br></div><div>y=
es, it is possible to do something like this. Please have a look at <a href=
=3D"https://www.boost.org/doc/libs/1_69_0/libs/numeric/ublas/doc/vector_pro=
xy.html">Vector Proxies.</a></div><div><br></div><div><br></div><div><pre>u=
sing namespace boost::numeric::ublas;<br>using vtype  =3D vector&lt;double&=
gt;;<br>using vrange =3D vector_range&lt;vtype&gt;;<br><br>auto v  =3D vtyp=
e(3); <br>auto r  =3D range(0,v.size()); // complete range<br>auto vr =3D v=
range(v,r); // no copy of v</pre></div><div><br></div><div>Best</div><div>C=
B<br></div><div><br></div><div><br></div><div><br></div><div><br></div></di=
v></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr=
">Am Mo., 21. Jan. 2019 um 11:28=C2=A0Uhr schrieb dariomt--- via ublas &lt;=
<a href=3D"mailto:[email protected]">[email protected]</a>&gt;:<br>=
</div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;b=
order-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr">Hi=
 list,<div><br></div><div>Say I have a (GSL-like) span (which is basically =
a pointer and a length).</div><div><br></div><div>Is it possible to build a=
 vector-like view over that span, so that the result is usable within the u=
blas expression template machinery? Some kind of ublas::vector_view(T*, siz=
e)?</div><div><br></div><div>The objective is to avoid having to copy all t=
hat data into a ublas::vector just to interoperate with other ublas code.</=
div><div><br></div><div>Thanks in advance!</div></div>
_______________________________________________<br>
ublas mailing list<br>
<a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]=
t.org</a><br>
<a href=3D"https://lists.boost.org/mailman/listinfo.cgi/ublas" rel=3D"noref=
errer" target=3D"_blank">https://lists.boost.org/mailman/listinfo.cgi/ublas=
</a><br>
Sent to: <a href=3D"mailto:[email protected]" target=3D"_blank">cem.bass=
[email protected]</a><br>
</blockquote></div>

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