how model this problem?

[alessio211734]

Hello,
I should model a problem in c++.

I have a region compose by a set of points where every point have some property and a prev and next point.

start ->p1<->p2<->p3<->p4<->end

I would like split in more regions this points based on some nearby
property like curvature and high. I would like that in every region keep the adjacenty property of every point.


I tried to write some code:
I have some doubts about, what's happen if I delete some elements of shared list I think the iterator became invalid.
With a similar solution I need to sinchronyze every region when I delete an element and I should again understand what's happen on insert new element.

template <class T>
class SubRegion
{
public:
typedef typename std::list<T>::iterator ElementIterator;
typedef typename std::list<T>::const_iterator ConstElementIterator;
SubRegion(const std::list<ElementIterator> & lit)
{
pElements = lit;
};

typename std::list< ElementIterator >::iterator begin()
{
return pElements.begin();
};

typename std::list< ElementIterator >::iterator end()
{
return pElements.end();
};

T & element(typename std::list< ElementIterator >::iterator pelement)
{
return (*(*pelement));
};

std::list<ElementIterator> pElements;
};




template <class T>
class Region
{
public:
void buildRegions(std::list<T> & elements)
{
// suppose list with 3 element
shared_list = elements;
SubRegion<T>::ElementIterator it = elements.begin();
std::list<SubRegion<T>::ElementIterator> subElement1;
subElement1.push_back(it);
subRegion.push_back(subElement1);
std::list<SubRegion<T>::ElementIterator> subElement2;
subElement2.push_back(++it);
subElement2.push_back(++it);
SubRegion<T> r1(subElement1);
SubRegion<T> r2(subElement2);
subRegion.push_back(r1);
subRegion.push_back(r2);
//SubRegion<T> s1
}
SubRegion<T> & getRegion(int i)
{
return subRegion[i];
}
protected:
std::vector< SubRegion<T> > subRegion;
std::list<T> shared_list;
};

[Jorgen Grahn]

On Tue, 2018-03-27, alessio211734 wrote:
> Hello,
> I should model a problem in c++.
>
> I have a region compose by a set of points where every point have
> some property and a prev and next point.
>
> start ->p1<->p2<->p3<->p4<->end

Are you simply trying to say you have a polygon defined by its
verticises? And that each vertex has a property?

> I would like split in more regions this points based on some nearby
> property like curvature and high. I would like that in every region
> keep the adjacenty property of every point.

I can't guess what this means. Perhaps it's not a polygon, but then I
don't know what it is. Also "based on some nearby property" sounds
very vague.

You'd get better help if you could clarify the problem a bit more.

/Jorgen

--
// Jorgen Grahn <grahn@ Oo o. . .
\X/ snipabacken.se> O o .

[alessio211734]

it's a 2d section composed by 2d vertex. The section is a list of 2d vertex order in ccw way. I should divide the initial region(the initial section) in more regions based on the curvature and other property
To calculate this region I should know the adjacent vertex of every vertex.
Maybe after I divide in subregion I need to merge some region together.

[Jorgen Grahn]

On Tue, 2018-03-27, alessio211734 wrote:
> Il giorno martedì 27 marzo 2018 13:08:54 UTC+2, Jorgen Grahn ha scritto:
>> On Tue, 2018-03-27, alessio211734 wrote:
>> > Hello,
>> > I should model a problem in c++.
>> >
>> > I have a region compose by a set of points where every point have
>> > some property and a prev and next point.
>> >
>> > start ->p1<->p2<->p3<->p4<->end
>>
>> Are you simply trying to say you have a polygon defined by its
>> verticises? And that each vertex has a property?
>>
>> > I would like split in more regions this points based on some nearby
>> > property like curvature and high. I would like that in every region
>> > keep the adjacenty property of every point.
>>
>> I can't guess what this means. Perhaps it's not a polygon, but then I
>> don't know what it is. Also "based on some nearby property" sounds
>> very vague.
>>
>> You'd get better help if you could clarify the problem a bit more.
>>
>> /Jorgen
>

> it's a 2d section composed by 2d vertex. The section is a list of 2d
> vertex order in ccw way. I should divide the initial region(the
> initial section) in more regions based on the curvature and other
> property To calculate this region I should know the adjacent vertex
> of every vertex. Maybe after I divide in subregion I need to merge
> some region together.

I still don't understand if this is a polygon or not, but perhaps
someone else does and can answer. Good luck!

[Öö Tiib]

On Tuesday, 27 March 2018 15:31:14 UTC+3, Jorgen Grahn wrote:
>
> I still don't understand if this is a polygon or not, but perhaps
> someone else does and can answer. Good luck!

What he described sounded to me like what is in computer graphics
called "polyline" (not "polygon"). I may be wrong because I also did
not understand his question.