Hi list
Thanks for response . i am sending some attachments and my confusions.
1) While running sum_by_decomposition (attached in mail ) under examples Minkowski_sum_2 and p4.dat (attached in mail) as input file for polygons. i got floating point exception as follows :
[root@localhost Minkowski_sum_2]# ./sum_by_decomposition p4.dat
Floating point exception
the same happens on running sum_with_holes
[root@localhost Minkowski_sum_2]# ./sum_with_holes p4.dat
Floating point exception
[root@localhost Minkowski_sum_2]#
2) I am attaching the file approx_offset.cpp . In order to print general polygon which would represent the Minkowski sum of a circle of given radius ,under given error bound,with a given polygon.
when i try for it in example Minkowski_sum_2 under my attahed files approx_offset.cpp and print_utils.h . i got following output
[root@localhost Minkowski_sum_2]# ./approx_offset
USAGE:executablename inputfilename radius errorbound [root@localhost Minkowski_sum_2]# ./approx_offset spiked.dat 5 0.00001 CGAL error: precondition violation! Expr: CGAL::sign (eps) == POSITIVE File: /usr/include/CGAL/Minkowski_sum_2/Approx_offset_base_2.h Line: 83 Explanation: terminate called after throwing an instance of 'CGAL::Precondition_exception' what(): CGAL ERROR: precondition violation! Expr:
CGAL::sign (eps) == POSITIVE File: /usr/include/CGAL/Minkowski_sum_2/Approx_offset_base_2.h Line: 83 Aborted [root@localhost Minkowski_sum_2]#
plz make some light to get print of general polygon which would represent the Minkowski sum of a circle of given radius ,under given error bound,with a given polygon.
Thanks alot
AMIT TRIPATHI 09836562804 M.Tech(C.S.) I.S.I. KOLKATA
--- On **Tue, 6/17/08, [hidden email] ***<[hidden email]>* wrote:
From: [hidden email] <[hidden email]> Subject: Re: [cgal-discuss] Minkowski'sum : offsetting a polygon To: [hidden email] Date: Tuesday, June 17, 2008, 3:51 PM
I have to admit that a more extensive example would help here, and we do consider enhancing the existing one for the next release. In the mean time, the offset polygon is an object of type Traits::General_polygon_with_holes_2, which models the concept GeneralPolygonWithHoles_2 <http://www.cgal.org/Manual/3.3/doc_html/cgal_manual/Boolean_set_operations_2_ref/Concept_GeneralPolygonWithHoles_2.html#Cross_link_anchor_726>. Consult the manual for the relevant valid expressions involving a model of
this concept. In short you can obtain the outer boundary of type Traits::Polygon_2, and traverse the holes to obtain objects of the same type. You can obtain the curves that comprise the boundaries of these objects using the traits function-object Traits::Construct_curves_2.
The regularized intersection of 2 polygons that share a vertex or an edge is empty. In other words they do not intersect. However you are not suppose to get a floating point exception under any circumstances (assuming you use exact arithmetic, etc). If you do, it might be a bug, and we would like to get a short test case that reproduces it.
Quoting "amit tripathi" <[hidden email]>:
> > > Hi list..... >
> i am learning/using CGAL ........by examples given in library...........i have following > questions ........... > > 1) how to find output of Minkowski sum of a cicle of given radius > and a simple polygon.............in examples ...offsetting > polygon......it is not given that how to get print of > offset...................i dont know how this object is stored..... > > > > 2) Boolean operations supported by CGAL are regular so > > > when I was designing test cases for polygon intersection code > …………I found that code has some problem in the execution for > the
cases… > 1) P int Q ={(x,y)} > 2) P int Q ={(x,y) : y=mx+c} > 3) P int Q = null > > > But when I put check for the case P int Q =null …..then for the > three cases I got corresponding outputs as follows…… > 1) Floating point exception > 2) Do not intersect > 3) Do not intersect > > Which is not consistent….to situation ……… > > Is there any way to get ordinary intersection that can resolve above >
problems...............the problem may be solved if we know how > polygons are stored then check for same vertices in both the > polygons....... > > Even if i am trying to find the Minkowski sum of P and Q > (as described in Minkowski_sum_2) .............i faced problem for > the above three cases.......................... > > > plz try to help me ............my assignment submission date is near.... > > thanks for all........ > > > > AMIT TRIPATHI > 09836562804 > M.Tech(C.S.) > I.S.I. KOLKATA > > > -- > You are currently subscribed to cgal-discuss. > To unsubscribe or access the archives, go to > https://lists-sop.inria.fr/wws/info/cgal-discuss >
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