From thouis at graphics.lcs.mit.edu Fri Feb 7 12:49:23 2003 From: thouis at graphics.lcs.mit.edu (Ray Jones) Date: Mon Jan 9 13:41:08 2006 Subject: 3D sphere tangent to four triangles Message-ID: I'm looking for a discussion (or decipherable code) for finding the set of spheres tangent to four triangles. I imagine the straightforward way to do this is to iterate over the corners (points), edges (lines), and interior (plane) and find a sphere tangent to four such elements, one from each triangle. But I haven't found a description of the solution to this subproblem, either. Ray Jones ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From ungor at cs.duke.edu Sat Feb 8 13:09:39 2003 From: ungor at cs.duke.edu (Alper Ungor) Date: Mon Jan 9 13:41:08 2006 Subject: 12th IMR: First Call for Papers Message-ID: 12th International Meshing Roundtable Call for Papers Due Date: Full paper due May 1, 2003 Website: http://www.imr.sandia.gov Technical Contacts: Alper ?ng?r (ungor@cs.duke.edu), Paul Chew (chew@cs.cornell.edu) and John Steinbrenner (jps@pointwise.com) ***************************************** Join us for the 12th International Meshing Roundtable to be held in Santa Fe, New Mexico, September 14-17, 2003. In 1992, Sandia National Laboratories started the Meshing Roundtable as a small meeting of like-minded companies and organizations striving to establish a common focus for research and development in the field of mesh and grid generation. Sandia National Laboratories continues to organize the International Meshing Roundtable, which has become recognized as an international focal point annually attended by researchers and developers from dozens of countries around the world. The International Meshing Roundtable continues to focus on bringing together researchers and developers from academia, national labs and industry in a stimulating, open environment to share technical information related to mesh generation and general pre-processing techniques. In 2003, Roundtable attendees will enjoy Santa Fe's unique southwest architecture, picturesque streets, Loretto Chapel and miraculous staircase, distinctive regional foods, fine museums and art galleries. Santa Fe is filled with 400 years of history and culture. The conference hotel, Inn at Loretto, is within walking distance to the plaza, Palace of the Governors and other attractions. EVENTS ---------- Events at this year's roundtable include: * Pre-conference short course on Sunday, September 14 * Technical presentations of contributed papers * Keynote and invited speakers * Poster session with Best Technical Poster, Best Student Poster and Meshing Maestro awards. We encourage submission of posters presenting novel research results as well as posters showcasing state-of-the-art technology by industry developers and meshing software vendors * Birds-of-a-Feather session providing a discussion forum for small groups of researchers working in similar fields * Panel discussion * Dinner banquet More information on the Roundtable, as it becomes available, will be published at the International Meshing Roundtable website: http://www.imr.sandia.gov IMPORTANT DATES ------------------------ May 1, 2003 Full paper due July 1, 2003 Acceptance/Rejection notices sent to authors August 1, 2003 Final camera-ready papers due August 13, 2003 Early conference registration due August 13, 2003 Hotel reservation due for special discount rates September 14, 2003 Short Courses, Inn at Loretto, Santa Fe, New Mexico September 15-17, 2003 12th International Meshing Roundtable, Inn at Loretto, Santa Fe, New Mexico, USA CALL FOR PAPERS ----------------------- Papers are being sought that present original results on meshing and related topics. We encourage theoretical and novel ideas with practical potential as well as technical applications from industrial researchers. In addition to our core topics in meshing related algorithms, we are also interested in obtaining technical papers that relate analysis and application solutions to the mesh generation process. Potential topics include but are not limited to: * Adaptive meshing * Anisotropic mesh generation * CAD interface for meshing * Geometry simplification, decomposition, and cleanup * Tetrahedral/Hexahedral/Hybrid meshing * Industrial applications for complex geometries * Mesh data formats and databases * Mesh quality, smoothing, and optimization * Mesh simplification and compression * Meshing of parametric models * Parallel meshing algorithms and software * Scientific visualization * Structured and unstructured grid generation * Surface reconstruction * Theoretical basis of mesh generation * Volume and surface mesh generation PROCEEDINGS AND JOURNAL SPECIAL ISSUE -------------------------------------------------------- The conference proceedings will be published by Sandia National Laboratories and distributed at the roundtable. Selected high-quality papers will be invited in a special issue of an engineering or computer science journal. PAPER SUBMISSIONS -------------------------- Papers should contain significant technical content to be accepted. No presentation will be permitted at the conference without the submission and acceptance of a technical paper. Accepted papers will be published in the proceedings and will also be available on CD. Pending author approval they may be available on the IMR website. The proceedings are printed in black and white. Papers should be 8-12 pages in length (9 point, two columns) and received by May 1, 2003. Formatting details including templates for Word and LaTeX will be available on the conference web site. Final camera-ready papers not meeting formatting guidelines will not be accepted for publication in the proceedings. Paper submissions will be accepted in Word and PostScript, electronic submission only. Papers can be transferred by anonymous ftp to endo.sandia.gov (place in directory pub/incoming/jfsheph/12imr) or can be mailed to ungor@cs.duke.edu. Files transferred via anonymous ftp should be named as follows, to avoid collisions on the ftp site: names should start with the first author's last name, followed by a hyphen, followed by the last four digits of the author's phone number. Authors should send email to Alper ?ng?r, (ungor@cs.duke.edu) with the paper title and file name immediately after placing it on the site. Questions regarding paper submission should be addressed to Alper ?ng?r, John Steinbrenner or Paul Chew, Technical Papers Co-Chairs. CONFERENCE REGISTRATION ------------------------------------- A detailed registration form will be made available on the International Meshing Roundtable website at: http://www.imr.sandia.gov CONFERENCE LOCATION AND HOTEL RESERVATIONS ------------------------------------------------------------------- The site of this year's roundtable is the city of Santa Fe, New Mexico. The Roundtable will be held at the Inn at Loretto located in 1 block from the Santa Fe Plaza and has 135 guestrooms and 5 suites. Parking your car at the hotel will cost an additional $14.00 per car, per night. The Inn at Loretto is just 20 minutes from the Santa Fe Municipal Airport and one-hour from the Albuquerque Airport. Please check the web site at http://www.imr.sandia.gov for detailed instructions on getting to Santa Fe from the above locations and other transportation options. The Inn at Loretto 211 Old Santa Fe Trail Santa Fe, New Mexico 87501 1-505-988-5531 (Direct) 1-505-984-7988 (Fax Number) 1-800-727-5531 (Toll-free Number) http://www.hotelloretto.com A block of rooms has been reserved at the Inn at Loretto at a special conference rate of $99.00 single/$119.00 double, plus state and local taxes. Reservations must be made directly to the Inn at Loretto on an individual basis. In order to facilitate reservations, attendees must dial the hotel directly and request the Reservations Department. It is imperative that individuals indicate their group affiliation (12th International Meshing Roundtable) when making reservations. To ensure obtaining this rate, participants must make their own reservations before August 13th, 2003. Please note that September is an extremely busy time of the year in Santa Fe and hotel rooms are at a premium. Therefore, make your hotel reservations early or the price of a room could very well double in cost. As a special consideration to the 12th Meshing Roundtable attendees the Inn at Loretto has extended these same room rates for up to 3 days pre and post stays, based on room type and applicable rate availability. STEERING COMMITTEE ---------------------------- The International Meshing Roundtable Steering Committee consists of representatives from national research labs, academia, and industry who serve on a rotating basis. This year's committee is: Jason Shepherd, Committee Chairman, Short courses and Panel discussions Sandia National Laboratories Phone: 505-284-6600 Fax: 505-844-9297 E-mail: jfsheph@sandia.gov FTP: endo.sandia.gov (pub/incoming/jfsheph/12imr) Alper ?ng?r, Technical Papers Co-Chair Duke University Phone: 919-660-6558 Fax: 919-660-6519 E-mail: ungor@cs.duke.edu Paul Chew, Technical Papers Co-Chair Cornell University Phone: 607-255-9217 Fax: 607-255-4428 Email: chew@cs.cornell.edu John Steinbrenner, Technical Papers Co-Chair and Panel discussions Pointwise, Inc. Phone: 817-377-2807 ext.106 Fax: 817-377-2799 E-mail: jps@pointwise.com Eric Hjelmfelt, Co-Chair for Industry, BOF and Posters Altair Engineering Phone: 248-614-2400 Fax: 248-614-2411 E-mail: eeh@altair.com Jamshid Samareh, Co-Chair for Government, BOF and Short courses NASA Langley Phone: 757-864-5776 Fax: 757-864-9713 Email: j.a.samareh@larc.nasa.gov ADDITIONAL CONTACTS ------------------------------- Anita Vasey, Conference Coordinator Sandia National Laboratories Phone: 505-844-1338 Fax: 505-844-2415 E-mail: arvasey@sandia.gov Bernadette Watts, Financial Coordinator and Webmaster Sandia National Laboratories Phone: 505-844-3936 Fax: 505-844-2415 E-mail bmwatts@sandia.gov ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From fsttcs at tifr.res.in Thu Feb 13 23:50:24 2003 From: fsttcs at tifr.res.in (FSTTCS) Date: Mon Jan 9 13:41:08 2006 Subject: FSTTCS'03 First Call for Papers (postscript version is attached) Message-ID: [Our apologies if you receive this more than once.] ====================================================================== CALL FOR PAPERS 23rd conference on FOUNDATIONS OF SOFTWARE TECHNOLOGY AND THEORETICAL COMPUTER SCIENCE (FSTTCS '03) December 15--17, 2003 Indian Institute of Technology, Bombay, India ===================================================================== The Indian Association for Research in Computing Science, IARCS, announces the 23nd Annual FSTTCS Conference in Mumbai. The FSTTCS conference is a forum for presenting original results in foundational aspects of Computer Science and Software Technology. The conference proceedings are published by Springer-Verlag as Lecture Notes in Computer Science (LNCS). Authors are invited to submit papers presenting original and unpublished research in any area of Theoretical Computer Science or Foundational aspects of Software Technology. Representative areas include, but are not limited to: Automata, Languages and Computability Automated Reasoning, Rewrite Systems, and Applications Combinatorial Optimization Computational Geometry Computational Biology Complexity Theory Concurrency Theory Cryptography and Security Protocols Database Theory and Information Retrieval Data Structures Graph and Network Algorithms Implementation of Algorithms Logic, Proof Theory, Model Theory and Applications Logics of Programs and Temporal Logics New Models of Computation Parallel and Distributed Computing Programming language design Randomized and Approximation Algorithms Real-time and Hybrid Systems Semantics of Programming Languages Software Specification and Verification Static Analysis and Type Systems Theory of Functional and Constraint-based Programming In addition, there will be workshops at IIT Bombay following FSTTCS'03 on some current areas of research (topics to be announced on the conference web page). The following two conferences on related areas will be also be held in Mumbai between 9 and 13 December 2003: International Conference on Logic Programming (ICLP'03) and ASIAN'03. Submission Guidelines ===================== Authors may submit drafts of full papers or extended abstracts. Submissions are limited to 12 pages in LNCS style (see the conference site for full details). Proofs omitted due to space constraints may be put into a clearly marked appendix. Electronic submission is very strongly recommended. For details, please look at the conference site: http://www.fsttcs.org For an accepted paper to be included in the proceedings, one of the authors must commit to presenting the paper at the conference. Important Dates =============== Submission deadline: 1 July 2003 Notification: 15 August 2003 Final Version due: 15 September 2003 Conference Site: http://www.fsttcs.org/ ================ Program Committee: ================== R Alur (University of Pennsylvania) V Arvind (IMSc, Chennai) M Charikar (Princeton University) T Dey (Ohio State University) J Esparza (University of Stuttgart) S Ghosh (TIFR, Mumbai) M Halldorsson (University of Iceland) J Radhakrishnan (TIFR, Mumbai, co-chair) H Karloff (AT&T Labs--Research) K Lodaya (IMSc, Chennai) PB Miltersen (BRICS, Aarhus) J Mitchell (Stanford) P O'Hearn (Queen Mary, London) PK Pandya (TIFR, Mumbai, co-chair) S Prasad (IIT Delhi) SK Rajamani (Microsoft research, Redmond) S Sen (IIT Delhi) D Sivakumar (IBM, Almaden) G Sivakumar (IIT Bombay) Th Wilke (University of Kiel) U Zwick (Tel Aviv University) Communication: ============== Attn: FSTTCS School of Technology and Computer Science Tata Institute of Fundamental Research Mumbai 400 005 India fsttcs@tifr.res.in Phone: +91 22 2215 2971 Fax: +91 22 2215 2110 -------------- next part -------------- A non-text attachment was scrubbed... Name: cfp.ps Type: application/postscript Size: 17871 bytes Desc: Postcript Version of Call for Papers Url : http://compgeom.poly.edu/pipermail/compgeom-announce/attachments/20030213/c95f8cc8/cfp.ps From Jean-Daniel.Boissonnat at sophia.inria.fr Tue Feb 11 11:50:31 2003 From: Jean-Daniel.Boissonnat at sophia.inria.fr (Jean-Daniel Boissonnat) Date: Mon Jan 9 13:41:08 2006 Subject: Postdoctoral Position at IFP Message-ID: <200302111050.h1BAoVIr001586@dubhe.inria.fr> Subject: Hybrid Grid generation for reservoir fluid flow simulation Located 10kms (6miles) from Paris, the Institut Fran?ais du P?trole (IFP) is a French industrial research, education, and information center active in the fields of oil, natural gas, and automobiles. The mission of the IFP is to develop innovative technologies that will allow sustainable growth of the hydrocarbon and automobile industries and preserve the environment. Research and Development (R&D) at the IFP is applied and by vocation, covering every technical field related to oil and natural gas, their derivatives and substitutes: exploration, drilling, production, refining, petrochemicals, internal combustion engines and the rational use of energy, together with the associated aspects of environmental protection. This applied research is however backed up by substantial fundamental research which is vital for the continued development of the IFP's scientific assets, and consequently, of its long term future (for more information about IFP see http://www.ifp.fr ). The proposed work is related to a research program held at the IFP on multiphase fluid flow simulation in porous media aiming to optimise reservoir oil production. Grid generation and management is a key step in such kinds of simulation. Recently the IFP has proposed an original hybrid grid modelling methodology for more accurate reservoir simulation. This approach has been successfully developed and tested in the 2.5D case. The retained candidate will join an active research team in charge of the extension of this hybrid modelling into full 3D, with tests and validation. More specifically he/she will be involved with the geometrical aspects of this 3D extension related to grid generation and management. The applicant should have a recent Ph. D. and some experience working with grid generation and/or computational geometry and should be familiar with programming in C++ and the Unix environment. The salary will be of about 2200 Euros/month. The duration is from 12 to 18 months, starting as soon as possible. For application or more information please contact and/or send your resume to: Chakib Bennis 1 & 4, avenue de Bois-Pr?au 92852 Rueil-Malmaison France Phone: +33 1 47 52 71 31 Fax: +33 1 47 52 70 22 E-mail: Chakib.Bennis@ifp.fr - ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From michiel at scs.carleton.ca Mon Feb 10 08:35:25 2003 From: michiel at scs.carleton.ca (Michiel Smid) Date: Mon Jan 9 13:41:08 2006 Subject: WADS: final call for papers Message-ID: <3E47AA9D.A050CF03@scs.carleton.ca> -------------- next part -------------- Final Call For Papers Workshop on Algorithms and Data Structures (WADS) July 30 - August 1, 2003 Ottawa, Canada Submission deadline: February 20, 2003 The Workshop, which alternates with the Scandinavian Workshop on Algorithm Theory, is intended as a forum for researchers in the area of design and analysis of algorithms and data structures. We invite submissions of papers presenting original research on the theory and application of algorithms and data structures in all areas, including combinatorics, computational geometry, databases, graphics, parallel and distributed computing. Contributors are invited to submit a full paper (not exceeding 12 pages). Detailed submission instructions are located at http://www.wads.org. Submissions must arrive on or before Feb. 20 at 12:00 noon EST. Authors will be notified of acceptance or rejection by April 21, 2003. Proceedings will be published in the Springer Verlag series Lecture Notes in Computer Science. The final versions of accepted papers must arrive in camera-ready form before May 12, 2003 to ensure the availability of the proceedings at the conference. Selected papers will be invited for publication in a special issue of Computational Geometry: Theory and Applications. Invited Speakers: Gilles Brassard, Daniel Spielman, Dorothea Wagner. Special Presentation: Wing T. Yan (Nelligan O'Brien Payne LLP, www.nelligan.ca), "Protecting your intellectual property". Pre-WADS Special Event: one-day tutorial on "Neural Networks in System Identification and Forecasting: Principles, Techniques, Applications" by Georg Zimmermann, Siemens AG, Muenchen Post-WADS Special Event: one-day workshop on Fixed Parameter Tractability (FPT) Conference Chair: Michiel Smid Program Committee: Co-Chairs: F. Dehne, J.-R. Sack, M. Smid. PC-Members: Lars Arge (Duke) Susanne Albers (Freiburg) Michael Atkinson (Dunedin) Hans Bodlaender (Utrecht) Gerth Brodal (Aarhus) Tom Cormen (Dartmouth) Timothy Chan (Waterloo) Erik Demaine (MIT) Mike Fellows (Newcastle) Pierre Freigniaud (Paris-Sud) Naveen Garg (Delhi) Andrew Goldberg (Microsoft) Giuseppe Italiano (Rome) Ravi Janardan (Minneapolis) Rolf Klein (Bonn) Stephan Naeher (Trier) Giri Narasimhan (Florida International University) Rolf Niedermeier (Tuebingen) Viktor Prasanna (Southern California) Andrew Rau-Chaplin (Halifax) R. Ravi (Carnegie Mellon) Paul Spirakis (Patras) Roberto Tamassia (Brown) Jeff Vitter (Purdue) Dorothea Wagner (Konstanz) Peter Widmayer (Zurich) From Bhautik.Joshi at csiro.au Sat Feb 15 13:08:41 2003 From: Bhautik.Joshi at csiro.au (Joshi, Bhautik (CTIP, Marsfield)) Date: Mon Jan 9 13:41:08 2006 Subject: constrained/conforming tetrahedrization algorithms - bounds on Steiner point insertion In-Reply-To: <009201c29920$5d378cc0$1400a8c0@pc2> Message-ID: Hi, I have recently been trying to establish the current state-of-the art in constrained/conforming tetrahedrization algorithms. One thing that I have not been able to establish clearly is the current lowest upper bound for the number of steiner points inserted into a mesh for a conforming (or, if the Delaunay requirements are relaxed, a constrained) triangulation. In two dimensions, it seems that that bound has been farily well established, but in three it seems a little unclear. I have been able to find a couple of papers that establish a bound that is 'too much for practical use' - would anybody out there be able to point me at any recent publications that could better establish that bound? Cheers, Bhautik ---------------------------------------- Bhautik Joshi PhD Student, UNSW/CSIRO Australia http://cow.mooh.org ---------------------------------------- ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From Nie at asu.edu Thu Feb 13 19:10:06 2003 From: Nie at asu.edu (Nie@asu.edu) Date: Mon Jan 9 13:41:09 2006 Subject: Announcing BibFinder: a bibliography search engine for your use Message-ID: Dear all, You can now use the BibFinder tool to get information on all sorts of information about CS papers. check out http://rakaposhi.eas.asu.edu/bibfinder BibFinder is a free computer science bibliography search engine. It integrates CSB, DBLP, ACM Digital Library, ScienceDirect, CiteSeer, and Google. These sources are partially overlapping both in tuples and attributes. For example, some sources may have bibtex for a paper, some may have pdf file for the paper, some may have abstract. By combining them, present a unified andmore complete view to the user. More detailed information about BibFinder is available at http://kilimanjaro.eas.asu.edu/about.html If you want to put a link on your homepage to get a collated list of your publications, you can do so with the following link: http://kilimanjaro.eas.asu.edu/servlets/Search?author=your_firstname+your_lastname (or any other query which can identify your publications). If you have any suggestions, please send them to nie@asu.edu Best, Nie --------------- Zaiqing Nie CSE, ASU ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From edemaine at mit.edu Tue Feb 25 09:09:23 2003 From: edemaine at mit.edu (Erik Demaine) Date: Mon Jan 9 13:41:09 2006 Subject: Videos Accepted to SoCG 2003 Message-ID: 12th Annual Video Review of Computational Geometry, part of the 19th ACM Symposium on Computational Geometry, June 8-10, 2003, San Diego, USA http://www.cs.umd.edu/areas/Theory/socg03/ List of Accepted Videos ======================= 1. Curves of Bounded Width and the Asteroid Surveying Problem Timothy Chan and Alexander Golynski and Alejandro L?pez-Ortiz 2. VASCO: Visualizing and Animating Spatial Constructs and Operations Frantisek Brabec and Hanen Samet and Cemal Yilmaz 3. Billboard Clouds for Extreme Model Simplification Xavier D?coret and Fr?do Durand and Fran?ois Sillion and Julie Dorsey 4. Morphing between Shapes by Using their Straight Skeletons Gill Barequet and Evgeny Yakersberg 5. A 3-D Visualization of Kirkpatrick's Planar Point Location John Iacono 6. 3DTreeDraw: A Three Dimensional Tree Drawing System Tom Murtagh and Seok-Hee Hong 7. Online Dispersion Algorithms for Swarms of Robots Tien-Ruey Hsiang and Esther M. Arkin and Michael A. Bender and S?ndor P. Fekete and Joseph S. B. Mitchell 8. Finding a Curve in a Map Carola Wenk and Helmut Alt and Alon Efrat and Lingeshwaran Palaniappan and G?nter Rote 9. Fast Penetration Depth Estimation Using Rasterization Hardware and Hierarchical Refinement Young J. Kim and Miguel A. Otaduy and Ming C. Lin and Dinesh Manocha Erik -- Erik Demaine | edemaine@mit.edu | http://theory.lcs.mit.edu/~edemaine/ ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From marco.pellegrini at iit.cnr.it Mon Feb 24 16:43:06 2003 From: marco.pellegrini at iit.cnr.it (Marco Pellegrini) Date: Mon Jan 9 13:41:09 2006 Subject: Postdoc and Predoc positions in Pisa - Italy Message-ID: <5.1.0.14.0.20030224164253.0236f090@pop.iat.cnr.it> Skipped content of type multipart/alternative-------------- next part -------------- A non-text attachment was scrubbed... Name: bando_02_2003_en.pdf Type: application/pdf Size: 144408 bytes Desc: not available Url : http://compgeom.poly.edu/pipermail/compgeom-announce/attachments/20030224/fc99dd5a/bando_02_2003_en.pdf -------------- next part -------------- A non-text attachment was scrubbed... Name: bando_03_2003_en.pdf Type: application/pdf Size: 152706 bytes Desc: not available Url : http://compgeom.poly.edu/pipermail/compgeom-announce/attachments/20030224/fc99dd5a/bando_03_2003_en.pdf From efowler at seanet.com Mon Feb 24 20:01:47 2003 From: efowler at seanet.com (Eric Fowler) Date: Mon Jan 9 13:41:09 2006 Subject: Need STL implementation of computational geometry problem Message-ID: I am working on a simple sweepline algo from Computational Geometry, de Berg, van Kreveld et.al., 2nd Editon, Section 1.2. The basic idea is to find intersections among a set of line segments by sweeping a line down and testing at event points, which are segment endpoints (given) and intersections (discovered as you go). It is implicit in the problem that you need to be able to find line segments directly "adjacent" to a given event point. "Adjacent" means if you draw a horizontal sweepline through that point, the "adjacent" segments are the ones on either side of the point (if they exist) which intersect the line, and are closest to the point. You can have at most two, one "smaller" (left of) and one "larger" (right of) the point. Of course, colinearity is adjacency also. So, we have a little problem of ordering segments .... The book has a type of binary tree structure and expects us to handroll an implementation - not too hard - but I am anal about using STL as much as I can. So, I want an STL-ish way to do this. In general, I would like to extend the set or map template classes to do something like this: collection_type coll; //populate c with segments ... Point point_on_sweepline(x_coord, y_coord); LineSegment * pS = coll.find_adjacent_upper(point_on_sweepline); // use pS for something ... blah ... pS = coll.find_adjacent_lower(point_on_sweepline); etc. I am looking for suggestions leading to a CLEAN implementation. I have tried defining classes as sorting criteria, with operator(), but it wants two operands of the same type. I need to use a Point& to fish for a LineSegment*, so that does not work ... Any ideas? Eric ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From berti at ccrl-nece.de Wed Feb 26 09:29:30 2003 From: berti at ccrl-nece.de (Guntram Berti) Date: Mon Jan 9 13:41:09 2006 Subject: Need STL implementation of computational geometry problem In-Reply-To: ; from efowler@seanet.com on Mon, Feb 24, 2003 at 08:01:47PM -0800 References: Message-ID: <20030226092930.L2450@Kirchhoff.ccrl-nece.de> Hi Eric, > So, we have a little problem of ordering segments .... > The book has a type of binary tree structure and expects us to handroll an > implementation - not too hard - but I am anal about using STL as much as I > can. So, I want an STL-ish way to do this. In general, I would like to > extend the set or map template classes to do something like this: > > collection_type handrolled_sorting_criteria_or_algorithm_or_something> coll; > > //populate c with segments ... > > Point point_on_sweepline(x_coord, y_coord); > > LineSegment * pS = coll.find_adjacent_upper(point_on_sweepline); > > // use pS for something ... blah ... > > pS = coll.find_adjacent_lower(point_on_sweepline); > > etc. > > I am looking for suggestions leading to a CLEAN implementation. > > I have tried defining classes as sorting criteria, with operator(), but it > wants two operands of the same type. I need to use a Point& to fish for a > LineSegment*, so that does not work ... Couldn't you just do: LineSegment Lp(Point(x+epsilon, y), Point(x-epsilon,y)); coll_type::iterator pS_after = coll.upper_bound(Lp); // ... coll_type::iterator pS_before = --pS_after; HTH --guntram -- ============================================================ Guntram Berti -- NEC C&C Research Labs O__ == Rathausallee 10, D-53757 St. Augustin, Germany c/ /'_ == ++49 +2241 92 52 -32(voice) -99(fax) (*) \(*) == ------------ http://www.ccrl-nece.de/~berti - berti@ccrl-nece.de ============================================================ ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From qinsc at comp.nus.edu.sg Fri Feb 28 11:54:33 2003 From: qinsc at comp.nus.edu.sg (Shengchao Qin) Date: Mon Jan 9 13:41:09 2006 Subject: Call For Papers - ICFEM2003 in Singapore Message-ID: Skipped content of type multipart/alternative-------------- next part -------------- A non-text attachment was scrubbed... Name: ICFEM1pg.pdf Type: application/pdf Size: 105338 bytes Desc: not available Url : http://compgeom.poly.edu/pipermail/compgeom-announce/attachments/20030228/bfb67b60/ICFEM1pg.pdf