eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
18
10.4230/DagSemProc.06021.1
article
06021 Abstracts Collection – Reliable Implementation of Real Number Algorithms: Theory and Practice
Hertling, Peter
Hoffmann, Christoph M.
Luther, Wolfram
Revol, Nathalie
From 08.01.06 to 13.01.06, the Dagstuhl Seminar 06021 ``Reliable Implementation of Real Number Algorithms: Theory and Practice'' was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper.
The first section describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.1/DagSemProc.06021.1.pdf
Real number algorithms
reliable implementation
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
5
10.4230/DagSemProc.06021.2
article
06021 Summary – Reliable Implementation of Real Number Algorithms: Theory and Practice
Hertling, Peter
Hoffmann, Christoph M.
Luther, Wolfram
Revol, Nathalie
The seminar brought together researchers from many different disciplines concerned with the reliable implementation of real number algorithms either from a theoretical or from a practical point of view. In this summary we describe the topics, the goals, and the contributions of the seminar.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.2/DagSemProc.06021.2.pdf
Real number computability
real number algorithms
reliable computing
algorithms with result verification
interval arithmetic
geometric computing
robustness
solid modeling
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
12
10.4230/DagSemProc.06021.3
article
A Descartes Algorithms for Polynomials with Bit-Stream Coefficients
Mehlhorn, Kurt
Eigenwillig, Arno
Kettner, Lutz
Krandick, Werner
Schmitt, Susanne
Wolpert, Nicola
The Descartes method is an algorithm for isolating the
real roots of square-free polynomials with real coefficients. We assume
that coefficients are given as (potentially infinite) bit-streams. In other
words, coefficients can be approximated to any desired accuracy, but are not
known exactly. We show that
a variant of the Descartes algorithm can cope with bit-stream
coefficients. To isolate the real roots of a
square-free real polynomial $q(x) = q_nx^n+ldots+q_0$ with root
separation $
ho$, coefficients $abs{q_n}ge1$ and $abs{q_i} le 2^ au$,
it needs coefficient approximations to $O(n(log(1/
ho) + au))$
bits after the binary point and has an expected cost of
$O(n^4 (log(1/
ho) + au)^2)$ bit operations.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.3/DagSemProc.06021.3.pdf
Root Isolation
Interval Arithmetic
Descartes Algorithm
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
25
10.4230/DagSemProc.06021.4
article
A Proposal to add Interval Arithmetic to the C++ Standard Library
Pion, Sylvain
Brönnimann, Hervé
Melquiond, Guillaume
I will report on a recent effort by Guillaume Melquiond, HervÃƒÂ© Br"onnimann
and myself to push forward a proposal to include interval arithmetic in the
next C++ ISO standard. The goals of the standardization are to produce a
unified specification which will serve as many uses of intervals as possible,
together with hoping for very efficient implementations, closer to the
compilers. I will describe how the standardization process works, explain
some of the design choices made, and list some of the other questions arising
in the process. We welcome any comment on the proposal.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.4/DagSemProc.06021.4.pdf
Interval arithmetic
C++
ISO standard
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
11
10.4230/DagSemProc.06021.5
article
Floating Point Geometric Algorithms for Topologically Correct Scientific Visualization
Peters, Thomas J.
Moore, Edward L. F.
The unresolved subtleties of floating point computations in geometric modeling become considerably more difficult in animations and scientific visualizations.
Some emerging solutions based upon topological considerations will be presented.
A novel geometric seeding algorithm for Newton's method was used in experiments to determine feasible support for these visualization applications.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.5/DagSemProc.06021.5.pdf
Geometry
algorithm
visualization
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
12
10.4230/DagSemProc.06021.6
article
Interval Arithmetic Using SSE-2
Lambov, Branimir
We present an implementation of double precision interval arithmetic using the single-instruction-multiple-data SSE-2 instruction and register set extensions. The implementation is part of a package for exact real arithmetic, which defines the interval arithmetic variation that must be used: incorrect operations such as division by zero cause exceptions, loose evaluation of the operations is in effect, and performance is more important than tightness of the produced bounds. The SSE2 extensions are suitable for the job, because they can be used to operate on a pair of double precision numbers and include separate rounding mode control and detection of the exceptional conditions. The paper describes the ideas we use to fit interval arithmetic to this set of instructions, shows a performance comparison with other freely available interval arithmetic packages, and discusses possible very simple hardware extensions that can significantly increase the performance of interval arithmetic.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.6/DagSemProc.06021.6.pdf
Interval Arithmetic
SSE2
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
0
10.4230/DagSemProc.06021.7
article
Interval Subroutine Library Mission
Corliss, George F.
Kearfott, R. Baker
Nedialkov, Ned
Pryce, John D.
Smith, Spencer
We propose the collection, standardization, and distribution of a full-featured production quality library for reliable scientific computing with routines using interval techniques for use by the wide community of applications developers.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.7/DagSemProc.06021.7.pdf
Subroutine library
problem-solving library
C++ interval standard
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
23
10.4230/DagSemProc.06021.8
article
Robustness and Randomness
Michelucci, Dominique
Moreau, Jean Michel
Foufou, Sebti
Robustness problems of computational geometry algorithms is a topic that has been subject to intensive research efforts from both computer science and mathematics communities. Robustness problems are caused by the lack of precision in computations involving floating-point instead of real numbers. This paper reviews methods dealing with robustness and inaccuracy problems. It discussed approaches based on exact arithmetic, interval arithmetic and probabilistic methods. The paper investigates the possibility to use randomness at certain levels of reasoning to make geometric constructions more robust.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.8/DagSemProc.06021.8.pdf
Robustness
interval
randomness
inaccuracy
geometric computation
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
12
10.4230/DagSemProc.06021.9
article
Transfinite interpolation for well-definition in error analysis in solid modelling
Stewart, Neil
Zidani, Malika
An overall approach to the problem of error analysis in the context of solid modelling, analogous to the standard forward/backward error analysis of Numerical Analysis, was described in a recent paper by Hoffmann and Stewart. An important subproblem within this overall approach is the well-definition of the sets specified by inconsistent data. These inconsistencies may come from the use of finite-precision real-number arithmetic, from the use of low-degree curves to approximate boundaries, or from terminating an infinite convergent (subdivision) process after only a finite number of steps.
An earlier paper, by Andersson and the present authors, showed how to resolve this problem of well-definition, in the context of standard trimmed-NURBS representations, by using the Whitney Extension Theorem. In this paper we will show how an analogous approach can be used in the context of trimmed surfaces based on combined-subdivision representations, such as those proposed by Litke, Levin and SchrÃƒÂ¶der.
A further component of the problem of well-definition is ensuring that adjacent patches in a representation do not have extraneous intersections. (Here, "extraneous intersections" refers to intersections, between two patches forming part of the boundary, other than prescribed intersections along a common edge or at a common vertex.) The paper also describes the derivation of a bound for normal vectors that can be used for this purpose. This bound is relevant both in the case of trimmed-NURBS representations, and in the case of combined subdivision with trimming.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.9/DagSemProc.06021.9.pdf
Forward/backward error analysis
robustness
well-definition
trimmed NURBS
combined subdivision
trimming
bounds on normals
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
18
10.4230/DagSemProc.06021.10
article
Upper and Lower Bounds on Sizes of Finite Bisimulations of Pfaffian Dynamical Systems
Korovina, Margarita
Vorobjov, Nicolai
In this paper we study a class of dynamical systems defined by Pfaffian maps. It is a sub-class of o-minimal dynamical systems which capture rich
continuous dynamics and yet can be studied using finite bisimulations.
The existence of finite bisimulations for o-minimal dynamical and hybrid systems has been shown by several authors; see e.g. Brihaye et al (2004), Davoren (1999), Lafferriere et al (2000).
The next natural question to investigate is how the sizes of such bisimulations can be bounded. The first step in this direction was done by Korovina et al (2004) where a double exponential upper bound was shown for Pfaffian dynamical and hybrid systems. In the present paper we improve this bound to a single exponential upper bound. Moreover we show that this bound is tight in general, by exhibiting a parameterized class of systems on which the exponential bound is attained.
The bounds provide a basis for designing efficient algorithms for computing
bisimulations, solving reachability and motion planning problems.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.10/DagSemProc.06021.10.pdf
Hybrid systems
Pfaffian functions
bisimulation
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-09-13
6021
1
10
10.4230/DagSemProc.06021.11
article
Worst Cases for the Exponential Function in the IEEE 754r decimal64 Format
Lefèvre, Vincent
Stehlé, Damien
Zimmermann, Paul
We searched for the worst cases for correct rounding of the exponential
function in the IEEE 754r decimal64 format, and computed all the bad cases
whose distance from a breakpoint (for all rounding modes) is less than
$10^{-15}$,ulp, and we give the worst ones. In particular, the worst case
for $|x| geq 3 imes 10^{-11}$ is $exp(9.407822313572878 imes 10^{-2})
= 1.098645682066338,5,0000000000000000,278ldots$. This work can be
extended to other elementary functions in the decimal64 format and allows
the design of reasonably fast routines that will evaluate these functions
with correct rounding, at least in some domains.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06021/DagSemProc.06021.11/DagSemProc.06021.11.pdf
Floating-point arithmetic
decimal arithmetic
table maker's dilemma
correct rounding
elementary functions