PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 7

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  przedział obliczeń
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Implementacja arytmetyki przedziałowej z wykorzystaniem rozszerzeń multimedialnych SSE oraz zmodyfikowanej metody dzielenia przedziałowego
Pilarek M.
Metody Informatyki Stosowanej
|
2010
|
nr 2 (23)
127-135
PL
Otrzymane wyniki badań potwierdzają, że zastosowanie rozszerzeń multimedialnych SSE w zagadnieniach związanych z arytmetyka˛ przedziałową znacznie skraca czas wykonywania obliczeń. Biblioteki Profil/BIAS oraz Boost, które zostały zaimplementowane z pominięciem rozszerzeń multimedialnych wykonują. obliczenia zdecydowanie dłużej. Zastosowanie innego formatu przechowywania przedziałów w pamięci ([a --- a]) oraz odpowiednie zmodyfikowanie operacji arytmetycznych pozwoliło na wykonywanie obliczeń bez ciągłej zmiany trybu zaokrąglania, co nie spowodowało utraty wydajności. Ponadto zastosowana w naszej implementacji zmodyfikowana metoda dzielenia bazująca na koncepcji metody "rozszerzonego przedziałowego zero" pozwala na uzyskiwanie znacznie węższych przedziałów, bez utraty wydajności.
EN
The aim of this paper is to show interval arithmetics implementation using single-instructionmultiple- data (SIMD) SSE (Streaming SIMD Extensions) multimedia instructions, and register set extensions. It was proven previously that SSE extensions can increase performance of interval calculations, since both interval bounds can be kept in one SSE register and all arithmetic operations can be done in parallel. In this work a new approach to the modified interval division is proposed based on the concept of “interval extended zero” method which is a part of this implementation. This method allows us to reduce the undesirable excess width effect. We show the results obtained for several randomly generated matrices using different algorithms (matrix-matrix multiplication, Gauss elimination) and compare them also with results obtained using other interval libraries.
2
Shared-Memory Parallelization of an Interval Equations Systems Solver - Comparison of Tools
Kubica B.J.
Prace Naukowe Politechniki Warszawskiej. Elektronika
|
2009
|
z. 169
121-128
EN
This paper considers the shared-memory parallelization of an interval solver of underdetermined systems of nonlinear equations. Four threading libraries are investigated: OpenMP, POSIX threads, Boost threads and TBB. Directions for further investigations on multi-threaded interval algorithms are outlined.
3
Performance inversion of interval Newton narrowing operators
Kubica B.J.
Prace Naukowe Politechniki Warszawskiej. Elektronika
|
2009
|
z. 169
111-119
EN
This paper describes a phenomenon of performance inversion of Newton operators - more precise operators might result in longer computation of a branch-and-prune method. Examples are presented and possible reasons of this behavior are discussed.
4
Breakthrough in Interval Data Fitting II. From Ranges to Means and Standard Deviations
Gutowski M.W.
Prace Naukowe Politechniki Warszawskiej. Elektronika
|
2009
|
z. 169
73-78
EN
Interval analysis, when applied to the so called problem of experimental data fitting, appears to be still in its infancy. Sometimes, partly because of the unrivaled reliability of interval methods, we do not obtain any results at all. Worse yet, if this happens, then we are left in the state of complete ignorance concerning the unknown parameters of interest. This is in sharp contrast with widespread statistical methods of data analysis. In this paper I show the connections between those two approaches: how to process experimental data rigorously, using interval methods, and present the final results either as intervals (guaranteed, rigorous results) or in a more familiar probabilistic form: as a mean value and its standard deviation.
5
Breakthrough in Interval Data Fitting I. The Role of Hausdorff Distance
Gutowski M.W.
Prace Naukowe Politechniki Warszawskiej. Elektronika
|
2009
|
z. 169
63-72
EN
This is the first of two papers describing the process of fitting experimental data under interval uncertainty. Probably the most often encountered application of global optimization methods is finding the so called best fitted values of various parameters, as well as their uncertainties, based on experimental data. Here I present the methodology, designed from the very beginning as an interval-oriented tool, meant to replace to the large extent the famous Least Squares (LSQ) and other slightly less popular methods. Contrary to its classical counterparts, the presented method does not require any poorly justified prior assumptions, like smallness of experimental uncertainties or their normal (Gaussian) distribution. Using interval approach, we are able to fit rigorously and reliably not only the simple functional dependencies, with no extra effort when both variables are uncertain, but also the cases when the constitutive equation exists in implicit rather than explicit functional form. The magic word and a key to success of interval approach appears the Hausdorff distance.
6
Exploring the search space with intervals
Gutowski M.
Prace Naukowe Politechniki Warszawskiej. Elektronika
|
2008
|
z. 165
77-84
EN
The term global optimization is used in several contexts. Most often we are interested in finding such a point (or points) in many-dimensional search space at which the objective function's value is optimal, i.e. maximal or minimal. Sometimes, however, we are also interested in stability of the solution, that is in its robustness against small perturbations. Here I present the original, interval-analysis-based family of methods designed for exhaustive exploration of the search space. The power of interval methods makes it possible to reach all mentioned goals within a single, unified framework.
7
Can interval computations be applied over spaces of non-numbers?
Kubica B.
Prace Naukowe Politechniki Warszawskiej. Elektronika
|
2008
|
z. 165
103-112
EN
Interval methods proved to be a useful tool for solving global optimization and nonlinear equations systems problems over Rn. But an interval may be defined not only over the set of real numbers or real vectors, but over any partially ordered set. The paper shows how basic ideas of interval computations can be generalized for such spaces. Some specific applications are proposed and preliminary computational results are presented.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.