Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: harmoniczne sferyczne

Sortuj według:

Ogranicz wyniki do:

Problems and methods of calculating the Legendre functions of arbitrary degree and order

Novikova E., Dmitrenko A.

Geodesy and Cartography

2016

Vol. 65, no. 2

283--312

The known standard recursion methods of computing the full normalized associated Legendre functions do not give the necessary precision due to application of IEEE754-2008 standard, that creates a problems of underflow and overflow. The analysis of the problems of the calculation of the Legendre functions shows that the problem underflow is not dangerous by itself. The main problem that generates the gross errors in its calculations is the problem named the effect of “absolute zero”. Once appeared in a forward column recursion, “absolute zero” converts to zero all values which are multiplied by it, regardless of whether a zero result of multiplication is real or not. Three methods of calculating of the Legendre functions, that removed the effect of “absolute zero” from the calculations are discussed here. These methods are also of interest because they almost have no limit for the maximum degree of Legendre functions. It is shown that the numerical accuracy of these three methods is the same. But, the CPU calculation time of the Legendre functions with Fukushima method is minimal. Therefore, the Fukushima method is the best. Its main advantage is computational speed which is an important factor in calculation of such large amount of the Legendre functions as 2 401 336 for EGM2008.

Implementation of the spherical harmonics in glare sources simulation

Kadłubowski M., Sawicki D.

Przegląd Elektrotechniczny

2015

R. 91, nr 4

163--166

The UGR index is practically used measure of a discomfort glare for the interior working environment. The basic parameters of the index formula are the angular dependences which define the visibility of light sources. In the paper the new method for light sources description has been presented. The mathematical model using spherical harmonics is discussed. Spherical harmonics allows for convenient and efficient description of the light sources positions as well as their shapes in the field of view.

Wskaźnik UGR jest praktycznie stosowaną miarą olśnienia przykrego dla stanowisk pracy we wnętrzach. Podstawowymi parametrami wpływającymi na wartość wskaźnika są zależności kątowe w jakich widoczne są źródła światła. W artykule została przedstawiona nowa metoda opisu źródeł światła z wykorzystaniem harmonicznych sferycznych. Pozwalają one na wygodny i skuteczny opis położenia źródeł światła, jak również ich kształtu w polu widzenia.