In this report we present some of the tests we carried out to ver- ify the accuracy, reliability, and performance of a recent update to recent NAG versions of a numerical code, KYPRIX, specifically written for the solution of the Kompaneets equation in cosmological context, first implemented in the years 1989-1991, aimed to the very accurate computation of the cosmic microwave back- ground (CMB) spectral distortions under quite general assumptions. After a brief introduction on general aspects concerning the global computational time and the impact of the various aspects of the code on it and on the accuracy of the numeri- cal integration, we focus on some dedicated tests. First we compare the results of the update version of the code with those obtained with the original one, for some representative cases. Then we discuss to specific quantitative tests: the energy conservation and the time behaviour of the electron temperature. Finally we fo- cus on some properties of the free-free distortions relevant for the long wavelength region of the CMB spectrum. All the tests support the very good accuracy and reliability of the new code version.
Accuracy and performance of a numerical code for the solution of the Kompaneets equation in cosmological context
PROCOPIO, Pietro;BURIGANA, Carlo
2005
Abstract
In this report we present some of the tests we carried out to ver- ify the accuracy, reliability, and performance of a recent update to recent NAG versions of a numerical code, KYPRIX, specifically written for the solution of the Kompaneets equation in cosmological context, first implemented in the years 1989-1991, aimed to the very accurate computation of the cosmic microwave back- ground (CMB) spectral distortions under quite general assumptions. After a brief introduction on general aspects concerning the global computational time and the impact of the various aspects of the code on it and on the accuracy of the numeri- cal integration, we focus on some dedicated tests. First we compare the results of the update version of the code with those obtained with the original one, for some representative cases. Then we discuss to specific quantitative tests: the energy conservation and the time behaviour of the electron temperature. Finally we fo- cus on some properties of the free-free distortions relevant for the long wavelength region of the CMB spectrum. All the tests support the very good accuracy and reliability of the new code version.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
