STIELTJES CALCULATION OF MULTIGROUP ROSSELAND AND PLANCK PHOTON LENGTHS
G. M. Eliseev, V. G. Eliseev, N. N. Zhilnikova, P. G. Kuznetsov, A. V. Tikhonov VANT. Ser.: Mat. Mod. Fiz. Proc 2008. Вып.3. С. 68-73.
Described here is the calculation method of product quadrature of two functions using Stieltjes integration. Stieltjes integration function is represented as Riemann integral of one of the functions with variable upper limit. It is approximated by the fourth-order polynomial Hermitian interpolating spline local on the average. The application of the method to calculate multigroup photon lengths in materials with weighting Rosseland and Planck function reduces the calculation time by approximately 30%. Given here are Fortran codes to calculate the integrals of these weighting functions.
|