# VOIGTL — a fast subroutine for Voigt function evaluation on vector processors

## Description

Abstract Voigt function evaluations account for a significant proportion of computer time used in calculating synthetic stellar spectra, particularly if local thermodynamic equilibrium is assumed. A vectorised Voigt function evaluation routine is presented which, in typical applications, achieves a speed of 180 Mflops on a CRAY-XMP and is accurate to 13 decimal digits. A derived formula gives an order of magnitude estimate of the Voigt function absolute accuracy required for synthetic spectrum calcula... Title of program: VOIGTL Catalogue Id: ACLT_v1_0 Nature of problem Stellar line absorption coefficients are, in most cases, Voigt profiles which are convolutions of Doppler and Lorentz profiles. Voigt function evaluation is required repeatedly in synthetic stellar spectrum calculations and, in the case of local thermodynamic equilibrium being assumed, is dominant in determining computer time required. Versions of this program held in the CPC repository in Mendeley Data ACLT_v1_0; VOIGTL; 10.1016/0010-4655(93)90171-8 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)