# IJPAM: Volume 36, No. 2 (2007)

NUMERICAL CONFORMAL MAPPING OF
DOUBLY CONNECTED REGIONS VIA
THE KERZMAN-STEIN KERNEL

Ali H.M. Murid, Nurul Akmal Mohamed
Department of Mathematics
Faculty of Science
University of Technology of Malaysia
81310, UTM Skudai, Johor Darul Ta'zim, MALAYSIA
e-mail: ahmm@mel.fs.utm.my
e-mail: akmalmohdy@yahoo.com.my

Abstract.An integral equation method based on the Kerzman-Stein kernel for conformal mapping of smooth doubly connected regions onto an annulus is presented. The theoretical development is based on the boundary integral equation for conformal mapping of doubly connected regions with Kerzman-Stein kernel derived by Razali and one of the authors [#!murid2!#]. However, the integral equation is not in the form of Fredholm integral equation and no numerical experiments are reported. In this paper, we show that using the boundary relationship satisfied by a function analytic in a doubly connected region, then the previous integral equation can be reduced to a numerically tractable integral equation which however involves the unknown inner radius, . For numerical experiments, we discretized the integral equation which leads to an over determined system of non-linear equations. The system obtained is solved simultaneously using Gauss-Newton method and Lavenberg-Marquardt with Fletcher's algorithm for solving the non-linear least squares problems. Numerical implementations on some test regions are also presented.