Positivity Preserving using GC^1 Rational Quartic Spline

In this paper, we study the shape preserving interpolation for positive data using a rational quartic spline which has a quartic numerator and linear denominator. The rational quartic splines have continuity at join knots. Simple data dependent constraints are derived on the shape parameters in the description of the rational interpolant. Numerical comparison between the proposed scheme and the existing scheme will be discussed. The results indicate that the proposed scheme works well for all tested data sets.