# Computing Fresnel integrals via modified trapezium rules

• Published 2014 in Numerische Mathematik

#### Abstract

In this paper we propose methods for computing Fresnel integrals based on truncated trapezium rule approximations to integrals on the real line, these trapezium rules modified to take into account poles of the integrand near the real axis. Our starting point is a method for computation of the error function of complex argument due to Matta and Reichel (J. Math. Phys. 34 (1956), 298–307) and Hunter and Regan (Math. Comp. 26 (1972), 539–541). We construct approximations which we prove are exponentially convergent as a function of N , the number of quadrature points, obtaining explicit error bounds which show that accuracies of 10−15 uniformly on the real line are achieved with N = 12, this confirmed by computations. The approximations we obtain are attractive, additionally, in that they maintain small relative errors for small and large argument, are analytic on the real axis (echoing the analyticity of the Fresnel integrals), and are straightforward to implement. Mathematics Subject Classification (2000) 65D30 · 33B32

DOI: 10.1007/s00211-014-0627-z

### Cite this paper

@article{Alazah2014ComputingFI, title={Computing Fresnel integrals via modified trapezium rules}, author={Mohammad Alazah and Simon N. Chandler-Wilde and Scott La Porte}, journal={Numerische Mathematik}, year={2014}, volume={128}, pages={635-661} }