{ "id": "1906.12023", "version": "v1", "published": "2019-06-28T02:59:40.000Z", "updated": "2019-06-28T02:59:40.000Z", "title": "Evaluation of Abramowitz functions in the right half of the complex plane", "authors": [ "Zydrunas Gimbutas", "Shidong Jiang", "Li-Shi Luo" ], "comment": "24 pages, 2 figures", "categories": [ "math.NA", "cs.NA" ], "abstract": "A numerical scheme is developed for the evaluation of Abramowitz functions $J_n$ in the right half of the complex plane. For $n=-1,\\, \\ldots,\\, 2$, the scheme utilizes series expansions for $|z|<1$ and asymptotic expansions for $|z|>R$ with $R$ determined by the required precision, and modified Laurent series expansions which are precomputed via a least squares procedure to approximate $J_n$ accurately and efficiently on each sub-region in the intermediate region $1\\le |z| \\le R$. For $n>2$, $J_n$ is evaluated via a recurrence relation. The scheme achieves nearly machine precision for $n=-1, \\ldots, 2$, with the cost about four times of evaluating a complex exponential per function evaluation.", "revisions": [ { "version": "v1", "updated": "2019-06-28T02:59:40.000Z" } ], "analyses": { "subjects": [ "33E20", "33F05", "65D15", "65E05", "65F99" ], "keywords": [ "complex plane", "right half", "abramowitz functions", "scheme utilizes series expansions", "modified laurent series expansions" ], "note": { "typesetting": "TeX", "pages": 24, "language": "en", "license": "arXiv", "status": "editable" } } }