Evaluation of the exponential integral for large complex arguments
Evaluation of the exponential integral for large complex arguments
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大型复数参数的指数积分计算
DOI：
10.6028/jres.052.045
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发表时间：
1954
影响因子：
--
通讯作者：
J. Todd
中科院分区：
文献类型：
--
作者：
J. Todd
已由国家标准局编制[1]；该表的导言给出了这一功能的准确定义。此表涵盖了IXL~20、IYL~20的范围，参数的间距各不相同。为了计算E_1(Z)在这个范围内(或在这个范围内，插值不方便的点，具有较大自变量的点)，可以考虑几种方法。我们对这两种方法进行了详细的分析，并推荐了拉盖尔求积，这在孤立论元的情况下当然是可行的。
has been prepared by th e National Bureau of Standards [1]; 1 th e introduction to the table gives a precise definition of this function. This table covers the range Ixl ~ 20, Iyl ~ 20, with argumcnts variously spaced. In order to compute E1( z) olltsid e this range, (or within this range, a t points where interpolation is awkward, which are those with comparatively large argument), several methods can be considered. We examine t wo in detail and recommend th e Laguerre quadrature, which is certainly practicable in th e case of isolated arguments.