gusucode.com > symbolic工具箱matlab源码程序 > symbolic/@sym/expint.m
function Y = expint(X,Z) %EXPINT Exponential integral function. % Y = EXPINT(N,X) is the 2-argument version of the exponential % integral. It is defined as: % % EXPINT(n,x) = integral from 1 to Inf of exp(-x*t)/t^n dt % % The function EXPINT can also be called with 1 argument. % % Y = EXPINT(X) is the exponential integral function. The % exponential integral is defined as: % % EXPINT(x) = integral from x to Inf of (exp(-t)/t) dt, % % for x > 0. By analytic continuation, EXPINT is a scalar-valued % function in the complex plane. % % See also EXPINT, SYM/EI. % Copyright 2013 The MathWorks, Inc. if nargin == 1 N = sym(1); else N = X; X = Z; end Y = privBinaryOp(N,X,'symobj::vectorizeSpecfunc','Ei','infinity'); end