gusucode.com > symbolic工具箱matlab源码程序 > symbolic/@sym/psi.m
function P = psi(k,X) %PSI Symbolic Psi (polygamma) function. % psi(X) = diff(gamma(X))/gamma(X). % psi(k,X) = k-th derivative of psi(X) % Copyright 2013 The MathWorks, Inc. if nargin == 1 X = k; k = sym(0); end P = privBinaryOp(k, X, 'symobj::vectorizeSpecfunc', 'symobj::psi', 'infinity'); end