x2lnx.m

来自「nonlinear eq routines in matlab」· M 代码 · 共 22 行

function varargout = x2lnx(x)
%
% 
%
%  [y]    = x2lnx(x)    returns the function value y = (x^2-1)^p ln(x)
%  [y,yp] = x2lnx(x)  returns the function value in y and 
%                       the derivative in yp
%
%  Matthias Heinkenschloss
%  Department of Computational and Applied Mathematics
%  Rice University
%  March 29, 2001
%


global p
% return the function value
varargout{1} = (x.^2-1).^p .* log(x);
if( nargout > 1 )
  % return the derivative as the second argument
  varargout{2} = 2*p*x.*(x.^2-1).^(p-1) .* log(x) + (x.^2-1).^p ./ x;
end