function f = p14_fun ( n, p ) %*****************************************************************************80 % %% P14_FUN evaluates the integrand for problem 14. % % Integrand: % % f(x,y) = 1 / sqrt ( X ) + 1 / sqrt ( Y ) + 1 / sqrt ( X + Y ) % % Vertices: % % (0,0), (1,0), (0,1) % % Integral: % % 10/3 % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 10 April 2007 % % Author: % % John Burkardt % % Reference: % % Elise deDoncker, Ian Robinson, % Algorithm 612: % Integration over a Triangle Using Nonlinear Extrapolation, % ACM Transactions on Mathematical Software, % Volume 10, Number 1, March 1984, pages 17-22. % % Parameters: % % Input, integer N, the number of evaluation points. % % Input, real P(2,N), the evaluation points. % % Output, real F(N), the function values. % f(1:n) = 3.0 / 10.0 * ( ... 1.0 ./ sqrt ( p(1,1:n) ) ... + 1.0 ./ sqrt ( p(2,1:n) ) ... + 1.0 ./ sqrt ( p(1,1:n) + p(2,1:n) ) ); return end