weak_prob1.m

来自「drlt 边界限元程序」· M 代码 · 共 39 行

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                   %
% Singular (ln(x)) Gauss integration for 3 Gauss points             %
%                                                                   %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

clear

% Integration domain
a=0;
b=1;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% n = 3

% weights
w3s=[0.51340455 0.39198004 0.09461541];


% Gauss points on [0,1]
st3s=[0.06389079 0.36899706 0.76688030];


integ3s = w3s * f_prob1(st3s)'

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%Plot function

x=(a:0.01:b);
y=f_prob1(x);
figure(1)
plot(x,-y.*log(x),'Linewidth',2)
xlabel('x','FontSize',16)
ylabel('f(x)','FontSize',16)
title([' Problem 1: f(x)'],'Fontsize',16)
grid on;