e941.m

matlab算法集 matlab算法集

%-------------------------------------------------------------------
% Example 9.4.1: Heat Flow in a Plate 
%-------------------------------------------------------------------

% Initialize 

   clc
   clear
   a = 4;             % maximum x
   b = 4;             % maximum y
   m = 20;            % t precision 		
   n = 19;            % x precision 
   p = 19;            % y precision 
   T = 1.e4;	      % final time 
   beta = 1.0e-4;     % thermal diffusivity 

% Boundary value function

   g = inline ('exp(y)*cos(x) - exp(x)*cos(y)','t','x','y');

% Compute gammas

   fprintf ('Example 9.4.1: Heat Flow in a Plate\n');
   T = prompt ('Enter final time',0,T,T/2);
   dt = T/m;
   dx = a/(n+1);
   dy = b/(p+1);
   gx = beta*dt/(dx*dx);
   gy = beta*dt/(dy*dy);
   show ('gamma_x',gx);
   show ('gamma_y',gy);

% Solve heat equation

   disp ('Solving heat equation ...')
   [x,y,U] = heat2 (T,a,b,m,n,p,beta,'',g);
   caption = sprintf ('Plate Temperature: t = %g',T);
   plotxyz (x,y,U,caption,'x','y','u')
%-------------------------------------------------------------------