function fig314 clf tmax=250; % get(gcf) set(gcf,'Position', [831 626 499 158]); % numerical solution ep=0.01 % x-axis g(x) u (t=5) u (t=10) load fisher1.txt x1=fisher1(:,1); u1=fisher1(:,2); u1x=fisher1(:,3); u1y=fisher1(:,4); ep=0.01; nx=200; lambda=1; x=linspace(-10,20,nx); t1=5; t2=10; for ix=1:nx arg1 = t1 - lambda*x(ix) + lambda^2*ep*t1; arg2 = t2 - lambda*x(ix) + lambda^2*ep*t2; a1(ix) = 1/(1+exp(-arg1)); a2(ix) = 1/(1+exp(-arg2)); end; hold on box on grid on say=['\epsilon = 0.01']; text(-8,0.2,say,'FontSize',14,'FontWeight','bold') plot(x1,u1,'-r','Linewidth',1) plot(x1,u1x,'-r','Linewidth',1) plot(x1,u1y,'-r','Linewidth',1) plot(x,a1,'--','Linewidth',1) plot(x,a2,'--','Linewidth',1) text(-4.5,0.84,'t = 0','FontSize',14,'FontWeight','bold') text(1.7,0.64,'t = 5','FontSize',14,'FontWeight','bold') text(6.9,0.44,'t = 10','FontSize',14,'FontWeight','bold') loc='SouthEast'; xlabel('x-axis','FontSize',14,'FontWeight','bold') ylabel('Solution','FontSize',14,'FontWeight','bold') set(gca,'FontSize',14); %legend(' Exact Solution',' y_0(t)+\epsilon y_1(t)','Location',loc); set(findobj(gcf,'tag','legend'),'FontSize',14); hold off figure % numerical solution ep=0.1 % x-axis g(x) u (t=5) u (t=10) load fisher2.txt x2=fisher2(:,1); u2=fisher2(:,2); u2x=fisher2(:,3); u2y=fisher2(:,4); ep=0.1; for ix=1:nx arg1 = t1 - lambda*x(ix) + lambda^2*ep*t1; arg2 = t2 - lambda*x(ix) + lambda^2*ep*t2; a1(ix) = 1/(1+exp(-arg1)); a2(ix) = 1/(1+exp(-arg2)); end; % get(gcf) set(gcf,'Position', [312 504 499 158]); hold on box on grid on say=['\epsilon = 0.1']; text(-8,0.2,say,'FontSize',14,'FontWeight','bold') plot(x2,u2,'-r','Linewidth',1) plot(x2,u2x,'-r','Linewidth',1) plot(x2,u2y,'-r','Linewidth',1) plot(x,a1,'--','Linewidth',1) plot(x,a2,'--','Linewidth',1) text(-4.5,0.84,'t = 0','FontSize',14,'FontWeight','bold') text(1.7,0.64,'t = 5','FontSize',14,'FontWeight','bold') text(6.9,0.44,'t = 10','FontSize',14,'FontWeight','bold') %axis([0 tmax -0.601 0.6]) %loc='NorthWest'; loc='SouthEast'; xlabel('x-axis','FontSize',14,'FontWeight','bold') ylabel('Solution','FontSize',14,'FontWeight','bold') set(gca,'FontSize',14); %legend(' Exact Solution',' y_0(t)+\epsilon y_1(t)','Location',loc); set(findobj(gcf,'tag','legend'),'FontSize',14);