5th semester files

5th-Semester-Fall-2023/EEMAGS/Homework/H04.m

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+clear;
+clf;
+
+N = 50;
+L = 20.0;
+h = L/N;
+c = 1;
+tau = h/c;
+nstep = 50;
+
+coef = c * tau / (2*h);
+
+sig=0.1;                            % width of the pulse
+z = ((1:N) - 1/2)*h - L/2;          % value of z at time 0
+phi = (sech(z / (2 * sig^2))).^2;   % wave shape
+phiset = zeros(nstep, N);
+
+x = z;
+t = 0:tau:(nstep - 1) * tau;
+[xx, tt] = meshgrid(x, t);
+
+for ist = 1:nstep
+  phiset(ist,:) = phi;
+
+  for k = 1:N
+    if ( k ~= 1 ) && ( k ~= N )
+      phinew(k) = (0.5-coef)*phi(k+1) + (0.5+coef)*phi(k-1);
+    else
+      phinew(1) = (0.5-coef)*phi(2) + (0.5+coef)*phi(N);
+      phinew(N) = (0.5-coef)*phi(1) + (0.5+coef)*phi(N-1);
+    end
+  end
+  phi = phinew;
+end
+
+surf(xx, tt, phiset);