Gradient descent method

SIRC.m

@@ -207,3 +207,7 @@ title('Instrumental variable method for the SIRC modell with additive Gaussian n
 xlabel('Time(days)');
 ylabel('Number of individuals');
 legend('S', 'I', 'R', 'C');
+
+%% Gradient descent method
+% For dCdt = gamma*q*I - (Gamma-mu)*C
+theta_C = gd(X_C2, Y_C2, [gamma_lsq2*q_lsq2, Gamma_lsq2-mu_lsq2]', 0.01, 5);

gd.m

+function theta = gd(X, y, theta, alpha, num_iters)
+m = length(y);
+for iter = 1:num_iters
+     for i=1:size(X,2)
+         theta(i) = theta(i) - alpha/m * sum((X*theta - y).*X(:,i));
+     end
+ end
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