Polynominal_Interopolation_test.zip_certaincli_imagec2s_插值法研究数据的

function [error_1, error_2] = Polynominal_Interopolation(f, a, b, n) syms x; f(x) = f; x0 = a; h = (b-a) / n; %段间距离 for i = 1 : (n+1) X(i) = x0 + (i-1)*h; Y(i) = f(X(i)); end % 线性插值函数 for i = 1 : n P1(i) = Y(i)*(x-X(i+1))/(X(i)-X(i+1)) + Y(i+1)*(x-X(i))/(X(i+1)-X(i)); end sum_1 = 0; for i = 1 : n sum_1 = sum_1 + int((P1(i)-f(x))^2, X(i), X(i+1)); end error_1 = double(sum_1); % for i = 1 : n % ezplot(P1(i), [X(i), X(i+1)]); % hold on; % end % hold on % plot(X, Y, 'r.'); % ezplot(P1(1), [X(1), X(1+1)]); % hold on; % ezplot(P1(2), [X(2), X(2+1)]); %分段抛物插值 for i = 1 : 2 : n P2(i) = Y(i)*(x-X(i+1))*(x-X(i+2))/((X(i)-X(i+1))*(X(i)-X(i+2))) + Y(i+1)*(x-X(i))*(x-X(i+2))/((X(i+1)-X(i))*(X(i+1)-X(i+2))) + Y(i+2)*(x-X(i))*(x-X(i+1))/((X(i+2)-X(i))*(X(i+2)-X(i+1))); end sum_2 = 0; for i = 1 : 2 : n sum_2 = sum_2 + int((P2(i)-f(x))^2, X(i), X(i+2)); end error_2 = double(sum_2); % ezplot(P2(i), [X(i), X(i+1)]); % hold on; % plot(X, Y, 'r.');