拉格朗日插值matlab代码

以下是拉格朗日插值的Matlab代码实现：

function [y_interp] = lagrange_interp(x,,x_interp)
% input:
% x: vector of x values
% y: vector of y values corresponding to x
% x_interp: vector of x values to be interpolated at
% output:
% y_interp: vector of interpolated y values at x_interp

n = length(x); % number of data points

y_interp = zeros(size(x_interp)); % initialize y_interp

for i=1:n
    % calculate the Lagrange basis polynomial for this data point
    L = ones(size(x_interp));
    for j=1:n
        if j~=i
            L = L.*(x_interp-x(j))/(x(i)-x(j));
        end
    end
    
    % add the contribution of this data point to y_interp
    y_interp = y_interp + y(i)*L;
end

end