Possible to "expand" function handle?

Question

dm 2012-2-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/29513-possible-to-expand-function-handle

I've written a function that returns a function handle to a Lagrange polynomial L(x):

function L = lagrange(xv,yv)
% make sure xv and yv are row vectors
xv = xv(:);
yv = yv(:);
% check for equal dimensions
if size(xv) ~= size(yv)
    error('xv and yv must be of same dimensions');
end
% number of points
n = length(xv);
% initialize to zero
L = @(x)0;
for k = 1:n
    l = @(x)1; % initialize k'th basis polynomial
    for m = 1:n
        if k ~= m % if k different from m, calculate basis
            l = @(x)(l(x).*(x-xv(m))/(xv(k)-xv(m)));
        end
    end
    L = @(x)(L(x)+yv(k).*l(x)); % perform linear combination
end

It seems to work as I want it to (calling L(4), or whatever, produces the correct result), but if I type L in the command line, Matlab prints "L = @(x)(L(x)+yv(k).*l(x))".

Is it possible to get the complete function printed out? I.e., if my yv vector stems from the function x^3, then the Lagrange polynomial should be 6x^2-11x+6, but I can't figure out how to get this printed out; is it posible?

best regards

dm