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我有四個矢量xi1,x1,xi2和x2我打算用下面的代碼計算p。因爲我會有很多這些矢量，所以根據我需要的時間花費很多時間。 有沒有辦法做得更快？如何更快地計算一些嵌套for循環？
xi1 = rand(1,10);
x1 = [1 2 3 4 5];
n1 = length(x1) - 1;
ni1 = length(xi1);
L1 = ones(n1+1,ni1);
for k = 0 : n1 % start the outer loop through the data values for x
for kk = 0 : (k-1) % start the inner loop through the data values for x (if k = 0 this loop is not executed)
L1(kk+1,:) = L1(kk+1,:).*(xi1 - x1(k+1))/(x1(kk+1)-x1(k+1)); % see the Lagrange interpolating polynomials
end % end of the inner loop
for kk = k+1 : n1 % start the inner loop through the data values (if k = n1 this loop is not executed)
L1(kk+1,:) = L1(kk+1,:).*(xi1 - x1(k+1))/(x1(kk+1)-x1(k+1));
end % end of the inner loop
end % the end of the outer loop
p1 = prod(L1,1);
xi2 = [1 1.5];
x2 = [1 2 3 4 5];
n2 = length(x2) - 1;
ni2 = length(xi2);
L2 = ones(n2+1,ni2);
for k = 0 : n2 % start the outer loop through the data values for x
for kk = 0 : (k-1) % start the inner loop through the data values for x (if k = 0 this loop is not executed)
L2(kk+1,:) = L2(kk+1,:).*(xi2 - x2(k+1))/(x2(kk+1)-x2(k+1)); % see the Lagrange interpolating polynomials
end % end of the inner loop
for kk = k+1 : n2 % start the inner loop through the data values (if k = n2 this loop is not executed)
L2(kk+1,:) = L2(kk+1,:).*(xi2 - x2(k+1))/(x2(kk+1)-x2(k+1));
end % end of the inner loop
end % the end of the outer loop
p2 = prod(L2,1);
p = p1' * p2;