# My function doesn't append to it's list

조회 수: 6 (최근 30일)
Kacper 2024년 5월 10일
댓글: Kacper 2024년 5월 12일
%calculates polynomials of form Pk = ((2k-1)t/k)*Pk-1 - ((k-1)/k)*Pk-2
function [poly, filllist] = calc_poly (n, t, filllist)
if n == 0
filllist = [filllist; ones(size(t))];
poly = ones(size(t));
return
end
if n == 1
filllist = [filllist; t];
poly = t;
return
end
poly = ((2*n-1)/n)*t.*calc_poly(n-1, t, filllist) - ((n-1)/n)*calc_poly(n-2, t, filllist);
filllist = [filllist; poly];
end
This function is supposed to recursively calculate the polys and append them into filllist, but the array remians unalatered after running it. I know that as it stands there would be duplicates in the list, but I first want to get the function to actually do anything.

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### 답변 (1개)

Steven Lord 2024년 5월 10일
Your recursive calls only call your function with one output argument, so the modified second output argument is not returned from that function. Therefore any changes you make to your third input argument are discarded when each recursive call returns.
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Walter Roberson 2024년 5월 12일
Experiment with creating a script that has both parts together, and running the script. You can use the "Copy" box on the code I posted to get the code to be pasted into the script.
Kacper 2024년 5월 12일
I pasted your code to a new script and it worked, despite the previous script being the same. huh. Anyway, thx for your answers!

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