perform interpolation each row of a matrix

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wangm
wangm on 3 Feb 2023
Commented: Fangjun Jiang on 3 Feb 2023
i have a matrix A with one million rows, and each row is monotonic increase. the value in each row is x.
The interpolation is perform to obtain one million yi for each row given a constant xi value (xi is the same for each row) and given an array y (y is also the same for each row). is there an efficient way to get yi other than using loop.
right now i have to use loop like this:
for i = 1:1e6
yi(i) = interpi(A(i,:), y, xi);
end

Answers (1)

Fangjun Jiang
Fangjun Jiang on 3 Feb 2023
Edited: Fangjun Jiang on 3 Feb 2023
You can use interp1() directly for this without for-loop.
x=1:10;
A=(1:10)'+(1:10);
xi=5;
y=interp1(x,A',xi)
y = 1×10
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  5 Comments
wangm
wangm on 3 Feb 2023
wait, you did not answer my question. in my question, matrix A is x, but you matrix A is y.
Fangjun Jiang
Fangjun Jiang on 3 Feb 2023
I was taking some guesses on your question. Now you need to clarify these. "the value in each row is x", "in my question, matrix A is x", "but you matrix A is y".
The best way is to provide a complete numerical example, including the value for x, xi, y.
You don't need to provide one million rows. Three row is sufficient.

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