I need to perform element by element subtractions within a matrix.
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I have a 21x2 matrix for a given row say row 12, I need to calculate the errors by using the following numerical schemes; backwards - ((y(12)-y(11)/x(12)-x(11)), forwards - (y(13)-y(12))/(x(13)-x(12), and central (y(13)-y(11))/(x(12)-x(11)). My program needs to use matrix based calculations to solve for each element of the matrix. The following code works for the forward but I cant get the backwards or central working.
yn1 =y(2:length(y));
yn = y(1:length(y)-1);
xn1 =x(2:length(x));
xn = x(1:length(x)-1);
Thanks for the help
Answers (1)
Image Analyst
on 27 Sep 2022
Edited: Image Analyst
on 27 Sep 2022
5 Comments
Steven Lord
on 28 Sep 2022
Edited: Steven Lord
on 28 Sep 2022
It's one of the building blocks you need.
x = (1:5).^2
y = diff(x)
check = [y(3), x(4)-x(3)] % should match
Read carefully through the diff documentation page, paying specific attention to the "Approximate Derivatives with diff" example and the description of the dim input argument.
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