Guassian Function, for loop only runs once???
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a=[A,B];
for i=1:4;
a(2,i)=a(2,i)-(a(2,1)/a(1,1)).*a(1,i)
end
This is one of my first lines in my function but I do not know what this for loop only runs once A is a 3X3 matrix and B is a 3X1 which I combined for an augmented matrix
2 个评论
Adam Danz
2019-2-4
The four-loop definitely runs 4 times.
As evidence, insert this line anywhere inside your for-loop and the iteration number will be displayed in the command window.
fprintf('iteration #%d\n', i)
Only the 2nd row of 'a' will be affected by your code. Perhaps that's causing unexpected results?
Abigail Osborne
2019-2-4
采纳的回答
You're probably indexing incorrectly and instead of using the variable 'i', you're accidentally using a hard-coded value (maybe 1, by accident?)
Here's why your values aren't changing.
On the first iteration, you are replacing the value a(2,1) with a zero (see below)
i = 1
a(2,i) = a(2,i)-(a(2,1)/a(1,1)).*a(1,i)
% |______________________| this section is merely (Q/R) * R which just equals Q on the first iteration
% that reduces to
a(2,i) = a(2,i) - a(2,i) % which equals 0
On all following iterations, you're using that zero in the numerator of a fraction which will always equal 0 (see below)
i = 1 %, 3, 4
a(2,i) = a(2,i)-(a(2,1)/a(1,1)).*a(1,i)
% ( 0 /a(1,1)).*a(1,i) and that will always equal 0
% so = a(2,i) - 0 that will never change the value of a(2,i)
All of this results in only 1 change and that change happens on the first iteration in position a(2,1).
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