Matrix - Vector value matching

Question

Brandon Bush 2019-8-1

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/474459-matrix-vector-value-matching

编辑： the cyclist 2019-8-1

Matrix = magic(20);
Leroy = randi(20,20,1);
for i = 1:length(Leroy)
    [Jenkins, J] = min(min(Leroy(i) - Matrix);
end

In my current project, I need to find values inside of an matrix that match with individual vector values. This is an example of the process; the main program has me using lat and lon values. But I create a 20x20 matrix and then a 20x1 array of randomly placed values.

When i do the for loop, each iteration of the Leroy vector is subtracted from every value in matrix. The first min function should return the smallest value from each column and its correspoding index. The second min function should return the smallest overall value from the first min function. and which index had the smallest value.

My concern is that im not sure which integer inside the matrix returned the smallest value. Is there a way I can use the indexes or something to figure that out?

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Answer 1

the cyclist 2019-8-1

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https://ww2.mathworks.cn/matlabcentral/answers/474459-matrix-vector-value-matching#answer_385793

编辑：the cyclist 2019-8-1

在 MATLAB Online 中打开

In each iteration of the for loop, you are looking for the closest value (regardless of whether it is larger or smaller)? One way to do that would

Jenkins = zeros(20,1);
J       = zeros(20,1);
for i = 1:length(Leroy)
    [Jenkins(i), J(i)] = min(abs(Leroy(i) - Matrix(:)));
end

Then Jenkins will be the minimum difference (in absolute terms), and J will be the linear index to the Matrix location. You can get the subscripted indices (i.e. row & column index) using

[m,n] = ind2sub([20,20],J);

You can read more about linear indexing in the documentation here.