How to find the min values and their indices for a 2D array?

I have the following 10x5 array: LLP

I want to get the min value of this array and all its induces. I mean (4,5), (5,1), (5,2)....and so on

Answer 1

[Adam Danz]

Find the minimum value using min and specify all dimensions. Then use find with two outputs to find the row and column indices of the matrix that equal the minimum value.

% demo data
m = [3 0 1 0 2; 2 2 0 0 3]

m = 2×5

3 0 1 0 2 2 2 0 0 3

minval = min(m,[],'all');
[row, col] = find(m == minval)

row = 4×1

1 2 1 2

col = 4×1

2 3 4 4

Common pitfalls

min() has a second output that returns the indicies of the min value but, by default, it will return the row index of the first matching minimum value for each column.

[minval, idx] = min(m)

minval = 1×5

2 0 0 0 2

idx = 1×5

2 1 2 1 1

You can specify the linear option to return the linear index rather than a row index but this will still return the first matching minimum for each column, not all matches of the global minimum.

[minval, idx] = min(m,[],'linear')

minval = 1×5

2 0 0 0 2

idx = 1×5

2 3 6 7 9

If you specify all dimensions, it will return the first match of the minimum value, with or without the linear option.

[minval, idx] = min(m,[],'all')

minval = 0

idx = 3

[ilyes louahem m'sabah]

I made a copy paste of your solution and i got this error

Error using min

Trailing string input must be 'omitnan' or 'includenan'.

[Matt J]

For older Matlab versions prior to MATLAB R2018b, do instead,

minval = min(m(:));

[ilyes louahem m'sabah]

Yes, it works now. Thank you Matt J

[ilyes louahem m'sabah]

now i have another matrix called f with the same dimension of m. I want to find the min of the values of f corresponding to the indices found in m. I mean the indices row and col .

I want something like this: min(f(row,col))

[Adam Danz]

Convert the (row, col) subscript indices to a linear index using sub2ind. Demo:

m = [3 0 1 0 2; 2 2 0 0 3]

m = 2×5

3 0 1 0 2 2 2 0 0 3

minval = min(m,[],'all');
[row, col] = find(m == minval)

row = 4×1

1 2 1 2

col = 4×1

2 3 4 4

f = rand(size(m))

f = 2×5

0.0784 0.5513 0.4124 0.9789 0.3237 0.6348 0.8458 0.7896 0.7465 0.1948

ind = sub2ind(size(m),row,col);
f(ind)

ans = 4×1

0.5513 0.7896 0.9789 0.7465