An array for multiple LHS assignment cannot contain expressions

I have array of values (192x2) and I want find the minimal value index (I don't care about the value);

This syntax makes sense to me but is not permitted:

index = zeros (ratio_channels, 1);

for i = 1: ratio_channels
    [~, index (i)] = min (compare_onset(i), [], 2)
end

Error: An array for multiple LHS assignment cannot contain expressions.

Running it another way works but doesn't give me what I want (the value but not the index):

for i = 1: ratio_channels
    index (i) = min (compare_onset(i), [], 2)
end

[Fangjun Jiang]

what is the size of compare_onset(i), for example

size(compare_onset(1))

Answer 1

[Fangjun Jiang]

Remove the white space in "index (i)"

[~, index(i)] = min (compare_onset(i), [], 2)