MATLAB: How to fix an error from accumarray

accumarray

I have val and subs variables as I shown you and I try to group subs values into same cell array asnd return val to me. When I run this code

    A = accumarray(subs,val,[],@(x) {x})

the Matlab software shows this error "Error using accumarray First input SUBS must contain positive integer subscripts.". Thus, I want to know how can I fix it out ?

Thanks in advance

Best Answer

      A = accumarray(1+subs,val,[],@(x) {x})

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MATLAB: Accumarray error: First input SUBS must contain positive integer subscripts.

[uval,~,subs] = unique(temp_raw_JE50);
accumarray(subs,vals)

You most likely want to accumulate by the unique values. Since these aren't necessarily positive integer indices, use unique first and pass the indices into accumarray.

MATLAB: How to use accumarray

accumarray() can be a bit tricky to learn. I think this solves your problem. I commented it to help you see what is happening.

A = rand(9,5346); % Make up some fake data that is the same size as yours
At = A'; % Take the transpose, because accumarray works down columns.
numberPerGroup = 6;
numberGroups = 5346/6; % 931, but wanted you to see where this comes from
% The subs array indicates which rows (of the transposed array) are going to get grouped. You have 931 groups total, each gather 6 rows.
subs = repmat(1:numberGroups,[numberPerGroup,1]);
subs = subs(:);
% Preallocate the output array
output = zeros(numberGroups,9);
% Accumulate each column in turn
for nr = 1:9
    output(:,nr) = accumarray(subs,At(:,nr),[],@mean);
end
% Transpose the output back
output = output';

Best Answer

Related Solutions

MATLAB: Accumarray error: First input SUBS must contain positive integer subscripts.

MATLAB: How to use accumarray

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