Find Max value with index
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Hello All, I have two vectors of size (100x1) named "groups" and "norms", groups vector contains labels such as
groups=[1 2 2 1 3 2 3]
and norms vector contains length of vectors that belongs to one of the groups.
norms=[0.4923 0.6023 0.5717 0.4296 0.5425 0.5101 0.5185]
Now I want to find the max value of norms in each group with their corresponding index position in norms vector. I have the following code which gets the max norm in each group but it does not return index.
maxs = accumarray(groups(:,1), norms(:,1), [], @max);
Any help will be appreciated. Thanks.
回答（1 个）
Rik
2018-3-8
Your current code doesn't return a maximum value for each group. The code below should do what you need.
groups=[1 2 2 1 3 2 3];
norms=[0.4923 0.6023 0.5717 0.4296 0.5425 0.5101 0.5185];
grouplist=unique(groups);
num=numel(grouplist);
maxs=zeros(num,1);
maxs_idx=zeros(num,1);
for idx=1:num
[maxs(idx),maxs_idx(idx)]=max(norms(groups==grouplist(idx)));
end
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