One hot encode column vectors in matrix without iterating - matlab

Question

I am implementing a neural network and am trying to one hot encode a matrix of column vectors based on the max value in each column. Previously, I had been iterating through the matrix vector by vector, but I've been told that this is unnecessary and that I can actually one hot encode every column vector in the matrix at the same time. Unfortunately, after perusing SO, GitHub, and MathWorks, nothing seems to be getting the job done. I've listed my previous code below. Please help! Thanks :)
UPDATE:
This is what I am trying to accomplish...except this only changed the max value in the entire matrix to 1. I want to change the max value in each COLUMN to 1.
one_hots = bsxfun(#eq, mini_batch_activations, max(mini_batch_activations(:)))
UPDATE 2:
This is what I am looking for, but it only works for rows. I need columns.
V = max(mini_batch_activations,[],2);
idx = mini_batch_activations == V;
Iterative code:
% This is the matrix I want to one hot encode
mini_batch_activations = activations{length(layers)};
%For each vector in the mini_batch:
for m = 1:size(mini_batch_activations, 2)
% Isolate column vector for mini_batch
vector = mini_batch_activations(:,m);
% One hot encode vector to compare to target vector
one_hot = zeros(size(mini_batch_activations, 1),1);
[max_val,ind] = max(vector);
one_hot(ind) = 1;
% Isolate corresponding column vector in targets
mini_batch = mini_batch_y{k};
target_vector = mini_batch(:,m);
% Compare one_hot to target vector , and increment result if they match
if isequal(one_hot, target_vector)
num_correct = num_correct + 1;
endif
...
endfor

Answer 1

You’ve got the maxima for each column:
V = max(mini_batch_activations,[],1); % note 1, not 2!
Now all you need to do is equality comparison, the output is a logical array that readily converts to 0s and 1s. Note that MATLAB and Octave do implicit singleton expansion:
one_hot = mini_batch_activations==V;