MATLAB: HISTCOUNTS a true replacement of HISTC

histchistcountshistogram

Since few latest releases we get the code warning "histc is not recommended. Use histcounts instead".
However how to replace HISTC with specified DIM argument, for example what is the command to get C1 and C2 in this example?
I hope you won't tell me I need a for-loop or some sort disguised loop.
>> A=reshape(linspace(0,1,20),[4 5])
A =
           0    0.2105    0.4211    0.6316    0.8421
      0.0526    0.2632    0.4737    0.6842    0.8947
      0.1053    0.3158    0.5263    0.7368    0.9474
      0.1579    0.3684    0.5789    0.7895    1.0000
>> b=linspace(0,1,3)
b =
           0    0.5000    1.0000
>> c1=histc(A,b,1)
c1 =
       4     4     2     0     0
       0     0     2     4     3
       0     0     0     0     1
>> c2=histc(A,b,2)
c2 =
       3     2     0
       3     2     0
       2     3     0
       2     2     1
>>

Best Answer

Third solution, may be the best in term of speed/memory
    % replacement of [n,i] = histc(x,edges,dim);
    [~,~,i] = histcounts(x, [edges,Inf]);
    s = uint32(size(x));
    nbins = uint32(length(edges)); 
    p1 = uint32(prod(s(1:dim-1)));
    p2 = uint32(prod(s(dim+1:end)));
    if p1 == 1 % happens for dim==1
        k = reshape(uint32(i),[s(dim),p2]);
        l = nbins*(0:p2-1);
        ilin = l + k;
    else
        j = reshape(1:p1,[p1,1,1]);
        k = reshape(uint32(i-1)*p1,[p1,s(dim),p2]);
        l = reshape((p1*nbins)*(0:p2-1),[1,1,p2]);
        ilin = (j + l) + k;
    end
    ilin = ilin(:);
    s(dim) = nbins;
    n = accumarray(ilin(i~=0),1,[prod(s),1]);
    n = reshape(n,s);
EDIT: slight improve code by (1) avoid reduce calculation for dim=1, (2) indexing cast to UINT32
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