Help please simulation of gibbs sampling isempty function?

i make a simulation to a gibbs sampling algorithm and the following code is part of the simulation :

   mamodel=@(x)find(ismember(x(:,2:end),[1 0 0 0 0],'rows'))
    if~isempty(a)
        macount=a(mamodel(a),:)
    else
        macount=zeros(1,size(a,2))
    end
    h(i,:)=(macount)

the first line is to find a certain row from simulation results the problem is when this row is not in the results the smulation stops because the result is Empty matrix: 0-by-6 , i tried isempty function and also the simulation stops!! i want to make the simulation ignore the results and continue to next step

[Walter Roberson]

Please retag. http://www.mathworks.co.uk/matlabcentral/answers/43073-a-guide-to-tags

Answer 1

[Walter Roberson]

When I look at your anonymous function it appears to me that it could potentially return a variable number of results, leading to macount being an array rather than a column vector. You would then get a dimension mismatch when assigning it to h(i,:)

Since you need a result which is the same number of rows as h has, use zeros(1,size(h,2)). Unless, that is, you did not predefine h, in which case for your first execution, you would not have an "h" to take the size of.