title: How to construct a cross-validation object manually in MATLAB?
body: <p>I have a kind of specific dataset in which several observations (each represented by a separate row) belong to the same object of investigation (e.g. measurements of the same object were performed several times). Each object (and observation) belongs to a certain class. The <strong>problem</strong> is this: it's needed a CV object in which observations are divided partitions and all observations of the same object  belong to the same (either training or validation) partition as a block of data. Unfortunately I'm not sure how to implement this. 
   I  tried to change indices in CV object (cvo), but it seems that the access to some properties such as indices (e.g., cvo.indices) is forbidden.</p>