Explanation of cvSeqPartition()?

I have no idea what this does could someone explain this to me in SIMPLE terms? Please 开发者_Python百科don't give me complicated mathematical answers or something too technical, just its general purpose Thanks

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// This function splits the input sequence or set into one or more equivalence classes.
// is_equal(a,b,...) returns non-zero if the two sequence elements
// belong to the same class.  The function returns sequence of integers -
// 0-based class indexes for each element.
//
// The algorithm is described in "Introduction to Algorithms"
// by Cormen, Leiserson and Rivest, chapter "Data structures for disjoint sets"
CV_IMPL  int
cvSeqPartition( const CvSeq* seq, CvMemStorage* storage, CvSeq** labels,
                CvCmpFunc is_equal, void* userdata )

What part requires more detailed explanation?

Update:

Foe example, consider the following sequence of integers:

{9,5,7,5,9,9}

When is_equal function just tests for integer equality, cvSeqPartition will find 3 classes:

{9,9,9} {5,5} {7}

so cvSeqPartition output will be

{0,1,2,1,0,0}

where each number is index of the element class.