Subscript indexing with object
ind = subsindex(A)
ind = subsindex(A) called by MATLAB® for the expression X(A) when A is an object, unless such an expression results in a call to an overloaded subsref or subsasgn method for X. subsindex must return the value of the object as a zero-based integer index. (ind must contain integer values in the range 0 to prod(size(X))-1.) Call subsindex directly from an overloaded subsref or subsasgn method.
MATLAB invokes subsindex separately on all the subscripts in an expression, such as X(A,B).