Convert object to array index
ind = subsindex(A)
MATLAB® calls subsindex to convert
an object into an integer index. Define a subsindex method
for your class if you want to use objects of the class as array indices.
ind = subsindex(A) called by MATLAB for
the expression X(A) when A is
an object. MATLAB does not call subsindex if
the indexing expression results in a call to an overloaded subsref or subsasgn method
for the class of 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.
MATLAB invokes subsindex separately
on all the subscripts in an expression, such as X(A,B).