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<H2><A NAME="SECTION02443000000000000000"></A>
<A NAME="2646"></A><A NAME="2647"></A>
<BR>
Independent and borrowed arrays
</H2>
<P>
From a memory perspective, there are two main kinds of arrays:
independent and borrowed. The independent arrays owns and manages its
data. It allocates space for the array elements when the array is
created, and it deallocates that space when the array is finally
destroyed.
<P>
The borrowed array does not own or manage its data. It borrows its
array element data from another source that it cannot manage, and it
only allocates space for the index bounds and stride information. The
rationale for borrowed arrays is to allow data from another source to
temporarily appear as a SIDL array without requiring data be copied.
<P>
If you <TT>slice</TT> an independent array, the resulting array is also
considered independent even though it borrows data from the original
independent array. The resulting array can still manage its data by
retaining a reference to the original array; hence, its element data
cannot disappear until the resulting array is destroyed.
If you <TT>slice</TT> a borrowed array, the resulting array is also
borrowed because like its original array, it doesn't manage the
underlying data.
<P>
In the Babel generated code, r-arrays are converted to borrowed
arrays. These borrowed arrays are allocated on the stack rather than
on the heap to improve performance of r-arrays.
<P>
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