An array, a, is accessible at a particular point in program execution if it is distributed over a group contained in the active process group:
Informally this means that all copies of all elements of the array are available within the set of processes sharing the current thread of control.
The definition of value-accessibility is slightly more complicated. An
array, a, is value-accessible at a particular point if it is
accessible or if the dimension set of the intersection of
a.grp() with the active process group
contains all process dimensions in a.sig(). This
is a clumsy way of saying that a.grp() may have dimensions
outside the active process group, but the array must be replicated over
those dimensions. A sufficient condition for value-accessibility
is that a be value-aligned to an accessible array.
Informally the meaning of value-accessibility is that at least one copy of every element of the array is available within the set of process sharing the current thread of control.