Virtual Processors
One way to think about DAPPLE collections (vectors and matrices) is
as a set of data elements. Another way to think of them is as a set
of data elements, each of which has a virtual processor for
manipulating that element. Thus, for elementwise operations like
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intVector A(N), B(N), C(N);
...
A = B + C;
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one can imagine the virtual processor at position 3 adding element 3
of B to element 3 of C and then assigning the result to element 3 of
A.
It is often convenient to define
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const intVector VP(N, Identity);
const intMatrix VProw(N, M, IdentityR);
const intMatrix VPcol(N, M, IdentityC);
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for use in expressions that depend on the position, e.g.,
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intVector X(N), Y(N);
...
Y = VP * X; // compute i * x[i], for i = 0 to N-1
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