Array expressions in Blitz++ are implemented using the expression templates technique. Unless otherwise noted, expression evaluation will never generate temporaries or multiple loops; an expression such as
Array<int,1> A, B, C, D; // ... A = B + C + D;
will result in code similar to
for (int i=A.lbound(firstDim); i <= A.ubound(firstDim); ++i)
A[i] = B[i] + C[i] + D[i];