Execution time bottleneck: How to speed up execution?

[Doug Gwyn]

In article <64745 at brunix.UUCP> gvr at cs.brown.edu (George V. Reilly) writes:
-In article <15884.27b919a3 at levels.sait.edu.au> marwk at levels.sait.edu.au (Ray)
-writes:
-> (1) rewrite the sum as Sum = 2 * S{i=1,i=n-1} S{j=i+1,j=n} f(i,j)
->     this cuts the number of calculations in half.
-I can make no sense of this statement.  It's not equivalent to
-the original code.

The idea was right, but he handled the diagonal incorrectly.