On Thu, 03 Mar 2005 10:52:23 -0800, engsol <[EMAIL PROTECTED]> wrote: > > The diagonal constraint is interesting....it seems to affect the number of > solutions. One surprise, (not being a math major), was that when I let the > brute force run (forever, it seemed), but without the diagonal > qualification(s), > there was maybe 100 solutions. The reson it was a surprise it that years > ago a programmer used the row-sum, col-sum method to detect and correct > data errors. He swore it was robust, and 100% reliable. Seems that that > isn't the case.
I think that it probably is a decent gut-check for data errors, for the simple reason that changing one number requires, at a minimum, three other changes in order to maintain both the row and column sums. If you have at least a decent data fidelity rate, that is unlikely to happen, and even if it does, very very unlikely to happen in such a way that the row and column sums are maintained; especially as the number of rows and columns grows. Better to just do a crc or a hash of the data though. Peace Bill Mill bill.mill at gmail.com -- http://mail.python.org/mailman/listinfo/python-list
