Indeed. Highlights for me were the large number of people involved, and seeing two new members (Howard S and goooders) get actively involved for the first time. Also, it was good to see Glyn contributing again. Special thanks to Cathy for getting the ball rolling. Thanks also to Andrew for offering to consolidate our steps, which were fairly chaotic in some places! . I'm sure Ed is regretting not having been able to take part in the action...Andrew wrote:Yes, a great team effort.
Edit: the above paragraph is beginning to sound like part of a speech at an award ceremony!
Yes, it was considerably harder than the V1, because of the very narrow solving paths. However, it was no monster. I would give it a clear rating of 1.75. In other words, about the same as the A60RP-Lite, which also had several forum members stumped. It's definitely not as hard as the A62V2 was, which I could eventually solve without hypotheticals, but only by using several grouped AICs. (BTW, I rated the A62V2 at 2.0. Haven't posted the WT for it yet, but plan to do so soon.)Andrew wrote:I'll be interested to see what rating Ed eventually comes up with for this puzzle; it's clearly much, much harder than A64.
Yes, we did use hypotheticals (several of them, me included!), but only because (having looked at how JS (JSudoku) and SS (SudokuSolver) did it) we missed a couple of critical moves that would have allowed us to complete the puzzle without any limited T&E whatsoever. JS found one, SS (which took a completely different path) found the other. Either one would have sufficed to break the deadlock, but unfortunately we found neither.
By condensed, I assume you mean what I usually refer to as optimized? In other words, where some steps (not on the solving path) may be dropped, and others re-ordered in order to ensure a more logical and coherent build-up, etc.Andrew wrote:If as Mike suggested early on, this one might have a very narrow solving path, then a consolidated WT is probably almost the same as a condensed WT.
However, I would like to clarify something here. When I refer to the narrowness of a solving path, I'm referring to the situation without the use of any T&E-based techniques. As soon as one is prepared to use hypotheticals (as we did), then the number of possible solution paths skyrockets. For example, there may be only a couple of ways to solve this particular puzzle without T&E, but we could probably have found dozens of hypothetical chains leading to a conflict, given enough time. Thus, a consolidated WT in this case is not the same as a condensed/optimized WT, because merely completing the puzzle does not imply that we found (or were even close to finding) the optimum solving path.
BTW, the path taken by SS was particularly impressive. Gone are the days where we were regularly out-gunning the automated solvers! With the advent of SS and the quantum leap made by the new version of JS, the tables are often turned, and the solver logs can teach us a thing or two. From SS's point-of-view, this puzzle really was as easy as the low rating suggests. As I think I've said before, computer-based ratings can at best only reflect the difficulty level of the solving path they used to solve the puzzle. But if a human misses this path, and cannot easily find another way through, the perceived difficulty can be much higher. The trouble is, how does one objectively measure the narrowness of the solution paths and the resulting impact on the ergonomics of a puzzle?
That's all for now. If anybody's interested, I plan to make another post describing the moves that we missed, with some extra information and ideas for Ed and his ratings.