Ruud and
Ocean, thanks for the feedback.
Ruud wrote:In your example, row 8 will lock candidates in box 7.
- Code: Select all
/ . . | . . . | . . /
/ . . | . . . | . . /
X * * | * * * | * * X
---------+----------+----------
X * * | . . . | * * X
X * * | . . . | * * X
/ X X | / / / | X X /
---------+----------+----------
*X * * | . . . | . . /
/ X X | / / / | / / /
*X * * | . . . | . . /
[edit by ronk: r79c1 were '*' only]
Had the locked candidates been a rattlesnake, I'd probably be dead.
"Extra" exclusions always seem to be an issue with degenerate (non-minimal, non-viable, composite, superimposed, remora, ???) fish. I favor continuing to show only the exclusions provided by the single-step and adding a footnote that points out the smaller fish. Then this exemplar would look something like ...
- Code: Select all
/ . . | . . . | . . / * . . | . . . | . . *
/ . . | . . . | . . / * . . | . . . | . . *
X * * | * * * | * * X X / / | / / / | / / X
---------+----------+---------- ---------+----------+----------
X * * | . . . | * * X X / / | . . . | / / X
X * * | . . . | * * X X / / | . . . | / / X
/ X X | / / / | X X / *X X X | * * * | X X *X
---------+----------+---------- ---------+----------+----------
X * * | . . . | . . / X / / | . . . | . . *
/ X X | / / / | / / / *X X X | * * * | * * *
X * * | . . . | . . / X / / | . . . | . . *
Fig n: rrcc\rbbb Fig n inverse: rbbb\rrcc
rrcc\cbbb transpose cbbb\rrcc transpose
mutant jellyfish
Only exclusions from the single step are shown. Separately applying locked candidates and a mutant swordfish in the left and right figures, respectively, yields two additional exclusions not shown.
For the "original" (left figure), a r\b 1-fish (locked candidates) yields two exclusions which then reveals a rcc\rbb swordfish -- for a two-step approach that produces two more exclusions than the single-step rrcc\rbbb jellyfish. For the inverse, a rbb\rcc swordfish yields the same two additional exclusions which then reveals a b\r 1-fish.
Frankly, from the standpoint of an exemplar catalog these degenerate fish are a big pain in the tush. Fundamentally, they are an overlay of two or more smaller fish ... and there probably are far too many such combinations to make cataloging them all practical. Cataloging a few examples to illustrate their usefulness is the best I'm hoping for at this point.
How is a degenerate fish useful? I see them as useful when one or more fins are added ... such as in the following example where a fin makes the "opening" locked candidate r8\b7 unavailable.
Ruud wrote:- Code: Select all
/ . . | . . . | . . /
/ . . | . . . | . . /
X . . | . . . | . . X
---------+----------+----------
X * * | . . . | . . X
X * * | . . . | . . X
# X X | / / / | X / /
---------+----------+----------
X . . | . . . | . . /
/ X X | / / / | # / /
X . . | . . . | . . /
[edited by ronk to show fins]
This generalization is a kraken fish from an actual puzzle posted on the Kraken Fish thread
here.
Ruud wrote:I cannot relate this to a finned fish, but a little extended grouped coloring explains these eliminations:
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/ . . | . . . | . . /
/ . . | . . . | . . /
-b . . | . . . | . . B
---------+----------+----------
B * * | . . . | . . -b
B * * | . . . | . . -b
. A A | / / / | B / /
---------+----------+----------
-b . . | . . . | . . /
/ B B | / / / | -b / /
-b . . | . . . | . . /
That's pretty much Greek to me and there's also a candidate in r6c1. Since exactly one candidate in c1 must be true, it sort of looks like ...
r456c1-x-r45c23,
r3c1-x-r3c9=x=r45c9-x-r6c7=x=r6c123-x-r45c23 and
r79c1-x-r8c23=x=r8c7-x-r6c7=x=r6c123-x-r45c23
... but I can't make the connection, particularly the '-b' in two different boxes of c1 and the 'A' without an 'a' anywhere. Is this notation from the Programmers' Forum?
[edit" OK, I think I see. The 'A's are a "starting point" and assumed to be false. Then coloring shows all candidates in c1 eliminated ... except for the 'B's. Cells r45c23 see all the 'A's in r6 and all the 'B's in c1 and hence candidates in r45c23 may be safely excluded.
That would seem easier to understand than kraken jellyfish.]