Method Munkres::pair_in_list always return false

[Gluttton]

Method Munkres::pair_in_list always return false.

I have launched tests with option --gtest_repeat=100 and built test coverage report (using lcov). Based report I found that method Munkres::pair_in_list always return false. I have no idea about is this bug or no, but it's looks suspicious. If this method redundant it can be removed, else test case for it must be found.

I have no idea how attach report in issue, so I just attach screenshot.

[saebyn]

I'm not sure - it's been a long while since I wrote that, and I can't find the references I used when I did. I'm thinking that there are some cases where it happens. I agree that some examples of this finding a position of a star or prime that's already been added to the star/prime sequence in a prior pass (the case where pair_in_list would return true) would be helpful.

[Gluttton]

I have checked that if feed to the stage4 matrix which contain loop of STAR and PRIME signs, the function Munkres::pair_in_list will be called. But now is another question how to prove that matrix with loops of STAR and PRIME signs never can be passed into stage4?

Note: matrix with loops of STAR and PRIME signs looks like:
S - P -
- - - -
P - S -
- - - -