Many fail....
Probably all are 32-bit issues as they are fine on 64 bit.
The test cases failing: 156 158 179 189 190 199 200 202 203 205 206.
These will be just skipped on non-OSX platforms. They probably fail because of numeric errors accumulating...
The development of igraph has moved to github, so please do not comment on this bug here. You are of course welcome to comment on github, here: https://github.com/igraph/igraph/issues/454
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Probably all are 32-bit issues as they are fine on 64 bit.