The following problem occurs in igraph 0.7.1 for R. I believe there's a
problem with shortest paths computations (e.g., get.all.shortest.paths) due to
imprecise comparison of double types in the C code (e.g., many instances of
"else if (altdist < curdist)" in structural_properties.c). Problems occur if
one's graph contains edge weights like 1/3 (or 0.3333...) and if three of those
are added, their result is not quite 1.0. Should not the "less than" test be
something akin to "if (curdist - altdist > epsilon)" where epsilon is say 1e-8.
(BTW, I read that Knuth suggests a variant that is dependent on the magnitude
of the one of curdist or altdist values). Are there float/double comparisons
in any other places in igraph that might be affected?
Jay
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