[Lemon-user] Infinity loop problem with CycleCanceling

[Alpár Jüttner]

FYI, a ticket has been created about this issue:

https://lemon.cs.elte.hu/trac/lemon/ticket/403

It would be nice if you could post there a simple code reproducing this
problem.

Regards,
Alpar

On Tue, 2011-01-04 at 11:13 +0100, meistermicha at gmx.de wrote:
> Hello,
> I am using the lemon library 1.2.1 to solve a minCostFlow-problem. I encountered a problem by using the cyclecanceling algorithm. Sometimes, depending on graph and flow settings, the function hangs in an infinity loop at cycle_canceling.h at line 935:
> 
> while (mmc.findCycleMean() && mmc.cycleCost() < 0) {
> 
> I do not have deep insight into the algorithm but by debugging I saw that mmc.cycleCost() returns constantly values around -10e-17. Everything seems to work correctly by changing the line to
> 
> while (mmc.findCycleMean() && mmc.cycleCost() < -10e-10) {
> 
> Maybe this is a rounding issue?
> 
> Regards,
> Michael