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faq [2009/05/12 11:55]
hverbeek created
faq [2009/05/12 13:54] (current)
hverbeek
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Yes, Woflan can handle arc weights, but there is a catch. Note that Woflan uses the fact that a free-choice net (or a net that contains no handles) can only be sound if it is S-coverable. This fact holds for nets that do not contain arc weights, but examples with arc weights exist for which this does not hold. Take, for example, the following net: Yes, Woflan can handle arc weights, but there is a catch. Note that Woflan uses the fact that a free-choice net (or a net that contains no handles) can only be sound if it is S-coverable. This fact holds for nets that do not contain arc weights, but examples with arc weights exist for which this does not hold. Take, for example, the following net:
 +------
  place start init 1;   place start init 1;
  place middle;   place middle;
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  trans t1 in start out middle, middle;   trans t1 in start out middle, middle;
  trans t2 in middle, middle out end;   trans t2 in middle, middle out end;
 +
 +------
Woflan will report that this net is not sound due to non-live transitions, but it also reports no non-live transitions. For the former conclusion, it used the fact mentioned above (the net is free-choice, contains no handles, is not S-coverable, is bounded, contains no dead transitions, and is not sound, hence there have to be non-live transitions), for the latter it computed the actual non-live transitions. Woflan will report that this net is not sound due to non-live transitions, but it also reports no non-live transitions. For the former conclusion, it used the fact mentioned above (the net is free-choice, contains no handles, is not S-coverable, is bounded, contains no dead transitions, and is not sound, hence there have to be non-live transitions), for the latter it computed the actual non-live transitions.
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A workaround is to make the net not feee-chocie and add handles, by adding a self-loop transition to some place that may contain multiple tokens: A workaround is to make the net not feee-chocie and add handles, by adding a self-loop transition to some place that may contain multiple tokens:
 +------
  place start init 1;   place start init 1;
  place middle;   place middle;
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  trans t2 in middle, middle out end;   trans t2 in middle, middle out end;
  trans t3 in middle out middle;   trans t3 in middle out middle;
 +
 +------
As a result, Woflan will not use the abovementioned fact, and will report no errors. As a result, Woflan will not use the abovementioned fact, and will report no errors.