[SRILM User List] Lattice tool crash

[Andreas Stolcke]

On 4/22/2012 7:46 AM, Nickolay V. Shmyrev wrote:
> Hello
>
> lattice tool crashes when trying to read the attached lattice with.
>
> lattice-tool -in-lattice problem.lat -read-htk
>
>   The problem is that it fails to find the final node. So
> finalNode->word on line 1218 in HTK lattice causes access violation.
>
>
Indeed.  Your lattice is missing a end= specification, and the heuristic 
used to determine a final node in this case fails (because your 
de-facto-final node has a self-loop).  The same could happen with the 
start node, if undefined.

The attached patch will issue an error in these cases.  However, you 
should still fix your input lattices (include start/end attributes).

Andreas

-------------- next part --------------
Index: lattice/src/HTKLattice.cc
===================================================================
RCS file: /home/srilm/CVS/srilm/lattice/src/HTKLattice.cc,v
retrieving revision 1.53
diff -c -r1.53 HTKLattice.cc
*** lattice/src/HTKLattice.cc	24 Dec 2011 05:25:54 -0000	1.53
--- lattice/src/HTKLattice.cc	23 Apr 2012 17:27:32 -0000
***************
*** 1164,1169 ****
--- 1164,1171 ----
  	// search for start node: the one without incoming transitions
  	LHashIter<NodeIndex, LatticeNode> nodeIter(nodes);
  	NodeIndex nodeIndex;
+ 
+ 	initialNode = 0;
  	while (LatticeNode *node = nodeIter.next(nodeIndex)) {
  	    if (node->inTransitions.numEntries() == 0) {
  		initial = nodeIndex;
***************
*** 1172,1177 ****
--- 1174,1185 ----
  	    }
  	}
  
+ 	if (!initialNode) {
+ 	    file.position() << "could not find start node\n";
+ 	    if (!useNullNodes) vocab.remove(HTKNodeDummy);
+ 	    return false;
+ 	}
+ 
  	// now find the HTK node info associated with first node
  	LHashIter<unsigned, NodeIndex> nodeMapIter(nodeMap);
  	unsigned htkNode;
***************
*** 1213,1218 ****
--- 1221,1228 ----
  	// search for end node: the one without outgoing transitions
  	LHashIter<NodeIndex, LatticeNode> nodeIter(nodes);
  	NodeIndex nodeIndex;
+ 
+ 	finalNode = 0;
  	while (LatticeNode *node = nodeIter.next(nodeIndex)) {
  	    if (node->outTransitions.numEntries() == 0) {
  		final = nodeIndex;
***************
*** 1221,1226 ****
--- 1231,1242 ----
  	    }
  	}
  
+ 	if (!finalNode) {
+ 	    file.position() << "could not find final node\n";
+ 	    if (!useNullNodes) vocab.remove(HTKNodeDummy);
+ 	    return false;
+ 	}
+ 
  	// now find the HTK node info associated with final node
  	LHashIter<unsigned, NodeIndex> nodeMapIter(nodeMap);
  	unsigned htkNode;