Reduce graph: added option to remove orphan nodes from WM after reduction (#1735)

* Reduce graph: remove orphan nodes from WM after reduction

* fixed eror

* ignore ids< 0

* add warning and cleanup only when option is used

* updated feedback

* Abort --sync_wm_and_opt_graph if a lot more WM nodes have to be transferred.

* typo

* refactored... completly

* fixed optimized graph cleared

* updated option description

* updated comment

* Added dummy dictionary function to speedup initialization when we dont need the dictionary fully loaded in memory.

* Fixed nodes weight not modified in db when deleted

* Removed AutoUpdate parameter, not needed

* Fixed dummy dictionary usage for detectMoreLoopClosures. Added checks to disable graph reduction when intermediate nodes are detected.

* updated log

tools/DetectMoreLoopClosures/main.cpp

@@ -249,9 +249,15 @@ int main(int argc, char * argv[])
 	UTimer timer;
 	ParametersMap originalParameters = parameters;
 	uInsert(parameters, inputParams);
+
+	// This avoids to load original descriptors in the dictionary
+	// to save RAM and intialization time (we don't need the dictionary for this tool)
+	rtabmap.setDummyDictionary(true); // should be set before Rtabmap::init()
+	
 	rtabmap.init(parameters, dbPath);
 	printf("Initialization... done! (%f sec)\n", timer.ticks());
 
+	// detectMoreLoopClosures would clear the optimized map if loop closures are detected
 	float xMin, yMin, cellSize;
 	bool haveOptimizedMap = !rtabmap.getMemory()->load2DMap(xMin, yMin, cellSize).empty();
 
@@ -311,7 +317,7 @@ int main(int argc, char * argv[])
 	// Restore original parameters before saving back the database
 	rtabmap.parseParameters(originalParameters);
 
-	rtabmap.close();
+	rtabmap.close(detected>0);
 
-	return 0;
+	return detected>=0;
 }