Matching tree

For a pair of feature values a similarity value within the range from 0 (dissimilar) to 1 (identical) is calculated. For the comparison of two feature trees, the trees have to be matched against each other. The similarity value of the feature trees results from a weighted average of the similarity values of all matches within the two feature trees to be compared. 

Rarey M, Dixon JS. Feature trees a new molecular similarity measure based on tree matching. / Comput Aided Mol Des 1998 12 471-90. 

Experimental protocol is built into the construction of tree diagrams so that intermediates that are isolated are distinguishable from those that are made in situ, and the order of input dots matches the order of addition of reagents used in the synthesis plan. 

Tree-level matching The double line denotes ip- modes and the single line ip+. 

Figure 4 Tree-level matching Four-Fermi interaction due to hard gluons...

An example of a problem solving tree for the synthesis of Darvon appears in Figure 3. The tree contains both AND nodes and OR nodes (7). The AND branches, connected by double arcs, indicate that both compounds are required to make the compound above them. The OR branches (there are three OR paths to make compound II) indicate different routes for making the compound. The terminal nodes corresponding to starting materials are enclosed in boxes. At present, a branch is terminated when the number of clauses in the clause list, the internal representation of the goal, is less than or equal to six or the clause list matches the clause list of a starting material molecule. 

The undesired event appears as the top event and the trees are drawn from top to bottom. Two basic logic gates connect event blocks the AND-gate and the OR-gate. The facts dictate the structure of the incident diagram and limit the influence of presupposed conclusions invariably drawn by team members before all of the facts are identified and logically matched. Logic rules are used to test the tree structure. 

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