Generate all fruitful variants
The variants are created by generating inflectional variants, spelling variants, acronyms and abbreviations, expansion, derivational variants (recursively), synonyms (recursively), and combinations of these, as specified in Aronson AR, The Effect of Textual Variation on Concept Based Information Retrieval. Proceedings of the AMIA Symposium, 373-377, 1996. This flow option is useful to create an aggressive retrieval index.
The history notation and distance score are shown below:
Operation | Notation | Distance score |
No Operations | n | 0 |
Spelling Variant | s | 0 |
Inflectional Variant | i | 1 |
Uninflectional Variant | b | 1 |
Synonym | y | 2 |
Acronym/Abbreviation | A | 2 |
Expansion | a | 2 |
Derivational Variant | d | 3 |
The algorithm of MetaMap variants are generated by the following combinations:
Derivational variants, Synonyms, Acronyms/Abbreviations, and Expansions are all based on the base form of input. Thus, an uninflect operation needs to be done first. Only suffix derivations are used to generate fruitful variants after 2018.
The output from these combinations are filtered out if they have same spelling and category and kept the one with shortest distance score. Inflections are simplified and only inflections with value less than 256 are kept.
Then, generate spelling variants and inflectional variants (fact and rule) for all items in the above combined list. The spelling variants are generated first since they have lower distance score.
Finally, filter out outputs again by filtering out items with same spelling and category and just keep the one with shortest distance score. In addition, any item with inflection value great than 256 is filtered out.
The -m option include 5 fields to shows detail mutate information:
initial category | category after the very first operation | flow history | distance score | tag information |
The tag information is represented by a long value by combining tag bit values. Currently, two bits are defined as listed in following table:
Bit | Value | Tag |
0 | 1 | Noun/Adj only in recursive derivation |
1 | 2 | Unique acronyms/expansion |
Please refer to Tag class for details.
shell> lvg -f:G -m neurological neurological|nervous systems|128|8|G|1|1|1|n+dd+y+i|9|2| neurological|neurologies|128|8|G|1|1|1|n+d+i|4|3| neurological|neurologists|128|8|G|1|1|1|n+dd+i|7|2| neurological|nervous system|128|1|G|1|1|1|n+dd+y|8|2| neurological|neurology|128|1|G|1|1|1|n+d|3|3| neurological|neurologist|128|1|G|1|1|1|n+dd|6|2| neurological|neurologically|2|1|G|1|1|1|n+d|3|2| neurological|neurol|1|1|G|1|1|1|n+A|2|1| neurological|neurological|1|1|G|1|1|1|n|0|3| neurological|neuro|1|1|G|1|1|1|n+A|2|1| neurological|neurologic|1|1|G|1|1|1|n+y|2|3|More examples