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https://issues.apache.org/jira/browse/TEXT-155?focusedWorklogId=210066&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-210066
]
ASF GitHub Bot logged work on TEXT-155:
---------------------------------------
Author: ASF GitHub Bot
Created on: 08/Mar/19 10:32
Start Date: 08/Mar/19 10:32
Worklog Time Spent: 10m
Work Description: aherbert commented on issue #109: TEXT-155: Add a
generic IntersectionSimilarity measure
URL: https://github.com/apache/commons-text/pull/109#issuecomment-470882543
I'd like to change this a bit to support the `Bag` functionality. One big
nit I had was that:
```
"aa" vs "aa" == 1
"aa" vs "aaaaaaaa" == 1 (with no duplicates)
"aa" vs "aaaaaaaa" == 2 / 8 = 0.25 (with duplicates)
```
I will update the API so that the `Function` is altered to a
`Function<CharSequence, Collection<T>>`. The user just then need to split the
`CharSequence` into a collection. If it is a `Set` then the assumption would be
that the user would like to perform an intersection without duplicates.
Anything else can be converted internally to a `Bag` representation. I'll put
the bag functionality as a private class and only borrow what is needed from
commons-collections. The amount of code will be minimal as it is just a
`HashMap<T, MutableInteger>` so the count of the items in the set can be
adjusted.
This will get it working. If a dependency on commons-collections is not a
problem then the internal class can be removed later without breaking binary
compatibility.
I'll also change F1Score to SorensenDiceCoefficient so the name matches the
parallel work in #103.
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Issue Time Tracking
-------------------
Worklog Id: (was: 210066)
Time Spent: 1h 50m (was: 1h 40m)
> Add a generic SetSimilarity measure
> -----------------------------------
>
> Key: TEXT-155
> URL: https://issues.apache.org/jira/browse/TEXT-155
> Project: Commons Text
> Issue Type: New Feature
> Affects Versions: 1.6
> Reporter: Alex D Herbert
> Priority: Minor
> Time Spent: 1h 50m
> Remaining Estimate: 0h
>
> The {{SimilarityScore<T>}} interface can be used to compute a generic result.
> I propose to add a class that can compute the intersection between two sets
> formed from the characters. The sets must be formed from the {{CharSequence}}
> input to the {{apply}} method using a {{Function<CharSequence, Set<T>>}} to
> convert the {{CharSequence}}. This function can be passed to the
> {{SimilarityScore<T>}} during construction.
> The result can then be computed to have the size of each set and the
> intersection.
> I have created an implementation that can compute the equivalent of the
> {{JaccardSimilary}} class by creating {{Set<Character>}} and also the
> F1-score using bigrams (pairs of characters) by creating {{Set<String>}}.
> This relates to
> [Text-126|https://issues.apache.org/jira/projects/TEXT/issues/TEXT-126] which
> suggested an algorithm for the Sorensen-Dice similarity, also known as the
> F1-score.
> Here is an example:
> {code:java}
> // Match the functionality of the JaccardSimilarity class
> Function<CharSequence, Set<Character>> converter = (cs) -> {
> final Set<Character> set = new HashSet<>();
> for (int i = 0; i < cs.length(); i++) {
> set.add(cs.charAt(i));
> }
> return set;
> };
> IntersectionSimilarity<Character> similarity = new
> IntersectionSimilarity<>(converter);
> IntersectionResult result = similarity.apply("something", "something else");
> {code}
> The result has the size of set A, set B and the intersection between them.
> This class was inspired by my look through the various similarity
> implementations. All of them except the {{CosineSimilarity}} perform single
> character matching between the input {{CharSequence}}s. The
> {{CosineSimilarity}} tokenises using whitespace to create words.
> This more generic type of implementation will allow a user to determine how
> to divide the {{CharSequence}} but to create the sets that are compared, e.g.
> single characters, words, bigrams, etc.
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