> All,
>
> I'm hoping another, wiser set of eyes can help me to see what I'm doing wrong.
>
> I've defined a deftype below that stores a likelihood and a tree structure
> (nested vectors). The deftype overrides equals, etc, and implements
> Comparable so I can add SearchResults to a sorted-set and sort by likelihood.
> Equal SearchResults have the same likelihood and have quasi-isomorphic tree
> structures.
>
> (deftype SearchResult [lik tree]
> Object
> (toString [sr]
> (str lik ":" tree))
> (equals [sr other]
> (and (= lik (.lik other)) (quasi-isomorphic? tree (.tree other))))
> (hashCode [sr]
> (int lik))
>
> Comparable
> (compareTo [sr sr2]
> (cond
> (= sr sr2) 0
> (> (.lik sr) (.lik sr2)) -1
> :default 1)))
>
> I've defined some dummy data, which should illustrate the unusual behavior
> I'm seeing when I add SearchResults to a sorted-set.
>
> user> (def t1 [{:name 0} [{:name 1} [{:name 3}] [{:name 2}]] [{:name 4}]])
> user> (def t2 [{:name 0} [{:name 1} [{:name 2}] [{:name 3}]] [{:name 4}]])
> user> (def t3 [{:name 0} [{:name 1} [{:name 4}] [{:name 2}]] [{:name 3}]])
> user> (def t4 [{:name 0} [{:name 1} [{:name 4}] [{:name 3}]] [{:name 2}]])
> user> (quasi-isomorphic? t1 t2)
> true
> user> (quasi-isomorphic? t1 t3)
> false
> user> (quasi-isomorphic? t1 t4)
> false
> user> (def sr1 (SearchResult. 1 t1))
> user> (def sr2 (SearchResult. 1 t2))
> user> (def sr3 (SearchResult. 1 t3))
> user> (def sr4 (SearchResult. 1 t4))
> user> (= sr1 sr2)
> true
> user> (= sr1 sr3)
> false
> user> (= sr1 sr4)
> false
> user> (def ss (sorted-set))
> true
> user> (count (conj ss sr1 sr3 sr4 sr2))
> 4
> user> (count (conj ss sr1 sr2 sr3 sr4))
> 3
>
> Of the four SearchResults, only sr1 and sr2 should be equal per the equals
> and compareTo functions defined in SearchResult. Based on that assumption, I
> thought that evaluating (conj ss sr1 sr3 sr4 sr2) would only return a set
> containing sr1, sr3, sr4, but it actually returns a set containing all four
> SearchResults. However, if I change the order of the SearchResults, as in
> (conj ss sr1 sr2 sr3 sr4), it works as expected, returning the set
> containing sr1, sr3, sr4.
>
> I've tried debugging the equals function to see what, exactly, is being
> compared, and it looks like in (conj ss sr1 sr3 sr4 sr2), sr2 is never
> actually compared to sr1, so sr2 gets added to the set. What am I missing?
>
> Any help would be greatly appreciated.
>
> -Travis
>
> p.s. Yes, the hashCode function isn't the best, but from what I could read,
> it does fulfill the requirements of the contract outlined in the javadocs.
Hi Travis,
In order for this to work, the "quasi-isomorphic?" function has be reflexive.
Is it? (The .equals implementation is also missing a type test, but that
probably isn't the problem here.)
You should also try using a TreeSet and see if you get the same results as with
sorted-set.
Cheers,
Stu
Stuart Halloway
Clojure/core
http://clojure.com
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