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471 lines
12 KiB
Clojure
471 lines
12 KiB
Clojure
(ns examples.scratch
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(:require [clojure.java.io :as io]
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[clojure.string :as string]
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[clojure.set]
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[com.owoga.prhyme.nlp.core :as nlp]))
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(def re-word
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"Regex for tokenizing a string into words
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(including contractions and hyphenations),
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commas, periods, and newlines."
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#"(?s).*?([a-zA-Z\d]+(?:['\-]?[a-zA-Z]+)?|,|\.|\n)")
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(defn tokenize
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"Tokenizes for suffix trie. First token is end of document."
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[text]
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(->> text
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(re-seq re-word)
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(map second)
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(map string/lower-case)
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(reverse)
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(cons :end)))
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(comment
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(-> (slurp "dev/examples/sandman.txt")
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tokenize))
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(defn zero-to-n-seq
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([coll]
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(zero-to-n-seq coll 1))
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([coll i]
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(let [l (count coll)]
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(if
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(> i l) nil
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(cons (take i coll)
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(lazy-seq (zero-to-n-seq coll (inc i))))))))
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(comment
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(zero-to-n-seq '(1 2 3 4))
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;; => ((1) (1 2) (1 2 3) (1 2 3 4))
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)
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(defn i-to-j-seq
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([coll i j]
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(zero-to-n-seq (->> coll (drop i) (take (- j i))))))
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(defn n-to-zero-seq
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([coll]
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(n-to-zero-seq coll 0))
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([coll i]
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(if (= i (count coll)) nil
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(cons (drop i coll)
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(lazy-seq (n-to-zero-seq coll (inc i)))))))
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(comment
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(n-to-zero-seq '(1 2 3 4))
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;; => ((1 2 3 4) (2 3 4) (3 4) (4))
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)
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(defn add-to-trie [trie coll]
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(update-in trie (concat coll [:count]) (fnil inc 0)))
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(defn add-multiple-to-trie [trie colls]
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(loop [colls colls
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trie trie]
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(cond
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(empty? colls) trie
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:else (recur (rest colls)
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(add-to-trie trie (first colls))))))
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(defn n-gram-suffix-trie
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"Creates a suffix trie of 1-gram to n-gram.
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Useful for backoff language model (I think)."
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[n tokens]
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(let [trie {}
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windows (partition (inc n) 1 tokens)]
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(loop [trie trie
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windows windows]
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(cond
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(= 1 (count windows))
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(add-multiple-to-trie
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trie
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(concat (zero-to-n-seq (first windows))
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(rest (n-to-zero-seq (first windows)))))
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:else
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(recur (add-multiple-to-trie
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trie
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(zero-to-n-seq (first windows)))
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(rest windows))))))
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(comment
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(let [last-window '("in" "the" "frat")]
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(concat (zero-to-n-seq last-window)
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(rest (n-to-zero-seq last-window))))
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;; => (("in") ("in" "the") ("in" "the" "frat") ("the" "frat") ("frat"))
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(n-gram-suffix-trie
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2
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(string/split
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"the cat in the hat is the rat in the frat"
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#" "))
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;; => {"the"
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;; {:count 3,
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;; "cat" {:count 1, "in" {:count 1}},
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;; "hat" {:count 1, "is" {:count 1}},
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;; "rat" {:count 1, "in" {:count 1}},
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;; "frat" {:count 1}},
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;; "cat" {:count 1, "in" {:count 1, "the" {:count 1}}},
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;; "in" {:count 2, "the" {:count 2, "hat" {:count 1}, "frat" {:count 1}}},
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;; "hat" {:count 1, "is" {:count 1, "the" {:count 1}}},
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;; "is" {:count 1, "the" {:count 1, "rat" {:count 1}}},
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;; "rat" {:count 1, "in" {:count 1, "the" {:count 1}}},
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;; "frat" {:count 1}}
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)
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(comment
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(def unigram
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(n-gram-suffix-trie
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1
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(tokenize (slurp "dev/examples/sandman.txt"))))
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unigram
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(->> unigram
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(map (fn [[k v]] (vector k (:count v))))
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(map second)
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(apply +))
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(def bigram
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(n-gram-suffix-trie
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2
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(tokenize (slurp "dev/examples/sandman.txt"))))
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(->> bigram
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(map (fn [[k v]] (vector k (:count v))))
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(map second)
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(apply +))
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(count bigram)
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(->> bigram
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(take 4)
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(into {}))
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;; => {"cutest" {:count 2, "the" {:count 2, "him" {:count 2}}},
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;; "us" {:count 3, "bring" {:count 3, "," {:count 2}, "yeesss" {:count 1}}},
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;; "his" {:count 2, "that" {:count 2, "him" {:count 2}}},
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;; "him"
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;; {:count 8,
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;; "give" {:count 4, "\n" {:count 4}},
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;; "tell" {:count 2, "then" {:count 2}},
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;; "make" {:count 2, "\n" {:count 2}}}}
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(->> bigram
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vals
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(map :count)
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frequencies
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(into [])
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sort
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(map #(apply * %))
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(apply +))
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(count (tokenize (slurp "dev/examples/sandman.txt")))
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;; => ([1 32] [2 20] [3 10] [4 3] [5 1] [6 2] [7 1] [8 2] [9 1] [10 1] [12 1] [26 1])
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)
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(defn P [trie w]
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(let [ws (trie w)
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c (get-in trie [w :count])]
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(->> ws
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(#(dissoc % :count))
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(map
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(fn [[k v]]
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[k (/ (:count v) c)])))))
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(defn vals-or-seconds [m]
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(cond
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(empty? m) m
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(map? m) (apply concat (vals m))
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:else (apply concat (map second m))))
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(defn flat-at-depth
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"Convenience way of getting frequencies of n-grams.
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Given a trie with a depth of 0, it will return all 1-grams key/value pairs.
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That collection can be filtered for keys that hold the freqs."
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[m depth]
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(let [m (if (map? m) (into [] m) m)]
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(cond
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(<= depth 0) m
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:else (flat-at-depth (->> m (mapcat second) (remove #(= :count (first %))))
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(dec depth)))))
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(comment
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(let [trie {"d" {:count 3
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"o" {:count 3
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"g" {:count 2}
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"t" {:count 1}}
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"a" {:count 1
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"y" {:count 1}}}
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"f" {:count 2
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"o" {:count 1
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"g" {:count 1}}
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"i" {:count 1
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"g" {:count 1}}}}]
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(->> (flat-at-depth trie 2)))
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)
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;; Let Nc be the number of N-grams that occur c times.
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;; Good-turing discounting:
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;; c* = (c + 1) * Nc+1 / Nc
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(defn n-gram-frequencies [trie n]
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(if (< n 0)
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{}
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(->> trie
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(#(flat-at-depth % (dec n)))
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(map second)
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(map :count)
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frequencies
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(into (sorted-map)))))
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(defn n-gram->occurence-count-frequencies [trie n]
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(n-gram-frequencies trie n))
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(comment
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(def tokens ["d" "o" "g" "\n" "d" "a" "y" "\n" "d" "o" "g" "\n" "d" "o" "t"])
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(def trie (n-gram-suffix-trie 2 tokens))
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trie
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;; => {"d"
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;; {:count 4,
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;; "o" {:count 3, "g" {:count 2}, "t" {:count 1}},
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;; "a" {:count 1, "y" {:count 1}}},
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;; "o" {:count 2, "g" {:count 2, "\n" {:count 2}}},
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;; "g" {:count 2, "\n" {:count 2, "d" {:count 2}}},
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;; "\n" {:count 3, "d" {:count 3, "a" {:count 1}, "o" {:count 2}}},
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;; "a" {:count 1, "y" {:count 1, "\n" {:count 1}}},
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;; "y" {:count 1, "\n" {:count 1, "d" {:count 1}}}}
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(count bigram)
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(count (flat-at-depth bigram 0))
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(->> bigram
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(#(flat-at-depth % 0))
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(filter #(= :count (first %)))
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(map second)
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frequencies
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(into (sorted-map))
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(map #(apply * %))
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(apply +))
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(n-gram-frequencies trie 2)
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;; => {3 2, 1 3, 2 2}
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;; for bigrams
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;; of frequency 3 occurs 2 times
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;; of frequency 2 occurs 2 times
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;; of frequency 1 occurs 3 times
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(n-gram-frequencies trie 1)
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;; => {4 1, 2 2, 3 1, 1 2}
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)
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(defn num-seen-n-grams [trie n]
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(->> trie
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(#(flat-at-depth % (dec n)))
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(remove #(= :count (first %)))
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count))
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(defn n-gram-frequency-map
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"Map of n-gram to frequency of frequencies."
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[trie n]
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(into
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{}
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(map
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#(vector % (n-gram-frequencies trie %))
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(range 1 (inc n)))))
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(comment
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(n-gram-frequencies bigram 1)
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(n-gram-frequency-map bigram 2)
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)
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(defn number-of-n-grams [trie n]
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(->> trie
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(#(flat-at-depth % (dec n)))
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(remove #(= :count (first %)))
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count))
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(defn number-of-possible-n-grams [dict n]
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(int (Math/pow (count dict) n)))
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(defn number-of-n-grams-that-occur-c-times [trie n c]
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(if (zero? c)
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(- (number-of-possible-n-grams trie n)
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(count (flat-at-depth trie (dec n))))
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(let [frequencies-map (->> (n-gram-frequency-map trie n)
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(#(get % n)))]
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(get frequencies-map c 0))))
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(comment
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(number-of-possible-n-grams bigram 2)
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(count (flat-at-depth bigram 1))
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(count bigram)
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(->> (number-of-n-grams-that-occur-c-times bigram 1 1))
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(->> (number-of-n-grams-that-occur-c-times bigram 0 3)
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(filter #(= :count (first %)))
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(map second)
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frequencies
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sort)
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)
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(defn mle [trie c]
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(let [N (->> trie vals (map :count) (apply +))]
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(/ c N)))
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(->> bigram
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(filter (fn [[k v]] (= 3 (v :count)))))
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;; Good-Turing Smoothing
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;;
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;; There are 4 steps to perform the GT smoothing, which are:
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;; 1. Count the frequency of frequency Nr
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;; 2. Average all the non-zero counts using Zr = Nr / 0.5 (t - q)
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;; 3. Fit a linear regression model log(Zr) = a + b log(r)
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;; 4. Update r with r* using Katz equation and constant k, with
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;; updated Zr corresponding to specific r read out from the linear
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;; regression model.
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(defn least-squares-linear-regression [xs ys]
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(let [n (count xs)
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sum-x (apply + xs)
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sum-y (apply + ys)
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sum-xy (apply + (map #(apply * %) (map vector xs ys)))
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sum-x-sqr (apply + (map #(* % %) xs))
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m (/ (- (* n sum-xy) (* sum-x sum-y))
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(- (* n sum-x-sqr) (* sum-x sum-x)))
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b (/ (- sum-y (* m sum-x)) n)]
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(fn [x]
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(+ (* m x) b))))
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(defn average-consecutives
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"Average all the non-zero counts using the equation
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Zr = Nr / 0.5 (t - q)"
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[freqs Nrs]
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(let [freqs (vec freqs)
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Nrs (vec Nrs)]
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(loop [i 0
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result []]
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(let [q (nth freqs (max (dec i) 0))
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Nr (nth Nrs (min (dec (count freqs)) i))
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r (nth freqs (min (dec (count freqs)) i))
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t (nth freqs (min (dec (count freqs)) (inc i)))]
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(cond
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(= i (count freqs)) result
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(zero? i)
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(recur (inc i)
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(conj result (/ (* 2 Nr) t)))
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(= (dec i) (count freqs))
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(recur (inc i)
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(conj result (/ (* 2 Nr (- t q)))))
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:else
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(recur (inc i)
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(conj result (/ Nr (- r q)))))))))
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(comment
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(let [xs [1 2 3 4 5 6 7 8 9 10 12 26]
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ys [32 20 10 3 1 2 1 1 1 2 1 1]
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smoothed (average-consecutives xs ys)
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logged (map #(Math/log %) smoothed)
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lm (least-squares-linear-regression xs ys)
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log-lm (map lm xs)
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log-ys (map #(Math/pow % Math/E) log-lm)]
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;; => [32 20 10 3 1 2 1 1 1 2 1/2 1/14]
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[log-lm log-ys])
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(Math/log 1)
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)
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(defn turings-estimate [trie n r]
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(/ (* (inc r)
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(number-of-n-grams-that-occur-c-times trie n (inc r)))
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(number-of-n-grams-that-occur-c-times trie n r)))
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(defn good-turing [trie n r]
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(let [nr (number-of-n-grams-that-occur-c-times trie n r)
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nr1 (number-of-n-grams-that-occur-c-times trie n (inc r))]
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(println
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(format "cx %d nc %d ncx1 %d - %f"
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r nr nr1 (float (/ (* (inc r) nr1) nr))))
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(/ (* (inc r) nr1) nr)))
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(comment
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(number-of-n-grams-that-occur-c-times bigram 1 1)
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;; unigram counts
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(def unigram-counts
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(->> bigram
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vals
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(map :count)
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frequencies
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(into (sorted-map))))
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;; => {1 32, 2 20, 3 10, 4 3, 5 1, 6 2, 7 1, 8 1, 9 1, 10 2, 12 1, 26 1}
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;; revised good-turing counts
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(->> unigram-counts
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(map
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(fn [[freq freq']]
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[freq (good-turing bigram 1 freq)]))
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(into (sorted-map)))
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;; => {1 5/4, 2 3/2, 3 6/5, 4 5/3, 5 12, 6 7/2, 7 8, 8 9, 9 20, 10 0, 12 0, 26 0}
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(map (fn [[r nr]]
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(good-turing bigram 1 r))
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unigram-counts)
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;; => (5/4 3/2 6/5 5/3 12 7/2 8 9 20 0 0 0)
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(turings-estimate bigram 1 7)
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)
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(defn revise-frequencies [frequencies N]
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(let [m (reverse (sort (keys frequencies)))]
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(loop [revised {}
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m m]
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(cond
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(empty? m) revised
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:else
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(recur
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(assoc
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revised
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(first m)
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(good-turing (get frequencies (first m) 0)
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(get frequencies (second m) 0)
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N))
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(rest m))))))
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(comment
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(get (n-gram-frequency-map trie 3) 1)
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;; => {4 1, 2 2, 3 1, 1 2}
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(revise-frequencies
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(get (n-gram-frequency-map trie 3) 1)
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(apply + (map :count (vals trie))))
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;; => {4 2/13, 3 4/13, 2 3/13, 1 0}
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(def n-gram-freq-map (n-gram-frequency-map trie 3))
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(def unigram-frequencies (n-gram-freq-map 1))
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unigram-frequencies
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)
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(defn number-of-n-grams-that-occur-with-count [trie n c]
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)
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(defn good-turing-discount [trie c]
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)
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(->> bigram
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(map second))
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(count (into #{} (tokenize (slurp "dev/examples/sandman.txt"))))
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(->> bigram
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(map second)
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(map #(dissoc % :count))
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(map keys)
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flatten
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(into #{})
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(clojure.set/difference (into #{} (keys bigram))))
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(partition 3 1 (repeat :end) (range 6))
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(let [documents (->> "dark-corpus"
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io/file
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file-seq
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(remove #(.isDirectory %))
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(take 10))]
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documents)
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