Class HollowTrieDistributor<T>

  • All Implemented Interfaces:
    it.unimi.dsi.fastutil.Function<T,​java.lang.Long>, it.unimi.dsi.fastutil.objects.Object2LongFunction<T>, it.unimi.dsi.fastutil.Size64, java.io.Serializable, java.util.function.Function<T,​java.lang.Long>, java.util.function.ToLongFunction<T>

    public class HollowTrieDistributor<T>
    extends it.unimi.dsi.fastutil.objects.AbstractObject2LongFunction<T>
    implements it.unimi.dsi.fastutil.Size64
    A distributor based on a hollow trie.

    Implementation details

    This class implements a distributor on top of a hollow trie. First, a compacted trie is built from the delimiter set. Then, for each key we compute the node of the trie in which the bucket of the key is established. This gives us, for each node of the trie, a set of paths to which we must associate an action (exit on the left, go through, exit on the right). Overall, the number of such paths is equal to the number of keys plus the number of delimiters, so the mapping from each pair node/path to the respective action takes linear space. Now, from the compacted trie we just retain a hollow trie, as the path-length information is sufficient to rebuild the keys of the above mapping. By sizing the bucket size around the logarithm of the average length, we obtain a distributor that occupies linear space.

    See Also:
    Serialized Form
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected double meanSkipLength
      The average skip length in bits (actually, the average length in bits of a skip length increased by one).
      • Fields inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2LongFunction

        defRetValue
    • Constructor Summary

      Constructors 
      Constructor Description
      HollowTrieDistributor​(java.lang.Iterable<? extends T> elements, int log2BucketSize, it.unimi.dsi.bits.TransformationStrategy<? super T> transformationStrategy)
      Creates a partial compacted trie using given elements, bucket size and transformation strategy.
      HollowTrieDistributor​(java.lang.Iterable<? extends T> elements, int log2BucketSize, it.unimi.dsi.bits.TransformationStrategy<? super T> transformationStrategy, java.io.File tempDir)
      Creates a hollow trie distributor.
    • Method Summary

      All Methods Instance Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      double bitsPerSkip()  
      boolean containsKey​(java.lang.Object o)  
      long getLong​(java.lang.Object o)  
      long numBits()  
      int size()
      Deprecated.
      long size64()  
      • Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractObject2LongFunction

        defaultReturnValue, defaultReturnValue
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
      • Methods inherited from interface it.unimi.dsi.fastutil.Function

        apply, clear
      • Methods inherited from interface java.util.function.Function

        compose
      • Methods inherited from interface it.unimi.dsi.fastutil.objects.Object2LongFunction

        andThen, andThenByte, andThenChar, andThenDouble, andThenFloat, andThenInt, andThenLong, andThenObject, andThenReference, andThenShort, applyAsLong, composeByte, composeChar, composeDouble, composeFloat, composeInt, composeLong, composeObject, composeReference, composeShort, get, getOrDefault, getOrDefault, put, put, remove, removeLong
    • Field Detail

      • meanSkipLength

        protected double meanSkipLength
        The average skip length in bits (actually, the average length in bits of a skip length increased by one).
    • Constructor Detail

      • HollowTrieDistributor

        public HollowTrieDistributor​(java.lang.Iterable<? extends T> elements,
                                     int log2BucketSize,
                                     it.unimi.dsi.bits.TransformationStrategy<? super T> transformationStrategy)
                              throws java.io.IOException
        Creates a partial compacted trie using given elements, bucket size and transformation strategy.
        Parameters:
        elements - the elements among which the trie must be able to rank.
        log2BucketSize - the logarithm of the size of a bucket.
        transformationStrategy - a transformation strategy that must turn the elements in elements into a list of distinct, lexicographically increasing (in iteration order) bit vectors.
        Throws:
        java.io.IOException
      • HollowTrieDistributor

        public HollowTrieDistributor​(java.lang.Iterable<? extends T> elements,
                                     int log2BucketSize,
                                     it.unimi.dsi.bits.TransformationStrategy<? super T> transformationStrategy,
                                     java.io.File tempDir)
                              throws java.io.IOException
        Creates a hollow trie distributor.
        Parameters:
        elements - the elements among which the trie must be able to rank.
        log2BucketSize - the logarithm of the size of a bucket.
        transformationStrategy - a transformation strategy that must turn the elements in elements into a list of distinct, lexicographically increasing (in iteration order) bit vectors.
        tempDir - the directory where temporary files will be created, or for the default directory.
        Throws:
        java.io.IOException
    • Method Detail

      • getLong

        public long getLong​(java.lang.Object o)
        Specified by:
        getLong in interface it.unimi.dsi.fastutil.objects.Object2LongFunction<T>
      • numBits

        public long numBits()
      • containsKey

        public boolean containsKey​(java.lang.Object o)
        Specified by:
        containsKey in interface it.unimi.dsi.fastutil.Function<T,​java.lang.Long>
      • size64

        public long size64()
        Specified by:
        size64 in interface it.unimi.dsi.fastutil.Size64
      • size

        @Deprecated
        public int size()
        Deprecated.
        Specified by:
        size in interface it.unimi.dsi.fastutil.Function<T,​java.lang.Long>
        Specified by:
        size in interface it.unimi.dsi.fastutil.Size64
      • bitsPerSkip

        public double bitsPerSkip()