Data.Vector.Algorithms.Heap

This module implements operations for working with a quaternary heap stored in an unboxed array. Most heapsorts are defined in terms of a binary heap, in which each internal node has at most two children. By contrast, a quaternary heap has internal nodes with up to four children. This reduces the number of comparisons in a heapsort slightly, and improves locality (again, slightly) by flattening out the heap.

Sorting

sort :: (PrimMonad m, MVector v e, Ord e) => v (PrimState m) e -> m ()

Sorts an entire array using the default ordering.

sortBy :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> m ()

Sorts an entire array using a custom ordering.

sortByBounds :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> Int -> m ()

Sorts a portion of an array [l,u) using a custom ordering

Selection

select :: (PrimMonad m, MVector v e, Ord e) => v (PrimState m) e -> Int -> m ()

Moves the lowest k elements to the front of the array. The elements will be in no particular order.

selectBy :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> m ()

Moves the lowest (as defined by the comparison) k elements to the front of the array. The elements will be in no particular order.

selectByBounds :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> Int -> Int -> m ()

Moves the lowest k elements in the portion [l,u) of the array into the positions [l,k+l). The elements will be in no particular order.

Partial sorts

partialSort :: (PrimMonad m, MVector v e, Ord e) => v (PrimState m) e -> Int -> m ()

Moves the lowest k elements to the front of the array, sorted.

partialSortBy :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> m ()

Moves the lowest k elements (as defined by the comparison) to the front of the array, sorted.

partialSortByBounds :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> Int -> Int -> m ()

Moves the lowest k elements in the portion [l,u) of the array into positions [l,k+l), sorted.

Heap operations

heapify :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> Int -> m ()

Constructs a heap in a portion of an array [l, u)

pop :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> Int -> m ()

Given a heap stored in a portion of an array [l,u), swaps the top of the heap with the element at u and rebuilds the heap.

popTo :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> Int -> Int -> m ()

Given a heap stored in a portion of an array [l,u) swaps the top of the heap with the element at position t, and rebuilds the heap.

sortHeap :: (PrimMonad m, MVector v e) => Comparison e -> v (PrimState m) e -> Int -> Int -> Int -> m ()

Given a heap stored in a portion of an array [l,u), sorts the highest values into [m,u). The elements in [l,m) are not in any particular order.

type Comparison e = e -> e -> Ordering

A type of comparisons between two values of a given type.