| Stability | experimental |
|---|---|
| Maintainer | Patrick Perry <patperry@stanford.edu> |
Data.Permutation
Contents
Description
- data Permutation
- permutation :: Int -> [Int] -> Permutation
- identity :: Int -> Permutation
- inverse :: Permutation -> Permutation
- size :: Permutation -> Int
- apply :: Permutation -> Int -> Int
- applyWith :: Monad m => (Int -> Int -> m ()) -> Permutation -> m ()
- invertWith :: Monad m => (Int -> Int -> m ()) -> Permutation -> m ()
- fromForeignPtr :: Int -> ForeignPtr Int -> Int -> Permutation
- toForeignPtr :: Permutation -> (Int, ForeignPtr Int, Int)
- toList :: Permutation -> [Int]
- fromList :: [Int] -> Permutation
- withPermutationPtr :: Permutation -> (Ptr Int -> IO a) -> IO a
- unsafePermutation :: Int -> [Int] -> Permutation
- unsafeApply :: Permutation -> Int -> Int
The Permutation type
Creating permutations
permutation :: Int -> [Int] -> PermutationSource
Create a permutation from a list of values. The list must be of length
n and contain each integer in {0, 1, ..., (n-1) } exactly once.
The permutation that is returned will send the integer i to its index
in the list.
identity :: Int -> PermutationSource
Create an identity permutation of the given size.
inverse :: Permutation -> PermutationSource
Get the inverse of a permutation.
Permutation properties
size :: Permutation -> IntSource
Get the size of the permutation.
apply :: Permutation -> Int -> IntSource
Apply a permutation to an integer. The integer must be in the range
[0..n).
Applying permutations
applyWith :: Monad m => (Int -> Int -> m ()) -> Permutation -> m ()Source
applyWith swap perm applies the permutation as a sequence of swaps. After
this function is applied, OUT[i] = IN[P[i]]
invertWith :: Monad m => (Int -> Int -> m ()) -> Permutation -> m ()Source
invertWith swap p applies the inverse of the permutation as a
sequence of swaps. After this function is applied, OUT[P[i]] = IN[i]
Converstion to/from other types
ForeignPtrs
fromForeignPtr :: Int -> ForeignPtr Int -> Int -> PermutationSource
Convert size and raw array to a permutation. No validation is performed on the arguments.
toForeignPtr :: Permutation -> (Int, ForeignPtr Int, Int)Source
Get the size, raw data array and offset
Lists
toList :: Permutation -> [Int]Source
fromList :: [Int] -> PermutationSource
Unsafe operations
withPermutationPtr :: Permutation -> (Ptr Int -> IO a) -> IO aSource
Perform an operation, given a pointer to the start of the permutation data
unsafePermutation :: Int -> [Int] -> PermutationSource
Same as permutation, but does not check that the inputs are valid.
unsafeApply :: Permutation -> Int -> IntSource
Same as apply but does not range-check the argument.