Safe Haskell | None |
---|---|
Language | Haskell2010 |
Set partitions.
Synopsis
- newtype SetPartition = SetPartition [[Int]]
- _standardizeSetPartition :: [[Int]] -> [[Int]]
- fromSetPartition :: SetPartition -> [[Int]]
- toSetPartitionUnsafe :: [[Int]] -> SetPartition
- toSetPartition :: [[Int]] -> SetPartition
- _isSetPartition :: [[Int]] -> Bool
- setPartitionShape :: SetPartition -> Partition
- setPartitions :: Int -> [SetPartition]
- setPartitionsWithKParts :: Int -> Int -> [SetPartition]
- setPartitionsNaive :: Int -> [SetPartition]
- setPartitionsWithKPartsNaive :: Int -> Int -> [SetPartition]
- countSetPartitions :: Int -> Integer
- countSetPartitionsWithKParts :: Int -> Int -> Integer
The type of set partitions
newtype SetPartition Source #
A partition of the set [1..n]
(in standard order)
SetPartition [[Int]] |
Instances
_standardizeSetPartition :: [[Int]] -> [[Int]] Source #
fromSetPartition :: SetPartition -> [[Int]] Source #
toSetPartitionUnsafe :: [[Int]] -> SetPartition Source #
toSetPartition :: [[Int]] -> SetPartition Source #
_isSetPartition :: [[Int]] -> Bool Source #
Forgetting the set structure
setPartitionShape :: SetPartition -> Partition Source #
The "shape" of a set partition is the partition we get when we forget the set structure, keeping only the cardinalities.
Generating set partitions
setPartitions :: Int -> [SetPartition] Source #
Synonym for setPartitionsNaive
setPartitionsWithKParts Source #
:: Int |
|
-> Int |
|
-> [SetPartition] |
Synonym for setPartitionsWithKPartsNaive
sort (setPartitionsWithKParts k n) == sort [ p | p <- setPartitions n , numberOfParts p == k ]
setPartitionsNaive :: Int -> [SetPartition] Source #
List all set partitions of [1..n]
, naive algorithm
setPartitionsWithKPartsNaive Source #
:: Int |
|
-> Int |
|
-> [SetPartition] |
Set partitions of the set [1..n]
into k
parts
countSetPartitions :: Int -> Integer Source #
Set partitions are counted by the Bell numbers