Copyright | (c) Roman Leshchinskiy 2008-2010 |
---|---|
License | BSD-style |
Maintainer | Roman Leshchinskiy <rl@cse.unsw.edu.au> |
Stability | experimental |
Portability | non-portable |
Safe Haskell | None |
Language | Haskell2010 |
A library for boxed vectors (that is, polymorphic arrays capable of holding any Haskell value). The vectors come in two flavours:
- mutable
- immutable
and support a rich interface of both list-like operations, and bulk array operations.
For unboxed arrays, use Data.Vector.Unboxed
Synopsis
- data Vector a
- data MVector s a
- length :: Vector a -> Int
- null :: Vector a -> Bool
- (!) :: Vector a -> Int -> a
- (!?) :: Vector a -> Int -> Maybe a
- head :: Vector a -> a
- last :: Vector a -> a
- unsafeIndex :: Vector a -> Int -> a
- unsafeHead :: Vector a -> a
- unsafeLast :: Vector a -> a
- indexM :: Monad m => Vector a -> Int -> m a
- headM :: Monad m => Vector a -> m a
- lastM :: Monad m => Vector a -> m a
- unsafeIndexM :: Monad m => Vector a -> Int -> m a
- unsafeHeadM :: Monad m => Vector a -> m a
- unsafeLastM :: Monad m => Vector a -> m a
- slice :: Int -> Int -> Vector a -> Vector a
- init :: Vector a -> Vector a
- tail :: Vector a -> Vector a
- take :: Int -> Vector a -> Vector a
- drop :: Int -> Vector a -> Vector a
- splitAt :: Int -> Vector a -> (Vector a, Vector a)
- uncons :: Vector a -> Maybe (a, Vector a)
- unsnoc :: Vector a -> Maybe (Vector a, a)
- unsafeSlice :: Int -> Int -> Vector a -> Vector a
- unsafeInit :: Vector a -> Vector a
- unsafeTail :: Vector a -> Vector a
- unsafeTake :: Int -> Vector a -> Vector a
- unsafeDrop :: Int -> Vector a -> Vector a
- empty :: Vector a
- singleton :: a -> Vector a
- replicate :: Int -> a -> Vector a
- generate :: Int -> (Int -> a) -> Vector a
- iterateN :: Int -> (a -> a) -> a -> Vector a
- replicateM :: Monad m => Int -> m a -> m (Vector a)
- generateM :: Monad m => Int -> (Int -> m a) -> m (Vector a)
- iterateNM :: Monad m => Int -> (a -> m a) -> a -> m (Vector a)
- create :: (forall s. ST s (MVector s a)) -> Vector a
- createT :: Traversable f => (forall s. ST s (f (MVector s a))) -> f (Vector a)
- unfoldr :: (b -> Maybe (a, b)) -> b -> Vector a
- unfoldrN :: Int -> (b -> Maybe (a, b)) -> b -> Vector a
- unfoldrExactN :: Int -> (b -> (a, b)) -> b -> Vector a
- unfoldrM :: Monad m => (b -> m (Maybe (a, b))) -> b -> m (Vector a)
- unfoldrNM :: Monad m => Int -> (b -> m (Maybe (a, b))) -> b -> m (Vector a)
- unfoldrExactNM :: Monad m => Int -> (b -> m (a, b)) -> b -> m (Vector a)
- constructN :: Int -> (Vector a -> a) -> Vector a
- constructrN :: Int -> (Vector a -> a) -> Vector a
- enumFromN :: Num a => a -> Int -> Vector a
- enumFromStepN :: Num a => a -> a -> Int -> Vector a
- enumFromTo :: Enum a => a -> a -> Vector a
- enumFromThenTo :: Enum a => a -> a -> a -> Vector a
- cons :: a -> Vector a -> Vector a
- snoc :: Vector a -> a -> Vector a
- (++) :: Vector a -> Vector a -> Vector a
- concat :: [Vector a] -> Vector a
- force :: Vector a -> Vector a
- (//) :: Vector a -> [(Int, a)] -> Vector a
- update :: Vector a -> Vector (Int, a) -> Vector a
- update_ :: Vector a -> Vector Int -> Vector a -> Vector a
- unsafeUpd :: Vector a -> [(Int, a)] -> Vector a
- unsafeUpdate :: Vector a -> Vector (Int, a) -> Vector a
- unsafeUpdate_ :: Vector a -> Vector Int -> Vector a -> Vector a
- accum :: (a -> b -> a) -> Vector a -> [(Int, b)] -> Vector a
- accumulate :: (a -> b -> a) -> Vector a -> Vector (Int, b) -> Vector a
- accumulate_ :: (a -> b -> a) -> Vector a -> Vector Int -> Vector b -> Vector a
- unsafeAccum :: (a -> b -> a) -> Vector a -> [(Int, b)] -> Vector a
- unsafeAccumulate :: (a -> b -> a) -> Vector a -> Vector (Int, b) -> Vector a
- unsafeAccumulate_ :: (a -> b -> a) -> Vector a -> Vector Int -> Vector b -> Vector a
- reverse :: Vector a -> Vector a
- backpermute :: Vector a -> Vector Int -> Vector a
- unsafeBackpermute :: Vector a -> Vector Int -> Vector a
- modify :: (forall s. MVector s a -> ST s ()) -> Vector a -> Vector a
- indexed :: Vector a -> Vector (Int, a)
- map :: (a -> b) -> Vector a -> Vector b
- imap :: (Int -> a -> b) -> Vector a -> Vector b
- concatMap :: (a -> Vector b) -> Vector a -> Vector b
- mapM :: Monad m => (a -> m b) -> Vector a -> m (Vector b)
- imapM :: Monad m => (Int -> a -> m b) -> Vector a -> m (Vector b)
- mapM_ :: Monad m => (a -> m b) -> Vector a -> m ()
- imapM_ :: Monad m => (Int -> a -> m b) -> Vector a -> m ()
- forM :: Monad m => Vector a -> (a -> m b) -> m (Vector b)
- forM_ :: Monad m => Vector a -> (a -> m b) -> m ()
- iforM :: Monad m => Vector a -> (Int -> a -> m b) -> m (Vector b)
- iforM_ :: Monad m => Vector a -> (Int -> a -> m b) -> m ()
- zipWith :: (a -> b -> c) -> Vector a -> Vector b -> Vector c
- zipWith3 :: (a -> b -> c -> d) -> Vector a -> Vector b -> Vector c -> Vector d
- zipWith4 :: (a -> b -> c -> d -> e) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e
- zipWith5 :: (a -> b -> c -> d -> e -> f) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f
- zipWith6 :: (a -> b -> c -> d -> e -> f -> g) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f -> Vector g
- izipWith :: (Int -> a -> b -> c) -> Vector a -> Vector b -> Vector c
- izipWith3 :: (Int -> a -> b -> c -> d) -> Vector a -> Vector b -> Vector c -> Vector d
- izipWith4 :: (Int -> a -> b -> c -> d -> e) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e
- izipWith5 :: (Int -> a -> b -> c -> d -> e -> f) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f
- izipWith6 :: (Int -> a -> b -> c -> d -> e -> f -> g) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f -> Vector g
- zip :: Vector a -> Vector b -> Vector (a, b)
- zip3 :: Vector a -> Vector b -> Vector c -> Vector (a, b, c)
- zip4 :: Vector a -> Vector b -> Vector c -> Vector d -> Vector (a, b, c, d)
- zip5 :: Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector (a, b, c, d, e)
- zip6 :: Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f -> Vector (a, b, c, d, e, f)
- zipWithM :: Monad m => (a -> b -> m c) -> Vector a -> Vector b -> m (Vector c)
- izipWithM :: Monad m => (Int -> a -> b -> m c) -> Vector a -> Vector b -> m (Vector c)
- zipWithM_ :: Monad m => (a -> b -> m c) -> Vector a -> Vector b -> m ()
- izipWithM_ :: Monad m => (Int -> a -> b -> m c) -> Vector a -> Vector b -> m ()
- unzip :: Vector (a, b) -> (Vector a, Vector b)
- unzip3 :: Vector (a, b, c) -> (Vector a, Vector b, Vector c)
- unzip4 :: Vector (a, b, c, d) -> (Vector a, Vector b, Vector c, Vector d)
- unzip5 :: Vector (a, b, c, d, e) -> (Vector a, Vector b, Vector c, Vector d, Vector e)
- unzip6 :: Vector (a, b, c, d, e, f) -> (Vector a, Vector b, Vector c, Vector d, Vector e, Vector f)
- filter :: (a -> Bool) -> Vector a -> Vector a
- ifilter :: (Int -> a -> Bool) -> Vector a -> Vector a
- filterM :: Monad m => (a -> m Bool) -> Vector a -> m (Vector a)
- uniq :: Eq a => Vector a -> Vector a
- mapMaybe :: (a -> Maybe b) -> Vector a -> Vector b
- imapMaybe :: (Int -> a -> Maybe b) -> Vector a -> Vector b
- mapMaybeM :: Monad m => (a -> m (Maybe b)) -> Vector a -> m (Vector b)
- imapMaybeM :: Monad m => (Int -> a -> m (Maybe b)) -> Vector a -> m (Vector b)
- catMaybes :: Vector (Maybe a) -> Vector a
- takeWhile :: (a -> Bool) -> Vector a -> Vector a
- dropWhile :: (a -> Bool) -> Vector a -> Vector a
- partition :: (a -> Bool) -> Vector a -> (Vector a, Vector a)
- unstablePartition :: (a -> Bool) -> Vector a -> (Vector a, Vector a)
- partitionWith :: (a -> Either b c) -> Vector a -> (Vector b, Vector c)
- span :: (a -> Bool) -> Vector a -> (Vector a, Vector a)
- break :: (a -> Bool) -> Vector a -> (Vector a, Vector a)
- elem :: Eq a => a -> Vector a -> Bool
- notElem :: Eq a => a -> Vector a -> Bool
- find :: (a -> Bool) -> Vector a -> Maybe a
- findIndex :: (a -> Bool) -> Vector a -> Maybe Int
- findIndices :: (a -> Bool) -> Vector a -> Vector Int
- elemIndex :: Eq a => a -> Vector a -> Maybe Int
- elemIndices :: Eq a => a -> Vector a -> Vector Int
- foldl :: (a -> b -> a) -> a -> Vector b -> a
- foldl1 :: (a -> a -> a) -> Vector a -> a
- foldl' :: (a -> b -> a) -> a -> Vector b -> a
- foldl1' :: (a -> a -> a) -> Vector a -> a
- foldr :: (a -> b -> b) -> b -> Vector a -> b
- foldr1 :: (a -> a -> a) -> Vector a -> a
- foldr' :: (a -> b -> b) -> b -> Vector a -> b
- foldr1' :: (a -> a -> a) -> Vector a -> a
- ifoldl :: (a -> Int -> b -> a) -> a -> Vector b -> a
- ifoldl' :: (a -> Int -> b -> a) -> a -> Vector b -> a
- ifoldr :: (Int -> a -> b -> b) -> b -> Vector a -> b
- ifoldr' :: (Int -> a -> b -> b) -> b -> Vector a -> b
- foldMap :: Monoid m => (a -> m) -> Vector a -> m
- foldMap' :: Monoid m => (a -> m) -> Vector a -> m
- all :: (a -> Bool) -> Vector a -> Bool
- any :: (a -> Bool) -> Vector a -> Bool
- and :: Vector Bool -> Bool
- or :: Vector Bool -> Bool
- sum :: Num a => Vector a -> a
- product :: Num a => Vector a -> a
- maximum :: Ord a => Vector a -> a
- maximumBy :: (a -> a -> Ordering) -> Vector a -> a
- minimum :: Ord a => Vector a -> a
- minimumBy :: (a -> a -> Ordering) -> Vector a -> a
- minIndex :: Ord a => Vector a -> Int
- minIndexBy :: (a -> a -> Ordering) -> Vector a -> Int
- maxIndex :: Ord a => Vector a -> Int
- maxIndexBy :: (a -> a -> Ordering) -> Vector a -> Int
- foldM :: Monad m => (a -> b -> m a) -> a -> Vector b -> m a
- ifoldM :: Monad m => (a -> Int -> b -> m a) -> a -> Vector b -> m a
- foldM' :: Monad m => (a -> b -> m a) -> a -> Vector b -> m a
- ifoldM' :: Monad m => (a -> Int -> b -> m a) -> a -> Vector b -> m a
- fold1M :: Monad m => (a -> a -> m a) -> Vector a -> m a
- fold1M' :: Monad m => (a -> a -> m a) -> Vector a -> m a
- foldM_ :: Monad m => (a -> b -> m a) -> a -> Vector b -> m ()
- ifoldM_ :: Monad m => (a -> Int -> b -> m a) -> a -> Vector b -> m ()
- foldM'_ :: Monad m => (a -> b -> m a) -> a -> Vector b -> m ()
- ifoldM'_ :: Monad m => (a -> Int -> b -> m a) -> a -> Vector b -> m ()
- fold1M_ :: Monad m => (a -> a -> m a) -> Vector a -> m ()
- fold1M'_ :: Monad m => (a -> a -> m a) -> Vector a -> m ()
- sequence :: Monad m => Vector (m a) -> m (Vector a)
- sequence_ :: Monad m => Vector (m a) -> m ()
- prescanl :: (a -> b -> a) -> a -> Vector b -> Vector a
- prescanl' :: (a -> b -> a) -> a -> Vector b -> Vector a
- postscanl :: (a -> b -> a) -> a -> Vector b -> Vector a
- postscanl' :: (a -> b -> a) -> a -> Vector b -> Vector a
- scanl :: (a -> b -> a) -> a -> Vector b -> Vector a
- scanl' :: (a -> b -> a) -> a -> Vector b -> Vector a
- scanl1 :: (a -> a -> a) -> Vector a -> Vector a
- scanl1' :: (a -> a -> a) -> Vector a -> Vector a
- iscanl :: (Int -> a -> b -> a) -> a -> Vector b -> Vector a
- iscanl' :: (Int -> a -> b -> a) -> a -> Vector b -> Vector a
- prescanr :: (a -> b -> b) -> b -> Vector a -> Vector b
- prescanr' :: (a -> b -> b) -> b -> Vector a -> Vector b
- postscanr :: (a -> b -> b) -> b -> Vector a -> Vector b
- postscanr' :: (a -> b -> b) -> b -> Vector a -> Vector b
- scanr :: (a -> b -> b) -> b -> Vector a -> Vector b
- scanr' :: (a -> b -> b) -> b -> Vector a -> Vector b
- scanr1 :: (a -> a -> a) -> Vector a -> Vector a
- scanr1' :: (a -> a -> a) -> Vector a -> Vector a
- iscanr :: (Int -> a -> b -> b) -> b -> Vector a -> Vector b
- iscanr' :: (Int -> a -> b -> b) -> b -> Vector a -> Vector b
- eqBy :: (a -> b -> Bool) -> Vector a -> Vector b -> Bool
- cmpBy :: (a -> b -> Ordering) -> Vector a -> Vector b -> Ordering
- toList :: Vector a -> [a]
- fromList :: [a] -> Vector a
- fromListN :: Int -> [a] -> Vector a
- fromArray :: Array a -> Vector a
- toArray :: Vector a -> Array a
- convert :: (Vector v a, Vector w a) => v a -> w a
- freeze :: PrimMonad m => MVector (PrimState m) a -> m (Vector a)
- thaw :: PrimMonad m => Vector a -> m (MVector (PrimState m) a)
- copy :: PrimMonad m => MVector (PrimState m) a -> Vector a -> m ()
- unsafeFreeze :: PrimMonad m => MVector (PrimState m) a -> m (Vector a)
- unsafeThaw :: PrimMonad m => Vector a -> m (MVector (PrimState m) a)
- unsafeCopy :: PrimMonad m => MVector (PrimState m) a -> Vector a -> m ()
Boxed vectors
Boxed vectors, supporting efficient slicing.
Instances
Monad Vector Source # | |
Functor Vector Source # | |
MonadFix Vector Source # | Instance has same semantics as one for lists Since: 0.12.2.0 |
Defined in Data.Vector | |
MonadFail Vector Source # | Since: 0.12.1.0 |
Defined in Data.Vector | |
Applicative Vector Source # | |
Foldable Vector Source # | |
Defined in Data.Vector fold :: Monoid m => Vector m -> m # foldMap :: Monoid m => (a -> m) -> Vector a -> m # foldMap' :: Monoid m => (a -> m) -> Vector a -> m # foldr :: (a -> b -> b) -> b -> Vector a -> b # foldr' :: (a -> b -> b) -> b -> Vector a -> b # foldl :: (b -> a -> b) -> b -> Vector a -> b # foldl' :: (b -> a -> b) -> b -> Vector a -> b # foldr1 :: (a -> a -> a) -> Vector a -> a # foldl1 :: (a -> a -> a) -> Vector a -> a # elem :: Eq a => a -> Vector a -> Bool # maximum :: Ord a => Vector a -> a # minimum :: Ord a => Vector a -> a # | |
Traversable Vector Source # | |
Eq1 Vector Source # | |
Ord1 Vector Source # | |
Defined in Data.Vector | |
Read1 Vector Source # | |
Defined in Data.Vector | |
Show1 Vector Source # | |
MonadZip Vector Source # | |
Alternative Vector Source # | |
MonadPlus Vector Source # | |
NFData1 Vector Source # | Since: 0.12.1.0 |
Defined in Data.Vector | |
Vector Vector a Source # | |
Defined in Data.Vector basicUnsafeFreeze :: PrimMonad m => Mutable Vector (PrimState m) a -> m (Vector a) Source # basicUnsafeThaw :: PrimMonad m => Vector a -> m (Mutable Vector (PrimState m) a) Source # basicLength :: Vector a -> Int Source # basicUnsafeSlice :: Int -> Int -> Vector a -> Vector a Source # basicUnsafeIndexM :: Monad m => Vector a -> Int -> m a Source # basicUnsafeCopy :: PrimMonad m => Mutable Vector (PrimState m) a -> Vector a -> m () Source # | |
IsList (Vector a) Source # | |
Eq a => Eq (Vector a) Source # | |
Data a => Data (Vector a) Source # | |
Defined in Data.Vector gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Vector a -> c (Vector a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Vector a) # toConstr :: Vector a -> Constr # dataTypeOf :: Vector a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Vector a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Vector a)) # gmapT :: (forall b. Data b => b -> b) -> Vector a -> Vector a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Vector a -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Vector a -> r # gmapQ :: (forall d. Data d => d -> u) -> Vector a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Vector a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Vector a -> m (Vector a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Vector a -> m (Vector a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Vector a -> m (Vector a) # | |
Ord a => Ord (Vector a) Source # | |
Defined in Data.Vector | |
Read a => Read (Vector a) Source # | |
Show a => Show (Vector a) Source # | |
Semigroup (Vector a) Source # | |
Monoid (Vector a) Source # | |
NFData a => NFData (Vector a) Source # | |
Defined in Data.Vector | |
type Mutable Vector Source # | |
Defined in Data.Vector | |
type Item (Vector a) Source # | |
Defined in Data.Vector |
Mutable boxed vectors keyed on the monad they live in (IO
or
).ST
s
Instances
Accessors
Length information
Indexing
unsafeIndex :: Vector a -> Int -> a Source #
O(1) Unsafe indexing without bounds checking
unsafeHead :: Vector a -> a Source #
O(1) First element without checking if the vector is empty
unsafeLast :: Vector a -> a Source #
O(1) Last element without checking if the vector is empty
Monadic indexing
indexM :: Monad m => Vector a -> Int -> m a Source #
O(1) Indexing in a monad.
The monad allows operations to be strict in the vector when necessary. Suppose vector copying is implemented like this:
copy mv v = ... write mv i (v ! i) ...
For lazy vectors, v ! i
would not be evaluated which means that mv
would unnecessarily retain a reference to v
in each element written.
With indexM
, copying can be implemented like this instead:
copy mv v = ... do x <- indexM v i write mv i x
Here, no references to v
are retained because indexing (but not the
elements) is evaluated eagerly.
headM :: Monad m => Vector a -> m a Source #
O(1) First element of a vector in a monad. See indexM
for an
explanation of why this is useful.
lastM :: Monad m => Vector a -> m a Source #
O(1) Last element of a vector in a monad. See indexM
for an
explanation of why this is useful.
unsafeIndexM :: Monad m => Vector a -> Int -> m a Source #
O(1) Indexing in a monad without bounds checks. See indexM
for an
explanation of why this is useful.
unsafeHeadM :: Monad m => Vector a -> m a Source #
O(1) First element in a monad without checking for empty vectors.
See indexM
for an explanation of why this is useful.
unsafeLastM :: Monad m => Vector a -> m a Source #
O(1) Last element in a monad without checking for empty vectors.
See indexM
for an explanation of why this is useful.
Extracting subvectors (slicing)
O(1) Yield a slice of the vector without copying it. The vector must
contain at least i+n
elements.
init :: Vector a -> Vector a Source #
O(1) Yield all but the last element without copying. The vector may not be empty.
tail :: Vector a -> Vector a Source #
O(1) Yield all but the first element without copying. The vector may not be empty.
take :: Int -> Vector a -> Vector a Source #
O(1) Yield at the first n
elements without copying. The vector may
contain less than n
elements in which case it is returned unchanged.
drop :: Int -> Vector a -> Vector a Source #
O(1) Yield all but the first n
elements without copying. The vector may
contain less than n
elements in which case an empty vector is returned.
O(1) Yield a slice of the vector without copying. The vector must
contain at least i+n
elements but this is not checked.
unsafeInit :: Vector a -> Vector a Source #
O(1) Yield all but the last element without copying. The vector may not be empty but this is not checked.
unsafeTail :: Vector a -> Vector a Source #
O(1) Yield all but the first element without copying. The vector may not be empty but this is not checked.
unsafeTake :: Int -> Vector a -> Vector a Source #
O(1) Yield the first n
elements without copying. The vector must
contain at least n
elements but this is not checked.
unsafeDrop :: Int -> Vector a -> Vector a Source #
O(1) Yield all but the first n
elements without copying. The vector
must contain at least n
elements but this is not checked.
Construction
Initialisation
replicate :: Int -> a -> Vector a Source #
O(n) Vector of the given length with the same value in each position
generate :: Int -> (Int -> a) -> Vector a Source #
O(n) Construct a vector of the given length by applying the function to each index
iterateN :: Int -> (a -> a) -> a -> Vector a Source #
O(n) Apply function \(\max(n - 1, 0)\) times to an initial value, producing a vector of length \(\max(n, 0)\). Zeroth element will contain the initial value, that's why there is one less function application than the number of elements in the produced vector.
\( \underbrace{x, f (x), f (f (x)), \ldots}_{\max(0,n)\rm{~elements}} \)
Examples
>>>
import qualified Data.Vector as V
>>>
V.iterateN 0 undefined undefined :: V.Vector String
[]>>>
V.iterateN 4 (\x -> x <> x) "Hi"
["Hi","HiHi","HiHiHiHi","HiHiHiHiHiHiHiHi"]
Since: 0.7.1
Monadic initialisation
replicateM :: Monad m => Int -> m a -> m (Vector a) Source #
O(n) Execute the monadic action the given number of times and store the results in a vector.
generateM :: Monad m => Int -> (Int -> m a) -> m (Vector a) Source #
O(n) Construct a vector of the given length by applying the monadic action to each index
iterateNM :: Monad m => Int -> (a -> m a) -> a -> m (Vector a) Source #
O(n) Apply monadic function \(\max(n - 1, 0)\) times to an initial value, producing a vector of length \(\max(n, 0)\). Zeroth element will contain the initial value, that's why there is one less function application than the number of elements in the produced vector.
For non-monadic version see iterateN
Since: 0.12.0.0
create :: (forall s. ST s (MVector s a)) -> Vector a Source #
Execute the monadic action and freeze the resulting vector.
create (do { v <- new 2; write v 0 'a'; write v 1 'b'; return v }) = <a
,b
>
createT :: Traversable f => (forall s. ST s (f (MVector s a))) -> f (Vector a) Source #
Execute the monadic action and freeze the resulting vectors.
Unfolding
unfoldrExactN :: Int -> (b -> (a, b)) -> b -> Vector a Source #
O(n) Construct a vector with exactly n
elements by repeatedly applying
the generator function to a seed. The generator function yields the
next element and the new seed.
unfoldrExactN 3 (\n -> (n,n-1)) 10 = <10,9,8>
Since: 0.12.2.0
unfoldrExactNM :: Monad m => Int -> (b -> m (a, b)) -> b -> m (Vector a) Source #
O(n) Construct a vector with exactly n
elements by repeatedly
applying the monadic generator function to a seed. The generator
function yields the next element and the new seed.
Since: 0.12.2.0
constructN :: Int -> (Vector a -> a) -> Vector a Source #
O(n) Construct a vector with n
elements by repeatedly applying the
generator function to the already constructed part of the vector.
constructN 3 f = let a = f <> ; b = f <a> ; c = f <a,b> in <a,b,c>
constructrN :: Int -> (Vector a -> a) -> Vector a Source #
O(n) Construct a vector with n
elements from right to left by
repeatedly applying the generator function to the already constructed part
of the vector.
constructrN 3 f = let a = f <> ; b = f<a> ; c = f <b,a> in <c,b,a>
Enumeration
enumFromN :: Num a => a -> Int -> Vector a Source #
O(n) Yield a vector of the given length containing the values x
, x+1
etc. This operation is usually more efficient than enumFromTo
.
enumFromN 5 3 = <5,6,7>
enumFromStepN :: Num a => a -> a -> Int -> Vector a Source #
O(n) Yield a vector of the given length containing the values x
, x+y
,
x+y+y
etc. This operations is usually more efficient than enumFromThenTo
.
enumFromStepN 1 0.1 5 = <1,1.1,1.2,1.3,1.4>
enumFromTo :: Enum a => a -> a -> Vector a Source #
O(n) Enumerate values from x
to y
.
WARNING: This operation can be very inefficient. If at all possible, use
enumFromN
instead.
enumFromThenTo :: Enum a => a -> a -> a -> Vector a Source #
O(n) Enumerate values from x
to y
with a specific step z
.
WARNING: This operation can be very inefficient. If at all possible, use
enumFromStepN
instead.
Concatenation
Restricting memory usage
force :: Vector a -> Vector a Source #
O(n) Yield the argument but force it not to retain any extra memory, possibly by copying it.
This is especially useful when dealing with slices. For example:
force (slice 0 2 <huge vector>)
Here, the slice retains a reference to the huge vector. Forcing it creates a copy of just the elements that belong to the slice and allows the huge vector to be garbage collected.
Modifying vectors
Bulk updates
:: Vector a | initial vector (of length |
-> [(Int, a)] | list of index/value pairs (of length |
-> Vector a |
O(m+n) For each pair (i,a)
from the list, replace the vector
element at position i
by a
.
<5,9,2,7> // [(2,1),(0,3),(2,8)] = <3,9,8,7>
:: Vector a | initial vector (of length |
-> Vector (Int, a) | vector of index/value pairs (of length |
-> Vector a |
O(m+n) For each pair (i,a)
from the vector of index/value pairs,
replace the vector element at position i
by a
.
update <5,9,2,7> <(2,1),(0,3),(2,8)> = <3,9,8,7>
:: Vector a | initial vector (of length |
-> Vector Int | index vector (of length |
-> Vector a | value vector (of length |
-> Vector a |
O(m+min(n1,n2)) For each index i
from the index vector and the
corresponding value a
from the value vector, replace the element of the
initial vector at position i
by a
.
update_ <5,9,2,7> <2,0,2> <1,3,8> = <3,9,8,7>
The function update
provides the same functionality and is usually more
convenient.
update_ xs is ys =update
xs (zip
is ys)
unsafeUpdate :: Vector a -> Vector (Int, a) -> Vector a Source #
Same as update
but without bounds checking.
unsafeUpdate_ :: Vector a -> Vector Int -> Vector a -> Vector a Source #
Same as update_
but without bounds checking.
Accumulations
:: (a -> b -> a) | accumulating function |
-> Vector a | initial vector (of length |
-> [(Int, b)] | list of index/value pairs (of length |
-> Vector a |
O(m+n) For each pair (i,b)
from the list, replace the vector element
a
at position i
by f a b
.
Examples
>>>
import qualified Data.Vector as V
>>>
V.accum (+) (V.fromList [1000.0,2000.0,3000.0]) [(2,4),(1,6),(0,3),(1,10)]
[1003.0,2016.0,3004.0]
:: (a -> b -> a) | accumulating function |
-> Vector a | initial vector (of length |
-> Vector (Int, b) | vector of index/value pairs (of length |
-> Vector a |
O(m+n) For each pair (i,b)
from the vector of pairs, replace the vector
element a
at position i
by f a b
.
Examples
>>>
import qualified Data.Vector as V
>>>
V.accumulate (+) (V.fromList [1000.0,2000.0,3000.0]) (V.fromList [(2,4),(1,6),(0,3),(1,10)])
[1003.0,2016.0,3004.0]
:: (a -> b -> a) | accumulating function |
-> Vector a | initial vector (of length |
-> Vector Int | index vector (of length |
-> Vector b | value vector (of length |
-> Vector a |
O(m+min(n1,n2)) For each index i
from the index vector and the
corresponding value b
from the the value vector,
replace the element of the initial vector at
position i
by f a b
.
accumulate_ (+) <5,9,2> <2,1,0,1> <4,6,3,7> = <5+3, 9+6+7, 2+4>
The function accumulate
provides the same functionality and is usually more
convenient.
accumulate_ f as is bs =accumulate
f as (zip
is bs)
unsafeAccum :: (a -> b -> a) -> Vector a -> [(Int, b)] -> Vector a Source #
Same as accum
but without bounds checking.
unsafeAccumulate :: (a -> b -> a) -> Vector a -> Vector (Int, b) -> Vector a Source #
Same as accumulate
but without bounds checking.
unsafeAccumulate_ :: (a -> b -> a) -> Vector a -> Vector Int -> Vector b -> Vector a Source #
Same as accumulate_
but without bounds checking.
Permutations
unsafeBackpermute :: Vector a -> Vector Int -> Vector a Source #
Same as backpermute
but without bounds checking.
Safe destructive updates
modify :: (forall s. MVector s a -> ST s ()) -> Vector a -> Vector a Source #
Apply a destructive operation to a vector. The operation will be performed in place if it is safe to do so and will modify a copy of the vector otherwise.
modify (\v -> write v 0 'x') (replicate
3 'a') = <'x','a','a'>
Elementwise operations
Indexing
Mapping
imap :: (Int -> a -> b) -> Vector a -> Vector b Source #
O(n) Apply a function to every element of a vector and its index
concatMap :: (a -> Vector b) -> Vector a -> Vector b Source #
Map a function over a vector and concatenate the results.
Monadic mapping
mapM :: Monad m => (a -> m b) -> Vector a -> m (Vector b) Source #
O(n) Apply the monadic action to all elements of the vector, yielding a vector of results
imapM :: Monad m => (Int -> a -> m b) -> Vector a -> m (Vector b) Source #
O(n) Apply the monadic action to every element of a vector and its index, yielding a vector of results
mapM_ :: Monad m => (a -> m b) -> Vector a -> m () Source #
O(n) Apply the monadic action to all elements of a vector and ignore the results
imapM_ :: Monad m => (Int -> a -> m b) -> Vector a -> m () Source #
O(n) Apply the monadic action to every element of a vector and its index, ignoring the results
forM :: Monad m => Vector a -> (a -> m b) -> m (Vector b) Source #
O(n) Apply the monadic action to all elements of the vector, yielding a
vector of results. Equivalent to flip
.mapM
forM_ :: Monad m => Vector a -> (a -> m b) -> m () Source #
O(n) Apply the monadic action to all elements of a vector and ignore the
results. Equivalent to flip
.mapM_
Zipping
zipWith :: (a -> b -> c) -> Vector a -> Vector b -> Vector c Source #
O(min(m,n)) Zip two vectors with the given function.
zipWith3 :: (a -> b -> c -> d) -> Vector a -> Vector b -> Vector c -> Vector d Source #
Zip three vectors with the given function.
zipWith4 :: (a -> b -> c -> d -> e) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e Source #
zipWith5 :: (a -> b -> c -> d -> e -> f) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f Source #
zipWith6 :: (a -> b -> c -> d -> e -> f -> g) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f -> Vector g Source #
izipWith :: (Int -> a -> b -> c) -> Vector a -> Vector b -> Vector c Source #
O(min(m,n)) Zip two vectors with a function that also takes the elements' indices.
izipWith3 :: (Int -> a -> b -> c -> d) -> Vector a -> Vector b -> Vector c -> Vector d Source #
Zip three vectors and their indices with the given function.
izipWith4 :: (Int -> a -> b -> c -> d -> e) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e Source #
izipWith5 :: (Int -> a -> b -> c -> d -> e -> f) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f Source #
izipWith6 :: (Int -> a -> b -> c -> d -> e -> f -> g) -> Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f -> Vector g Source #
zip3 :: Vector a -> Vector b -> Vector c -> Vector (a, b, c) Source #
zip together three vectors into a vector of triples
zip6 :: Vector a -> Vector b -> Vector c -> Vector d -> Vector e -> Vector f -> Vector (a, b, c, d, e, f) Source #
Monadic zipping
zipWithM :: Monad m => (a -> b -> m c) -> Vector a -> Vector b -> m (Vector c) Source #
O(min(m,n)) Zip the two vectors with the monadic action and yield a vector of results
izipWithM :: Monad m => (Int -> a -> b -> m c) -> Vector a -> Vector b -> m (Vector c) Source #
O(min(m,n)) Zip the two vectors with a monadic action that also takes the element index and yield a vector of results
zipWithM_ :: Monad m => (a -> b -> m c) -> Vector a -> Vector b -> m () Source #
O(min(m,n)) Zip the two vectors with the monadic action and ignore the results
izipWithM_ :: Monad m => (Int -> a -> b -> m c) -> Vector a -> Vector b -> m () Source #
O(min(m,n)) Zip the two vectors with a monadic action that also takes the element index and ignore the results
Unzipping
unzip6 :: Vector (a, b, c, d, e, f) -> (Vector a, Vector b, Vector c, Vector d, Vector e, Vector f) Source #
Working with predicates
Filtering
filter :: (a -> Bool) -> Vector a -> Vector a Source #
O(n) Drop elements that do not satisfy the predicate
ifilter :: (Int -> a -> Bool) -> Vector a -> Vector a Source #
O(n) Drop elements that do not satisfy the predicate which is applied to values and their indices
filterM :: Monad m => (a -> m Bool) -> Vector a -> m (Vector a) Source #
O(n) Drop elements that do not satisfy the monadic predicate
mapMaybe :: (a -> Maybe b) -> Vector a -> Vector b Source #
O(n) Drop elements when predicate returns Nothing
imapMaybe :: (Int -> a -> Maybe b) -> Vector a -> Vector b Source #
O(n) Drop elements when predicate, applied to index and value, returns Nothing
mapMaybeM :: Monad m => (a -> m (Maybe b)) -> Vector a -> m (Vector b) Source #
O(n) Apply monadic function to each element of vector and discard elements returning Nothing.
Since: 0.12.2.0
imapMaybeM :: Monad m => (Int -> a -> m (Maybe b)) -> Vector a -> m (Vector b) Source #
O(n) Apply monadic function to each element of vector and its index. Discards elements returning Nothing.
Since: 0.12.2.0
catMaybes :: Vector (Maybe a) -> Vector a Source #
O(n) Return a Vector of all the Just
values.
Since: 0.12.2.0
takeWhile :: (a -> Bool) -> Vector a -> Vector a Source #
O(n) Yield the longest prefix of elements satisfying the predicate. Current implementation is not copy-free, unless the result vector is fused away.
dropWhile :: (a -> Bool) -> Vector a -> Vector a Source #
O(n) Drop the longest prefix of elements that satisfy the predicate without copying.
Partitioning
partition :: (a -> Bool) -> Vector a -> (Vector a, Vector a) Source #
O(n) Split the vector in two parts, the first one containing those
elements that satisfy the predicate and the second one those that don't. The
relative order of the elements is preserved at the cost of a sometimes
reduced performance compared to unstablePartition
.
unstablePartition :: (a -> Bool) -> Vector a -> (Vector a, Vector a) Source #
O(n) Split the vector in two parts, the first one containing those
elements that satisfy the predicate and the second one those that don't.
The order of the elements is not preserved but the operation is often
faster than partition
.
span :: (a -> Bool) -> Vector a -> (Vector a, Vector a) Source #
O(n) Split the vector into the longest prefix of elements that satisfy the predicate and the rest without copying.
break :: (a -> Bool) -> Vector a -> (Vector a, Vector a) Source #
O(n) Split the vector into the longest prefix of elements that do not satisfy the predicate and the rest without copying.
Searching
notElem :: Eq a => a -> Vector a -> Bool infix 4 Source #
O(n) Check if the vector does not contain an element (inverse of elem
)
findIndices :: (a -> Bool) -> Vector a -> Vector Int Source #
O(n) Yield the indices of elements satisfying the predicate in ascending order.
elemIndices :: Eq a => a -> Vector a -> Vector Int Source #
O(n) Yield the indices of all occurences of the given element in
ascending order. This is a specialised version of findIndices
.
Folding
foldl1' :: (a -> a -> a) -> Vector a -> a Source #
O(n) Left fold on non-empty vectors with strict accumulator
foldr1' :: (a -> a -> a) -> Vector a -> a Source #
O(n) Right fold on non-empty vectors with strict accumulator
ifoldl :: (a -> Int -> b -> a) -> a -> Vector b -> a Source #
O(n) Left fold (function applied to each element and its index)
ifoldl' :: (a -> Int -> b -> a) -> a -> Vector b -> a Source #
O(n) Left fold with strict accumulator (function applied to each element and its index)
ifoldr :: (Int -> a -> b -> b) -> b -> Vector a -> b Source #
O(n) Right fold (function applied to each element and its index)
ifoldr' :: (Int -> a -> b -> b) -> b -> Vector a -> b Source #
O(n) Right fold with strict accumulator (function applied to each element and its index)
foldMap :: Monoid m => (a -> m) -> Vector a -> m Source #
O(n) Map each element of the structure to a monoid, and combine
the results. It uses same implementation as corresponding method of
Foldable
type cless. Note it's implemented in terms of foldr
and won't fuse with functions that traverse vector from left to
right (map
, generate
, etc.).
Since: 0.12.2.0
Specialised folds
all :: (a -> Bool) -> Vector a -> Bool Source #
O(n) Check if all elements satisfy the predicate.
Examples
>>>
import qualified Data.Vector as V
>>>
V.all even $ V.fromList [2, 4, 12 :: Int]
True>>>
V.all even $ V.fromList [2, 4, 13 :: Int]
False>>>
V.all even (V.empty :: V.Vector Int)
True
any :: (a -> Bool) -> Vector a -> Bool Source #
O(n) Check if any element satisfies the predicate.
Examples
>>>
import qualified Data.Vector as V
>>>
V.any even $ V.fromList [1, 3, 7 :: Int]
False>>>
V.any even $ V.fromList [3, 2, 13 :: Int]
True>>>
V.any even (V.empty :: V.Vector Int)
False
and :: Vector Bool -> Bool Source #
O(n) Check if all elements are True
Examples
>>>
import qualified Data.Vector as V
>>>
V.and $ V.fromList [True, False]
False>>>
V.and V.empty
True
or :: Vector Bool -> Bool Source #
O(n) Check if any element is True
Examples
>>>
import qualified Data.Vector as V
>>>
V.or $ V.fromList [True, False]
True>>>
V.or V.empty
False
sum :: Num a => Vector a -> a Source #
O(n) Compute the sum of the elements
Examples
>>>
import qualified Data.Vector as V
>>>
V.sum $ V.fromList [300,20,1 :: Int]
321>>>
V.sum (V.empty :: V.Vector Int)
0
product :: Num a => Vector a -> a Source #
O(n) Compute the produce of the elements
Examples
>>>
import qualified Data.Vector as V
>>>
V.product $ V.fromList [1,2,3,4 :: Int]
24>>>
V.product (V.empty :: V.Vector Int)
1
maximum :: Ord a => Vector a -> a Source #
O(n) Yield the maximum element of the vector. The vector may not be empty.
Examples
>>>
import qualified Data.Vector as V
>>>
V.maximum $ V.fromList [2.0, 1.0]
2.0
maximumBy :: (a -> a -> Ordering) -> Vector a -> a Source #
O(n) Yield the maximum element of the vector according to the given comparison function. The vector may not be empty.
minimum :: Ord a => Vector a -> a Source #
O(n) Yield the minimum element of the vector. The vector may not be empty.
Examples
>>>
import qualified Data.Vector as V
>>>
V.minimum $ V.fromList [2.0, 1.0]
1.0
minimumBy :: (a -> a -> Ordering) -> Vector a -> a Source #
O(n) Yield the minimum element of the vector according to the given comparison function. The vector may not be empty.
minIndex :: Ord a => Vector a -> Int Source #
O(n) Yield the index of the minimum element of the vector. The vector may not be empty.
minIndexBy :: (a -> a -> Ordering) -> Vector a -> Int Source #
O(n) Yield the index of the minimum element of the vector according to the given comparison function. The vector may not be empty.
maxIndex :: Ord a => Vector a -> Int Source #
O(n) Yield the index of the maximum element of the vector. The vector may not be empty.
maxIndexBy :: (a -> a -> Ordering) -> Vector a -> Int Source #
O(n) Yield the index of the maximum element of the vector according to the given comparison function. The vector may not be empty.
Monadic folds
ifoldM :: Monad m => (a -> Int -> b -> m a) -> a -> Vector b -> m a Source #
O(n) Monadic fold (action applied to each element and its index)
foldM' :: Monad m => (a -> b -> m a) -> a -> Vector b -> m a Source #
O(n) Monadic fold with strict accumulator
ifoldM' :: Monad m => (a -> Int -> b -> m a) -> a -> Vector b -> m a Source #
O(n) Monadic fold with strict accumulator (action applied to each element and its index)
fold1M :: Monad m => (a -> a -> m a) -> Vector a -> m a Source #
O(n) Monadic fold over non-empty vectors
fold1M' :: Monad m => (a -> a -> m a) -> Vector a -> m a Source #
O(n) Monadic fold over non-empty vectors with strict accumulator
foldM_ :: Monad m => (a -> b -> m a) -> a -> Vector b -> m () Source #
O(n) Monadic fold that discards the result
ifoldM_ :: Monad m => (a -> Int -> b -> m a) -> a -> Vector b -> m () Source #
O(n) Monadic fold that discards the result (action applied to each element and its index)
foldM'_ :: Monad m => (a -> b -> m a) -> a -> Vector b -> m () Source #
O(n) Monadic fold with strict accumulator that discards the result
ifoldM'_ :: Monad m => (a -> Int -> b -> m a) -> a -> Vector b -> m () Source #
O(n) Monadic fold with strict accumulator that discards the result (action applied to each element and its index)
fold1M_ :: Monad m => (a -> a -> m a) -> Vector a -> m () Source #
O(n) Monadic fold over non-empty vectors that discards the result
fold1M'_ :: Monad m => (a -> a -> m a) -> Vector a -> m () Source #
O(n) Monadic fold over non-empty vectors with strict accumulator that discards the result
Monadic sequencing
sequence :: Monad m => Vector (m a) -> m (Vector a) Source #
Evaluate each action and collect the results
Prefix sums (scans)
prescanl' :: (a -> b -> a) -> a -> Vector b -> Vector a Source #
O(n) Prescan with strict accumulator
postscanl' :: (a -> b -> a) -> a -> Vector b -> Vector a Source #
O(n) Scan with strict accumulator
scanl :: (a -> b -> a) -> a -> Vector b -> Vector a Source #
O(n) Haskell-style scan
scanl f z <x1,...,xn> = <y1,...,y(n+1)> where y1 = z yi = f y(i-1) x(i-1)
Example: scanl (+) 0 <1,2,3,4> = <0,1,3,6,10>
scanl' :: (a -> b -> a) -> a -> Vector b -> Vector a Source #
O(n) Haskell-style scan with strict accumulator
scanl1 :: (a -> a -> a) -> Vector a -> Vector a Source #
O(n) Scan over a non-empty vector
scanl f <x1,...,xn> = <y1,...,yn> where y1 = x1 yi = f y(i-1) xi
scanl1' :: (a -> a -> a) -> Vector a -> Vector a Source #
O(n) Scan over a non-empty vector with a strict accumulator
iscanl :: (Int -> a -> b -> a) -> a -> Vector b -> Vector a Source #
O(n) Scan over a vector with its index
Since: 0.12.0.0
iscanl' :: (Int -> a -> b -> a) -> a -> Vector b -> Vector a Source #
O(n) Scan over a vector (strictly) with its index
Since: 0.12.0.0
prescanr' :: (a -> b -> b) -> b -> Vector a -> Vector b Source #
O(n) Right-to-left prescan with strict accumulator
postscanr' :: (a -> b -> b) -> b -> Vector a -> Vector b Source #
O(n) Right-to-left scan with strict accumulator
scanr' :: (a -> b -> b) -> b -> Vector a -> Vector b Source #
O(n) Right-to-left Haskell-style scan with strict accumulator
scanr1 :: (a -> a -> a) -> Vector a -> Vector a Source #
O(n) Right-to-left scan over a non-empty vector
scanr1' :: (a -> a -> a) -> Vector a -> Vector a Source #
O(n) Right-to-left scan over a non-empty vector with a strict accumulator
iscanr :: (Int -> a -> b -> b) -> b -> Vector a -> Vector b Source #
O(n) Right-to-left scan over a vector with its index
Since: 0.12.0.0
iscanr' :: (Int -> a -> b -> b) -> b -> Vector a -> Vector b Source #
O(n) Right-to-left scan over a vector (strictly) with its index
Since: 0.12.0.0
Comparisons
eqBy :: (a -> b -> Bool) -> Vector a -> Vector b -> Bool Source #
O(n) Check if two vectors are equal using supplied equality predicate.
Since: 0.12.2.0
cmpBy :: (a -> b -> Ordering) -> Vector a -> Vector b -> Ordering Source #
O(n) Compare two vectors using supplied comparison function for vector elements. Comparison works same as for lists.
cmpBy compare == compare
Since: 0.12.2.0
Conversions
Lists
Arrays
Other vector types
Mutable vectors
freeze :: PrimMonad m => MVector (PrimState m) a -> m (Vector a) Source #
O(n) Yield an immutable copy of the mutable vector.
thaw :: PrimMonad m => Vector a -> m (MVector (PrimState m) a) Source #
O(n) Yield a mutable copy of the immutable vector.
copy :: PrimMonad m => MVector (PrimState m) a -> Vector a -> m () Source #
O(n) Copy an immutable vector into a mutable one. The two vectors must have the same length.
unsafeFreeze :: PrimMonad m => MVector (PrimState m) a -> m (Vector a) Source #
O(1) Unsafe convert a mutable vector to an immutable one without copying. The mutable vector may not be used after this operation.
unsafeThaw :: PrimMonad m => Vector a -> m (MVector (PrimState m) a) Source #
O(1) Unsafely convert an immutable vector to a mutable one without copying. Note that this is very dangerous function and generally it's only safe to read from resulting vector. In which case immutable vector could be used safely as well.
Problem with mutation happens because GHC has a lot of freedom to
introduce sharing. As a result mutable vectors produced by
unsafeThaw
may or may not share same underlying buffer. For
example:
foo = do let vec = V.generate 10 id mvec <- V.unsafeThaw vec do_something mvec
Here GHC could lift vec
outside of foo which means all calls to
do_something
will use same buffer with possibly disastrous
results. Whether such aliasing happens or not depends on program in
question, optimization levels, and GHC flags.
All in all attempts to modify vector after unsafeThaw falls out of domain of software engineering and into realm of black magic, dark rituals, and unspeakable horrors. Only advice that could be given is: "don't attempt to mutate vector after unsafeThaw unless you know how to prevent GHC from aliasing buffers accidentally. We don't"