1.3.1

• Add missing SplitGen instance for StateGen: #183

1.3.0

• Improve floating point value generation and avoid degenerate cases: #172
• Add Uniform instance for Maybe and Either: #167
• Add Seed, SeedGen, seedSize, seedSizeProxy, mkSeed and unSeed: #162
• Add mkSeedFromByteString, unSeedToByteString, withSeed, withSeedM, withSeedFile, seedGenTypeName, nonEmptyToSeed, nonEmptyFromSeed, withSeedM, withSeedMutableGen and withSeedMutableGen_
• Add SplitGen and splitGen: #160
• Add unifromShuffleList and unifromShuffleListM: #140
• Add uniformWordR: #140
• Add mkStdGen64: #155
• Add uniformListRM, uniformList, uniformListR, uniforms and uniformRs: #154
• Add compatibility with recently added ByteArray to base: #153
  • Switch to using ByteArray for type class implementation instead of ShortByteString
  • Add unsafeUniformFillMutableByteArray to RandomGen and a helper function defaultUnsafeUniformFillMutableByteArray that makes implementation for most instances easier.
  • Add uniformByteArray, uniformByteString and uniformFillMutableByteArray
  • Deprecate genByteString in favor of uniformByteString
  • Add uniformByteArrayM to StatefulGen
  • Add uniformByteStringM and uniformShortByteStringM
  • Deprecate System.Random.Stateful.uniformShortByteString in favor of uniformShortByteStringM for consistent naming and a future plan of removing it from StatefulGen type class
  • Add a pure System.Random.uniformShortByteString generating function.
  • Deprecate genShortByteString in favor of System.Random.uniformShortByteString
  • Expose a helper function fillByteArrayST, that can be used for defining implementation for uniformByteArrayM
  • Deprecate genShortByteStringST and genShortByteStringIO in favor of fillByteArrayST
• Improve FrozenGen interface: #149
  • Move thawGen from FreezeGen into the new ThawGen type class. Fixes an issue with an unlawful instance of StateGen for FreezeGen.
  • Add modifyGen and overwriteGen to the FrozenGen type class
  • Switch splitGenM to use SplitGen and FrozenGen instead of deprecated RandomGenM
  • Add splitMutableGenM
  • Switch randomM and randomRM to use FrozenGen instead of RandomGenM
  • Deprecate RandomGenM in favor of a more powerful FrozenGen
• Add isInRangeOrd and isInRangeEnum that can be used for implementing isInRange: #148
• Add isInRange to UniformRange: #78
• Add default implementation for uniformRM using Generics: #92

1.2.1

• Fix support for ghc-9.2 #99
• Fix performance regression for ghc-9.0 #101
• Add uniformEnumM and uniformEnumRM
• Add initStdGen #103
• Add globalStdGen #117
• Add runStateGenST_
• Ensure that default implementation of ShortByteString generation uses unpinned memory. #116
• Fix #54 with #68 - if exactly one value in the range of floating point is infinite, then uniformRM/randomR returns that value.
• Add default implementation of uniformM that uses Generic #70
• Random instance for CBool #77
• Addition of TGen and TGenM #95
• Addition of tuple instances for Random up to 7-tuple #72

1.2.0

1. Breaking change which mostly maintains backwards compatibility, see “Breaking Changes” below.
2. Support for monadic generators e.g. mwc-random.
3. Monadic adapters for pure generators (providing a uniform monadic interface to pure and monadic generators).
4. Faster in all cases except one by more than x18 (N.B. x18 not 18%) and some cases (depending on the type) faster by more than x1000 - see below for benchmarks.
5. Passes a large number of random number test suites:
   • dieharder
   • TestU01 (SmallCrush, Crush, BigCrush)
   • PractRand
   • gjrand
   • See random-quality for details on how to do this yourself.
6. Better quality split as judged by these tests. Again see random-quality for details on how to do this yourself.
7. Unbiased generation of ranges.
8. Updated tests and benchmarks.
9. Continuous integration.

Breaking Changes

Version 1.2.0 introduces these breaking changes:

• requires base >= 4.8 (GHC-7.10)
• StdGen is no longer an instance of Read
• randomIO and randomRIO were extracted from the Random class into separate functions

In addition, there may be import clashes with new functions, e.g. uniform and uniformR.

Deprecations

Version 1.2.0 introduces genWord64, genWord32 and similar methods to the RandomGen class. The significantly slower method next and its companion genRange are now deprecated.

Issues Addressed

Comments

(*) 1.2 samples more bits but does not sample every Float or Double. There are methods to do this but they have some downsides; see here for a fuller discussion.

Benchmarks

Here are some benchmarks run on a 3.1 GHz Intel Core i7. The full benchmarks can be run using e.g. stack bench. The benchmarks are measured in milliseconds per 100,000 generations. In some cases, the performance is over x1000 times better; the minimum performance increase for the types listed below is more than x36.

1.1

• breaking change to randomIValInteger to improve RNG quality and performance see https://github.com/haskell/random/pull/4 and ghc https://ghc.haskell.org/trac/ghc/ticket/8898
• correct documentation about generated range of Int32 sized values of type Int https://github.com/haskell/random/pull/7
• fix memory leaks by using strict fields and strict atomicModifyIORef’ https://github.com/haskell/random/pull/8 related to ghc trac tickets #7936 and #4218
• support for base < 4.6 (which doesnt provide strict atomicModifyIORef’) and integrating Travis CI support. https://github.com/haskell/random/pull/12
• fix C type in test suite https://github.com/haskell/random/pull/9

1.0.1.1

bump for overflow bug fixes

1.0.1.2

bump for ticket 8704, build fusion

1.0.1.0

bump for bug fixes,

1.0.0.4

bumped version for float/double range bugfix