BSD3 licensed by Edward A. Kmett
Maintained by Edward A. Kmett

Module documentation for 0.9.3

There are no documented modules for this package.


Hackage Build Status

What rolls down stairs alone or in pairs Rolls over your neighbor’s dog? What’s great for a snack and fits on your back? It’s Log, Log, Log!

It’s Log, Log, it’s big, it’s heavy, it’s wood. It’s Log, Log, it’s better than bad, it’s good! Everyone wants a log! You’re gonna love it, Log! Come on and get your log! Everyone needs a Log!”

– Ren & Stimpy, The Log Song

This package provides log-domain floats, doubles and complex numbers.

Contact Information

Contributions and bug reports are welcome!

Please feel free to contact me through github or on the #haskell IRC channel on

-Edward Kmett



  • Drop safecopy support
  • Removed some unused constraints.


  • Support doctest-0.12


  • Revamp Setup.hs to use cabal-doctest. This makes it build with Cabal-2.0, and makes the doctests work with cabal new-build and sandboxes.


  • Replace use of Hashable1 from hashable-extras in favor of Hashable from hashable- As a result, the hashable-extras dependency has been removed.
  • On Windows, we now use the FFI to link against the C math library if building with GHC 8.0 or later, which features a much improved runtime linker story.
  • Remove generic-deriving dependency

  • Support safecopy 0.9


  • Work around an issue with safecopy on GHC 7.10
  • Changed the repository link to my ekmett github account from analytics.

  • Add vector 0.11 support.


  • Add generic-deriving 1.8 support. We also no longer incur a generic-deriving dependency at all on GHC 7.6+

  • Compiles warning-free on GHC 7.10


  • semigroupoids 5 support.

  • Improved the stability and portability of the doctest test suite


  • (**) is now much more accurately defined.
  • We now avoid comparisons for equality with infinities.
  • Fixed a bug in negate.
  • On windows we avoid FFI into the math library, and accept less accurate results. (Sorry!)


  • Fixed subtraction again. For real this time.

  • Support generic-deriving 1.7


  • Fixed subtraction better.


  • Fixed subtraction.


  • Updated to comonad and semigroupoids 4.


  • Dependency bump to allow comonad and semigroupoids 4.0


  • Marked Numeric.Log Trustworthy.


  • Renamed the data constructor to Exp and the field accessor to ln per issue #1.

  • Wider bounds for generic-deriving so we can build with GHC HEAD.


  • Switched the Hashable1 instance to use the new, lighter, hashable-extras


  • instance Hashable1 Log

  • Wider binary version bound


  • Added support for cereal.


  • Added an Enum instance.
  • Added sum to calculate using the log-sum-exp trick.

  • Minor packaging changes


  • Renamed from log to log-domain due to internal hackage issues rendering that name inaccessible.
  • Ported Numeric.Log from analytics at the request of @bgamari
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