diff --git a/.ghci b/.ghci
new file mode 100644
--- /dev/null
+++ b/.ghci
@@ -0,0 +1,1 @@
+:set -isrc -idist/build/autogen -optP-include -optPdist/build/autogen/cabal_macros.h
diff --git a/.gitignore b/.gitignore
new file mode 100644
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,13 @@
+dist
+docs
+wiki
+TAGS
+tags
+wip
+.DS_Store
+.*.swp
+.*.swo
+*.o
+*.hi
+*~
+*#
diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,12 +1,10 @@
 language: haskell
 before_install:
   # Uncomment whenever hackage is down.
-  # - mkdir -p ~/.cabal && cp config ~/.cabal/config && cabal update
+  # - mkdir -p ~/.cabal && cp travis/config ~/.cabal/config && cabal update
 
   # Try installing some of the build-deps with apt-get for speed.
-  - ./travis-cabal-apt-install --only-dependencies --force-reinstall $mode
-
-  - sudo apt-get -q -y install hlint || cabal install hlint
+  - travis/cabal-apt-install $mode
 
 install:
   - cabal configure -flib-Werror $mode
diff --git a/.vim.custom b/.vim.custom
new file mode 100644
--- /dev/null
+++ b/.vim.custom
@@ -0,0 +1,21 @@
+" Add the following to your .vimrc to automatically load this on startup
+" if filereadable(".vim.custom")
+"     so .vim.custom
+" endif
+
+function StripTrailingWhitespace()
+  let myline=line(".")
+  let mycolumn = col(".")
+  silent %s/  *$//
+  call cursor(myline, mycolumn)
+endfunction
+
+syntax on
+set tags=TAGS;/
+set listchars=tab:‗‗,trail:‗
+set list
+
+map <F2> :exec ":!hasktags -x -c --ignore src"<CR><CR>
+
+au BufWritePre *.hs,*.markdown silent! cal StripTrailingWhitespace()
+au BufWritePost *.hs silent! :exec ":!hasktags -x -c --ignore src"
diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+3.4
+---
+* Added support for `erf` and `inverf`, etc. from `Data.Number.Erf`.
+
 3.3.1
 -----
 * Build system improvements
diff --git a/ad.cabal b/ad.cabal
--- a/ad.cabal
+++ b/ad.cabal
@@ -1,5 +1,5 @@
 name:         ad
-version:      3.3.1.1
+version:      3.4
 license:      BSD3
 license-File: LICENSE
 copyright:    (c) Edward Kmett 2010-2013,
@@ -12,7 +12,16 @@
 bug-reports:  http://github.com/ekmett/ad/issues
 build-type:   Custom
 cabal-version: >= 1.8
-extra-source-files: TODO .travis.yml CHANGELOG.markdown README.markdown
+extra-source-files:
+  .ghci
+  .gitignore
+  .travis.yml
+  .vim.custom
+  TODO
+  CHANGELOG.markdown
+  README.markdown
+  travis/cabal-apt-install
+  travis/config
 synopsis:     Automatic Differentiation
 description:
     Forward-, reverse- and mixed- mode automatic differentiation combinators with a common API.
@@ -61,6 +70,10 @@
     .
     * @0@ means that the resulting derivative list is padded with 0s at the end.
 
+flag lib-Werror
+  default: False
+  manual: True
+
 source-repository head
   type: git
   location: git://github.com/ekmett/ad.git
@@ -91,6 +104,7 @@
     comonad          >= 3,
     containers       >= 0.2 && < 0.6,
     data-reify       >= 0.6 && < 0.7,
+    erf              >= 2.0 && < 2.1,
     free             >= 3,
     mtl              >= 2,
     reflection       >= 1.1.6,
@@ -131,7 +145,12 @@
     Numeric.AD.Internal.Jet
     Numeric.AD.Internal.Identity
 
-  ghc-options: -Wall -fspec-constr -fdicts-cheap -O2
+  if flag(lib-Werror)
+    ghc-options: -Werror
+  else
+    ghc-options: -Wall
+
+  ghc-options: -fspec-constr -fdicts-cheap -O2
 
 -- Verify the results of the examples
 test-suite doctests
diff --git a/src/Numeric/AD/Internal/Classes.hs b/src/Numeric/AD/Internal/Classes.hs
--- a/src/Numeric/AD/Internal/Classes.hs
+++ b/src/Numeric/AD/Internal/Classes.hs
@@ -28,8 +28,9 @@
 
 import Control.Applicative hiding ((<**>))
 import Data.Char
-import Language.Haskell.TH
 import Data.Function (on)
+import Data.Number.Erf
+import Language.Haskell.TH
 
 infixr 8 **!, <**>
 infixl 7 *!, /!, ^*, *^, ^/
@@ -81,6 +82,12 @@
     enumFromThenTo1 :: (Num a, Enum a) => t a -> t a -> t a -> [t a]
     minBound1       :: (Num a, Bounded a) => t a
     maxBound1       :: (Num a, Bounded a) => t a
+    erf1            :: Erf a => t a -> t a
+    erfc1           :: Erf a => t a -> t a
+    normcdf1        :: Erf a => t a -> t a
+    inverf1         :: InvErf a => t a -> t a
+    inverfc1        :: InvErf a => t a -> t a
+    invnormcdf1     :: InvErf a => t a -> t a
 
 class Lifted t => Mode t where
     -- | allowed to return False for items with a zero derivative, but we'll give more NaNs than strictly necessary
@@ -268,8 +275,16 @@
         truncate1 = discrete1 truncate
         round1    = discrete1 round
         ceiling1  = discrete1 ceiling
-        floor1    = discrete1 floor |]
+        floor1    = discrete1 floor
 
+        erf1 = lift1 erf $ \x -> (fromInteger1 2 /! sqrt1 pi1) *! exp1 (negate1 x *! x)
+        erfc1 = lift1 erfc $ \x -> (fromInteger1 (-2) /! sqrt1 pi1) *! exp1 (negate1 x *! x)
+        normcdf1 = lift1 normcdf $ \x -> (fromInteger1 (-1) /! sqrt1 pi1) *! exp1 (x *! x *! fromRational1 (- recip 2) /! sqrt1 (fromInteger1 2))
+
+        inverf1 = lift1 inverfc $ \x -> recip1 $ (fromInteger1 2 /! sqrt1 pi1) *! exp1 (negate1 x *! x)
+        inverfc1 = lift1 inverfc $ \x -> recip1 $ negate1 (fromInteger1 2 /! sqrt1 pi1) *! exp1 (negate1 x *! x)
+        invnormcdf1 = lift1 invnormcdf $ \x -> recip1 $ (fromInteger1 (-1) /! sqrt1 pi1) *! exp1 (x *! x *! fromRational1 (- recip 2) /! sqrt1 (fromInteger1 2)) |]
+
 varA :: Q Type
 varA = varT (mkName "a")
 
@@ -302,7 +317,7 @@
     members <- liftedMembers
     let keep n = nameBase n `elem` members
     xs <- lowerInstance keep ((classP ''Num [varA]:) . f) t `mapM` [''Enum, ''Eq, ''Ord, ''Bounded, ''Show]
-    ys <- lowerInstance keep f                            t `mapM` [''Num, ''Fractional, ''Floating, ''RealFloat,''RealFrac, ''Real]
+    ys <- lowerInstance keep f                            t `mapM` [''Num, ''Fractional, ''Floating, ''RealFloat,''RealFrac, ''Real, ''Erf, ''InvErf]
     return (xs ++ ys)
 
 lowerInstance :: (Name -> Bool) -> ([Q Pred] -> [Q Pred]) -> Q Type -> Name -> Q Dec
diff --git a/src/Numeric/AD/Internal/Composition.hs b/src/Numeric/AD/Internal/Composition.hs
--- a/src/Numeric/AD/Internal/Composition.hs
+++ b/src/Numeric/AD/Internal/Composition.hs
@@ -164,6 +164,12 @@
     enumFromThenTo1 (ComposeMode a) (ComposeMode b) (ComposeMode c) = map ComposeMode $ enumFromThenTo1 a b c
     minBound1 = ComposeMode minBound1
     maxBound1 = ComposeMode maxBound1
+    erf1 (ComposeMode a) = ComposeMode (erf1 a)
+    erfc1 (ComposeMode a) = ComposeMode (erfc1 a)
+    normcdf1 (ComposeMode a) = ComposeMode (normcdf1 a)
+    inverf1 (ComposeMode a) = ComposeMode (inverf1 a)
+    inverfc1 (ComposeMode a) = ComposeMode (inverfc1 a)
+    invnormcdf1 (ComposeMode a) = ComposeMode (invnormcdf1 a)
 
 instance (Typeable1 f, Typeable1 g) => Typeable1 (ComposeMode f g) where
     typeOf1 tfga = mkTyConApp composeModeTyCon [typeOf1 (fa tfga), typeOf1 (ga tfga)]
diff --git a/src/Numeric/AD/Internal/Identity.hs b/src/Numeric/AD/Internal/Identity.hs
--- a/src/Numeric/AD/Internal/Identity.hs
+++ b/src/Numeric/AD/Internal/Identity.hs
@@ -19,13 +19,14 @@
     ) where
 
 import Control.Applicative
-import Numeric.AD.Internal.Classes
-import Numeric.AD.Internal.Types
-import Data.Monoid
 import Data.Data (Data)
+import Data.Foldable (Foldable, foldMap)
+import Data.Monoid
+import Data.Number.Erf
 import Data.Typeable (Typeable)
 import Data.Traversable (Traversable, traverse)
-import Data.Foldable (Foldable, foldMap)
+import Numeric.AD.Internal.Classes
+import Numeric.AD.Internal.Types
 
 newtype Id a = Id { runId :: a } deriving
     (Iso a, Eq, Ord, Show, Enum, Bounded, Num, Real, Fractional, Floating, RealFrac, RealFloat, Monoid, Data, Typeable)
@@ -127,6 +128,12 @@
     enumFromThenTo1 = enumFromThenTo
     minBound1 = minBound
     maxBound1 = maxBound
+    erf1 = erf
+    erfc1 = erfc
+    normcdf1 = normcdf
+    inverf1 = inverf
+    inverfc1 = inverfc
+    invnormcdf1 = invnormcdf
 
 instance Mode Id where
     auto = Id
@@ -137,3 +144,13 @@
 
 instance Primal Id where
     primal (Id a) = a
+
+instance Erf a => Erf (Id a) where
+  erf = Id . erf . runId
+  erfc = Id . erfc . runId
+  normcdf = Id . normcdf . runId
+
+instance InvErf a => InvErf (Id a) where
+  inverf = Id . inverf . runId
+  inverfc = Id . inverfc . runId
+  invnormcdf = Id . invnormcdf . runId
diff --git a/travis/cabal-apt-install b/travis/cabal-apt-install
new file mode 100644
--- /dev/null
+++ b/travis/cabal-apt-install
@@ -0,0 +1,27 @@
+#! /bin/bash
+set -eu
+
+APT="sudo apt-get -q -y"
+CABAL_INSTALL_DEPS="cabal install --only-dependencies --force-reinstall"
+
+$APT update
+$APT install dctrl-tools
+
+# Find potential system packages to satisfy cabal dependencies
+deps()
+{
+	local M='^\([^ ]\+\)-[0-9.]\+ (.*$'
+	local G=' -o ( -FPackage -X libghc-\L\1\E-dev )'
+	local E="$($CABAL_INSTALL_DEPS "$@" --dry-run -v 2> /dev/null \
+		| sed -ne "s/$M/$G/p" | sort -u)"
+	grep-aptavail -n -sPackage \( -FNone -X None \) $E | sort -u
+}
+
+$APT install $(deps "$@") libghc-quickcheck2-dev # QuickCheck is special
+$CABAL_INSTALL_DEPS "$@" # Install the rest via Hackage
+
+if ! $APT install hlint ; then
+	$APT install $(deps hlint)
+	cabal install hlint
+fi
+
diff --git a/travis/config b/travis/config
new file mode 100644
--- /dev/null
+++ b/travis/config
@@ -0,0 +1,16 @@
+-- This provides a custom ~/.cabal/config file for use when hackage is down that should work on unix
+--
+-- This is particularly useful for travis-ci to get it to stop complaining
+-- about a broken build when everything is still correct on our end.
+--
+-- This uses Luite Stegeman's mirror of hackage provided by his 'hdiff' site instead
+--
+-- To enable this, uncomment the before_script in .travis.yml
+
+remote-repo: hdiff.luite.com:http://hdiff.luite.com/packages/archive
+remote-repo-cache: ~/.cabal/packages
+world-file: ~/.cabal/world
+build-summary: ~/.cabal/logs/build.log
+remote-build-reporting: anonymous
+install-dirs user
+install-dirs global