diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright Marco Zocca (c) 2017
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Marco Zocca nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,34 @@
+# matrix-market-attoparsec
+
+[![Build Status](https://travis-ci.org/ocramz/matrix-market-attoparsec.png)](https://travis-ci.org/ocramz/matrix-market-attoparsec)
+
+Attoparsec parser for the NIST Matrix Market format [1].
+
+The library also contains functions for serializing to text file, and the read/write/read roundtrip works as expected.
+
+## User guide
+
+The module `Data.Matrix.MatrixMarket` exports the user interface:
+
+
+    readMatrix :: FilePath -> IO (Matrix S.Scientific)
+
+    readArray :: FilePath -> IO (Array S.Scientific)
+
+    writeMatrix :: Show a => FilePath -> Matrix a -> IO ()
+ 
+    writeArray :: Show a => FilePath -> Array a -> IO ()  
+
+The first two functions contain the parsing logic, and make use of `scientific` for parsing numerical data in scientific notation.
+
+`test/LibSpec.hs` contains a simple read/write/read sanity test:
+
+    m0 <- readMatrix fname   -- load original
+    writeMatrix ftemp m0     -- save as temp
+    m1 <- readMatrix ftemp   -- load temp
+    m0 `shouldBe` m1         -- compare temp with original
+
+
+## References
+
+[1] [http://math.nist.gov/MatrixMarket/](http://math.nist.gov/MatrixMarket/)
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/data/fidapm05.mtx b/data/fidapm05.mtx
new file mode 100644
--- /dev/null
+++ b/data/fidapm05.mtx
@@ -0,0 +1,522 @@
+%%MatrixMarket matrix coordinate real general
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+8 39  2.6666666666667e-02
+9 39  1.2000000000000e-01
+17 39 -2.7755575615629e-16
+18 39 -3.3306690738755e-16
+39 39  0.0000000000000e+00
+41 39 -2.6666666666667e-02
+42 39 -1.2000000000000e-01
+6 40  1.1111111111111e-01
+7 40 -6.6613381477509e-15
+8 40  1.1111111111111e-01
+15 40 -3.5555555555555e-01
+16 40 -1.0666666666666e+00
+17 40 -3.5555555555553e-01
+24 40 -2.0000000000004e-01
+34 40 -1.3333333333333e-01
+35 40 -2.2222222222222e-02
+36 40 -9.3333333333331e-02
+40 40  1.9555555555555e+00
+41 40 -1.9999999999998e-01
+6 41 -2.2222222222222e-02
+7 41  1.1111111111112e-01
+8 41 -6.6666666666668e-02
+9 41  1.1111111111111e-01
+15 41  1.1111111111111e-01
+16 41 -3.5555555555558e-01
+17 41 -3.9999999999997e-01
+18 41 -3.5555555555555e-01
+24 41 -3.3333333333329e-02
+34 41 -3.3333333333334e-02
+35 41 -5.5555555555555e-03
+36 41 -2.6666666666667e-02
+37 41 -3.3333333333334e-02
+38 41 -5.5555555555556e-03
+39 41 -2.6666666666667e-02
+40 41 -1.9999999999998e-01
+41 41  1.2444444444445e+00
+42 41 -2.0000000000005e-01
+8 42  1.1111111111111e-01
+9 42  3.1086244689504e-15
+17 42 -3.5555555555551e-01
+18 42 -1.0666666666667e+00
+37 42 -1.3333333333333e-01
+38 42 -2.2222222222222e-02
+39 42 -1.2000000000000e-01
+41 42 -2.0000000000005e-01
+42 42  1.9555555555556e+00
diff --git a/data/fidapm05_rhs1.mtx b/data/fidapm05_rhs1.mtx
new file mode 100644
--- /dev/null
+++ b/data/fidapm05_rhs1.mtx
@@ -0,0 +1,44 @@
+%%MatrixMarket matrix array real general
+42 1
+ 2.6666666666667e-02
+ 1.3333333333334e-02
+ 2.6666666666667e-02
+ 1.3333333333333e-02
+ 2.6666666666667e-02
+ 1.3333333333333e-02
+ 2.6666666666666e-02
+ 1.3333333333334e-02
+ 2.6666666666667e-02
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
+ 0.0000000000000e+00
diff --git a/matrix-market-attoparsec.cabal b/matrix-market-attoparsec.cabal
new file mode 100644
--- /dev/null
+++ b/matrix-market-attoparsec.cabal
@@ -0,0 +1,61 @@
+name:                matrix-market-attoparsec
+version:             0.1.0.0
+synopsis:            Attoparsec parsers for the NIST Matrix Market format
+description:         Please see README.md
+homepage:            https://github.com/ocramz/matrix-market-attoparsec
+license:             BSD3
+license-file:        LICENSE
+author:              Marco Zocca
+maintainer:          zocca marco gmail
+copyright:           2017 Marco Zocca
+category:            Parsers
+build-type:          Simple
+extra-source-files:  README.md
+data-dir:            data
+data-files:          fidapm05.mtx
+                     fidapm05_rhs1.mtx                     
+cabal-version:       >=1.10
+tested-with:         GHC == 8.0.1
+
+
+                     
+library
+  default-language:    Haskell2010
+  ghc-options:         -Wall
+  hs-source-dirs:      src
+  exposed-modules:     Data.Matrix.MatrixMarket
+  other-modules:       Data.Matrix.MatrixMarket.Internal
+                       Control.Exception.Common
+  build-depends:       attoparsec  >= 0.10
+                     , base        >= 4.7 && < 5
+                     , bytestring  >= 0.9
+                     , directory
+                     , exceptions
+                     , scientific  >= 0.3.4.9
+                     , vector      >= 0.7
+
+-- executable matrix-market-attoparsec
+--   default-language:    Haskell2010
+--   ghc-options:         -threaded -rtsopts -with-rtsopts=-N
+--   hs-source-dirs:      app
+--   main-is:             Main.hs
+--   build-depends:       base
+--                      , matrix-market-attoparsec
+
+test-suite spec
+  default-language:    Haskell2010
+  ghc-options:         -Wall
+  type:                exitcode-stdio-1.0
+  hs-source-dirs:      test
+  main-is:             Spec.hs
+  other-modules:       LibSpec
+  build-depends:       QuickCheck
+                     , base
+                     , exceptions
+                     , directory
+                     , hspec
+                     , matrix-market-attoparsec
+
+source-repository head
+  type:     git
+  location: https://github.com/ocramz/matrix-market-attoparsec
diff --git a/src/Control/Exception/Common.hs b/src/Control/Exception/Common.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Exception/Common.hs
@@ -0,0 +1,11 @@
+module Control.Exception.Common where
+
+import Control.Exception
+import Control.Monad.Catch (MonadThrow (..))
+import Data.Typeable -- (TypeRep, Typeable, typeRep)
+
+
+data ImportError = FileParseError String String deriving (Eq, Typeable)
+instance Show ImportError where
+  show (FileParseError s s2) = unwords [s, ": File parse error:", s2]
+instance Exception ImportError
diff --git a/src/Data/Matrix/MatrixMarket.hs b/src/Data/Matrix/MatrixMarket.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Matrix/MatrixMarket.hs
@@ -0,0 +1,3 @@
+module Data.Matrix.MatrixMarket (module M) where
+
+import Data.Matrix.MatrixMarket.Internal as M
diff --git a/src/Data/Matrix/MatrixMarket/Internal.hs b/src/Data/Matrix/MatrixMarket/Internal.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Matrix/MatrixMarket/Internal.hs
@@ -0,0 +1,324 @@
+{-# LANGUAGE GADTs, OverloadedStrings, DeriveFunctor #-}
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Matrix.MatrixMarket.Internal
+-- Copyright   :  (c) Marco Zocca 2017
+-- License     :  GPL-style (see the file LICENSE)
+--
+-- Maintainer  :  zocca marco gmail
+-- Stability   :  experimental
+-- Portability :  portable
+--
+-- Attoparsec parser and serializer for the NIST MatrixMarket format. The parser logic originally appeared in `accelerate-examples` and it is reused here (courtesy of T.McDonell and the `accelerate` developers) with some amendments.
+-- 
+-- In this version:
+-- *) Numbers are represented with Scientific notation instead of floating point
+-- *) Parsing rules are a bit relaxed to accommodate various whitespace corner cases
+--
+-----------------------------------------------------------------------------
+module Data.Matrix.MatrixMarket.Internal
+       (readMatrix, readArray,
+        writeMatrix, writeArray,
+        Matrix(..), Array(..),
+        Format (Coordinate, Array), Structure (General, Symmetric, Hermitian, Skew),
+        nnz, dim, numDat,
+        dimArr, numDatArr) where
+
+
+
+import Control.Applicative                      hiding ( many )
+
+import Data.Int
+import qualified Data.Char as C
+import Data.Complex
+import qualified Data.Scientific as S
+import Data.Attoparsec.ByteString.Char8 hiding (I)
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Lazy.Char8 as B
+import qualified Data.Attoparsec.Lazy           as L
+import qualified Data.ByteString.Lazy           as L
+
+import Control.Monad.Catch
+import Control.Exception.Common
+
+
+
+-- | Specifies either sparse or dense storage.  In sparse (\"coordinate\")
+-- storage, elements are given in (i,j,x) triplets for matrices (or (i,x) for
+-- vectors).  Indices are 1-based, so that A(1,1) is the first element of a
+-- matrix, and x(1) is the first element of a vector.
+--
+-- In dense (\"array\") storage, elements are given in column-major order.
+--
+-- In both cases, each element is given on a separate line.
+--
+data Format = Coordinate | Array
+    deriving (Eq, Show)
+
+-- | Specifies the element type.  Pattern matrices do not have any elements,
+-- only indices, and only make sense for coordinate matrices and vectors.
+--
+data Field  = R | C | I | P
+    deriving (Eq, Show)
+             
+
+-- | Specifies any special structure in the matrix.  For symmetric and hermitian
+-- matrices, only the lower-triangular part of the matrix is given. For skew
+-- matrices, only the entries below the diagonal are stored.
+--
+data Structure = General | Symmetric | Hermitian | Skew
+    deriving (Eq, Show)
+
+
+-- | Sparse matrix in coordinate form (row, column, entry)
+-- NB: indices are 1-based i.e. A(1,1) is the top-left entry of matrix A
+data Matrix a = RMatrix (Int, Int) Int Structure [(Int, Int, a)]
+              | CMatrix (Int, Int) Int Structure [(Int, Int, Complex a)]
+              | PatternMatrix (Int,Int) Int  Structure [(Int32,Int32)]
+              | IntMatrix (Int,Int) Int Structure [(Int32,Int32,Int)]
+              deriving (Eq, Show)
+
+
+
+-- | Array, i.e. a DENSE matrix (also used to represent vectors as n-by-1 matrices)
+data Array a = RArray (Int, Int) Structure [a]
+             | CArray (Int, Int) Structure [Complex a]
+             deriving (Eq, Show)
+
+
+
+
+
+
+--------------------------------------------------------------------------------
+-- Attoparsec combinators
+--------------------------------------------------------------------------------
+
+comment :: Parser ()
+comment = char '%' *> skipWhile (not . eol) *> endOfLine
+  where
+    eol w = w `elem` ("\n\r" :: String)
+
+floating :: Parser S.Scientific
+floating = skipSpace' *> scientific
+
+integral :: Integral a => Parser a
+integral = skipSpace' *> decimal
+
+format :: Parser Format
+format =  string "coordinate" *> pure Coordinate
+      <|> string "array"      *> pure Array
+      <?> "matrix format"
+
+field :: Parser Field
+field =  string "real"    *> pure R
+     <|> string "complex" *> pure C
+     <|> string "integer" *> pure I
+     <|> string "pattern" *> pure P
+     <?> "matrix field"
+
+structure :: Parser Structure
+structure =  string "general"        *> pure General
+         <|> string "symmetric"      *> pure Symmetric
+         <|> string "hermitian"      *> pure Hermitian
+         <|> string "skew-symmetric" *> pure Skew
+         <?> "matrix structure"
+
+header :: Parser (Format,Field,Structure)
+header =  string "%%MatrixMarket matrix"
+       >> (,,) <$> (skipSpace' *> format)
+               <*> (skipSpace' *> field)
+               <*> (skipSpace' *> structure)
+               <*  endOfLine
+               <?> "MatrixMarket header"
+
+extentMatrix :: Parser (Int,Int,Int)
+extentMatrix = do
+  [m,n,l] <- skipSpace' *> count 3 integral <* endOfLine
+  return (m,n,l)
+
+extentArray :: Parser (Int,Int)
+extentArray = do
+  [m,n] <- skipSpace' *> count 2 integral <* endOfLine
+  return (m,n)
+
+line3 :: Integral i => Parser a -> Parser (i,i,a)
+line3 f = (,,) <$> integral
+               <*> integral
+               <*> f
+               <*  endOfLine
+
+skipSpace' :: Parser String
+skipSpace' = many' space
+
+
+--------------------------------------------------------------------------------
+-- Load and parse
+--------------------------------------------------------------------------------
+
+matrix :: Parser (Matrix S.Scientific)
+matrix = do
+  (f, t, s) <- header
+  (m, n, l) <- skipMany comment *> extentMatrix
+  if f /= Coordinate
+    then fail "matrix is not in Coordinate format"
+    else
+    case t of 
+     R -> RMatrix (m,n) l s <$> many1 (line3 floating)
+     C -> CMatrix (m,n) l s <$> many1 (line3 ((:+) <$> floating <*> floating))
+     I -> IntMatrix     (m,n) l s <$> many1 (line3 integral)
+     P -> PatternMatrix (m,n) l s <$> many1 ((,) <$> integral <*> integral)
+
+array :: Parser (Array S.Scientific)
+array = do
+  (f, t, s) <- header
+  (m, n) <- skipMany comment *> extentArray
+  if f /= Array
+    then fail "array is not in Array format"
+    else
+     case t of
+       R -> RArray (m,n) s <$> many1 floating
+       C -> CArray (m,n) s <$> many1 ((:+) <$> floating <*> floating)
+       _ -> fail "integer and pattern cases not relevant for the dense case"
+
+
+-- | Load a matrix (sparse, i.e. in Coordinate format) from file
+readMatrix :: FilePath -> IO (Matrix S.Scientific)
+readMatrix file = do
+  chunks <- L.readFile file
+  case L.parse matrix chunks of
+    L.Fail _ _ msg      -> throwM (FileParseError "readMatrix" msg)
+    L.Done _ mtx        -> return mtx
+
+-- | Load a dense matrix (i.e. a matrix or vector in Array format) from file
+readArray :: FilePath -> IO (Array S.Scientific)
+readArray file = do
+  chunks <- L.readFile file
+  case L.parse array chunks of
+    L.Fail _ _ msg      -> throwM (FileParseError "readArray" msg)
+    L.Done _ mtx        -> return mtx
+
+
+--------------------------------------------------------------------------------
+-- Write to file
+--------------------------------------------------------------------------------
+
+showFormat :: Format -> String
+showFormat = map C.toLower <$> show
+
+showField :: Field -> String
+showField f = case f of R -> "real"
+                        C -> "complex"
+                        I -> "integer"
+                        P -> "pattern"
+
+showStruct :: Structure -> String
+showStruct = map C.toLower <$> show
+
+-- %%MatrixMarket matrix coordinate real general
+
+headerStr :: Format -> Field -> Structure -> L.ByteString
+headerStr f t s =
+    B.pack $ unwords ["%%MatrixMarket matrix",
+                      showFormat f, showField t, showStruct s]
+
+
+nl :: L.ByteString
+nl = toLBS "\n" 
+
+showLines :: (a -> String) -> [a] -> L.ByteString
+showLines showf d = L.concat (L.pack . withNewline . showf <$> d) where
+  withNewline x = toEnum . C.ord <$> x ++ "\n"
+
+
+
+-- | Serialize a sparse matrix in Coordinate format
+writeMatrix :: Show b => FilePath -> Matrix b -> IO ()
+writeMatrix file mat = 
+  case mat of (RMatrix d nz s dat) -> 
+                L.writeFile file (matrixByteString d nz R s dat)
+              (CMatrix d nz s dat) -> 
+                L.writeFile file (matrixByteString d nz C s dat)
+              (IntMatrix d nz s dat) -> 
+                L.writeFile file (matrixByteString d nz I s dat)
+              _ -> error "writeMatrix : PatternMatrix not implemented yet"
+     where
+       matrixByteString di nz t s d =
+         L.concat [headerStr Coordinate t s,
+                   nl,
+                   headerSzMatrix di nz,
+                   nl,
+                   showLines sf3 d]
+         where
+         sf3 (i,j,x) = unwords [show i, show j, show x]
+         headerSzMatrix (m,n) numz = B.pack $ unwords [show m, show n, show numz] 
+
+-- | Serialize a dense matrix in Array format
+writeArray :: Show a => FilePath -> Array a -> IO ()  
+writeArray file arr = 
+  case arr of (RArray d s dat) -> L.writeFile file (arrayByteString d R s dat)
+              (CArray d s dat) -> L.writeFile file (arrayByteString d C s dat)
+    where
+      arrayByteString di t s d =
+        L.concat [headerStr Array t s,
+            nl,
+            headerSzArray di,
+            nl,
+            showLines show d] where
+        headerSzArray (m,n) = B.pack $ unwords [show m, show n]
+  
+  
+
+
+
+
+
+
+-- | helpers
+
+
+nnz :: Matrix t -> Int
+nnz m = case m of (RMatrix _ nz _ _) -> nz
+                  (CMatrix _ nz _ _) -> nz
+                  (PatternMatrix _ nz _ _) -> nz
+                  (IntMatrix _ nz _ _) -> nz
+
+dim :: Matrix t -> (Int, Int)
+dim m = case m of (RMatrix d _ _ _) -> d
+                  (CMatrix d _ _ _) -> d
+                  (PatternMatrix d _ _ _) -> d
+                  (IntMatrix d _ _ _) -> d
+
+numDat :: Matrix t -> Int
+numDat m = case m of (RMatrix _ _ _ d) -> length d
+                     (CMatrix _ _ _ d) -> length d
+                     (PatternMatrix _ _ _ d) -> length d
+                     (IntMatrix _ _ _ d) -> length d
+
+
+dimArr :: Array t -> (Int, Int)
+dimArr a = case a of (RArray d _ _) -> d
+                     (CArray d _ _) -> d
+ 
+numDatArr :: Array a -> Int
+numDatArr a = case a of (RArray _ _ ll) -> length ll 
+                        (CArray _ _ ll) -> length ll            
+
+
+
+
+-- | String -> ByteString
+-- NB: do not abuse
+toBS :: String -> BS.ByteString
+toBS x = BS.pack $ (toEnum . C.ord) <$> x
+
+-- | String -> lazy ByteString
+toLBS :: String -> L.ByteString
+toLBS x = L.pack $ (toEnum . C.ord) <$> x
+
+
+
+
+-- t1 = toBS "%%MatrixMarket matrix coordinate real general\n5  5  8\n1     1   1.000e+00\n2     2   1.050e+01\n3     3   1.500e-02\n1     4   6.000e+00\n4     2   2.505e+02\n4     4  -2.800e+02\n4     5   3.332e+01\n5     5   1.200e+01\n"
+
+-- t2 = toBS "%%MatrixMarket matrix coordinate real general\n5  5  8\n1     1   1.000e+00\n"
diff --git a/test/LibSpec.hs b/test/LibSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/LibSpec.hs
@@ -0,0 +1,69 @@
+module LibSpec where
+
+import Control.Exception
+import System.Directory (removeFile)
+
+import Test.Hspec
+import Test.Hspec.QuickCheck
+
+import Data.Matrix.MatrixMarket
+
+
+
+main :: IO ()
+main = hspec spec
+
+spec :: Spec
+spec =
+  describe "Data.Matrix.MatrixMarket" $ do
+    -- prop "ourAdd is commutative" $ \x y ->
+    --   ourAdd x y `shouldBe` ourAdd y x
+    it "fidapm05 : read/write/read roundtrip" $ do 
+      roundTrip Coordinate "fidapm05.mtx" -- fidapm05_rhs1.mtx
+    it "fidapm05_rhs1 : read/write/read roundtrip" $ do 
+      roundTrip Array "fidapm05_rhs1.mtx"
+    -- it "memplus : read/write/read roundtrip" $ do 
+    --   roundTrip "memplus.mtx"
+    -- it "memplus_rhs1 : imports all array entries" $ do 
+    --   x <- readArray "data/memplus_rhs1.mtx"
+    --   consistentDimsArr x `shouldBe` True    
+
+
+-- | Helpers
+
+-- | Check if matrix dimensions (read from header vs counted from memory) coincide
+-- NB : only valid for General matrices (in MatrixMarket, symmetric entries are not written on file)
+consistentDims :: Matrix t -> Bool
+consistentDims m = nnz m == numDat m
+
+-- check if array dimensions (read from header vs counted from memory) coincide
+consistentDimsArr :: Array a -> Bool
+consistentDimsArr mm = d == numDatArr mm where
+  (m,n) = dimArr mm
+  d = m*n
+
+
+dataDir = "data"
+
+roundTrip :: Format -> FilePath -> IO ()
+roundTrip f fname0 = do
+  let
+    fname = dataDir ++ "/" ++ fname0
+    ftemp = fname ++ "_temp"
+  if f == Coordinate
+    then do   
+    m0 <- readMatrix fname   -- load original
+    writeMatrix ftemp m0     -- save as temp
+    m1 <- readMatrix ftemp   -- load temp
+    m0 `shouldBe` m1
+    else do
+    m0 <- readArray fname   -- load original
+    writeArray ftemp m0     -- save as temp
+    m1 <- readArray ftemp   -- load temp
+    m0 `shouldBe` m1
+  removeFile ftemp         -- remove temp 
+
+
+-- withTempFile :: IO FilePath -> (FilePath -> IO c) -> IO c
+-- withTempFile createf = bracket createf removeFile
+
diff --git a/test/Spec.hs b/test/Spec.hs
new file mode 100644
--- /dev/null
+++ b/test/Spec.hs
@@ -0,0 +1,1 @@
+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}