diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.markdown
@@ -0,0 +1,7 @@
+0.2.9.1
+-------
+
+* Uses classes from `vector-space` such as AdditiveGroup, VectorSpace and InnerSpace
+* QuickCheck tests for algebraic properties, such as matrix-vector products and soon more abstract ones e.g. positive semi-definite matrices
+* Getting rid of `error` in favor of MonadThrow exceptions for high-level operations
+such as matrix algorithms
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -38,8 +38,10 @@
 
     * QR (`eigsQR`)
 
-    * Rayleigh quotient iteration (`eigRayleigh`)
+    * QR-Arnoldi (`eigsArnoldi`) 
 
+
+
 * Utilities : Vector and matrix norms, matrix condition number, Givens rotation, Householder reflection
 
 * Predicates : Matrix orthogonality test (A^T A ~= I)
@@ -47,6 +49,10 @@
 
 
 ### Under development
+
+* Eigenvalue algorithms
+
+    * Rayleigh quotient iteration (`eigRayleigh`)
 
 * Matrix factorization algorithms
 
diff --git a/sparse-linear-algebra.cabal b/sparse-linear-algebra.cabal
--- a/sparse-linear-algebra.cabal
+++ b/sparse-linear-algebra.cabal
@@ -1,5 +1,5 @@
 name:                sparse-linear-algebra
-version:             0.2.9.2
+version:             0.2.9.3
 synopsis:            Numerical computation in native Haskell
 description:
   /Overview/
@@ -17,10 +17,11 @@
 license-file:        LICENSE
 author:              Marco Zocca
 maintainer:          zocca.marco gmail
-copyright:           2016 Marco Zocca
+copyright:           2016-2017 Marco Zocca
 category:            Numeric
 build-type:          Simple
 extra-source-files:  README.md
+                     CHANGELOG.markdown
 cabal-version:       >=1.10
 tested-with:         GHC == 8.0.1
 
diff --git a/src/Data/Sparse/Common.hs b/src/Data/Sparse/Common.hs
--- a/src/Data/Sparse/Common.hs
+++ b/src/Data/Sparse/Common.hs
@@ -21,7 +21,7 @@
          extractDiagDense,
          extractSubRow, extractSubCol,
          extractSubRow_RK, extractSubCol_RK,
-         fromCols, fromColsL, toCols) where
+         fromRowsL, fromRowsV, fromColsV, fromColsL, toRowsL, toColsL) where
 
 -- import Control.Exception
 -- import Control.Exception.Common
@@ -293,34 +293,41 @@
 
 
 
-
+-- | Pack a list of SpVectors as rows of an SpMatrix
+fromRowsL :: [SpVector a] -> SpMatrix a
+fromRowsL = fromRowsV . V.fromList
 
--- | Pack a list of SpVectors into an SpMatrix
+-- | Pack a list of SpVectors as columns an SpMatrix
 fromColsL :: [SpVector a] -> SpMatrix a
-fromColsL = fromCols . V.fromList
+fromColsL = fromColsV . V.fromList
 
--- | Unpack an SpMatrix into a list of SpVectors
-toCols :: SpMatrix a -> [SpVector a]
-toCols aa = map (extractCol aa) [0 .. n-1] where
+-- | Unpack the rows of an SpMatrix into a list of SpVectors
+toRowsL :: SpMatrix a -> [SpVector a]
+toRowsL aa = map (extractRow aa) [0 .. m-1] where
   (m,n) = dim aa
 
-
-
-
+-- | Unpack the columns of an SpMatrix into a list of SpVectors
+toColsL :: SpMatrix a -> [SpVector a]
+toColsL aa = map (extractCol aa) [0 .. n-1] where
+  (m,n) = dim aa
 
 
 
 
 -- | Pack a V.Vector of SpVectors as columns of an SpMatrix
-fromCols :: V.Vector (SpVector a) -> SpMatrix a
-fromCols qv = V.ifoldl' ins (zeroSM m n) qv where
+fromColsV :: V.Vector (SpVector a) -> SpMatrix a
+fromColsV qv = V.ifoldl' ins (zeroSM m n) qv where
   n = V.length qv
   m = dim $ V.head qv
   ins mm i c = insertCol mm c i
 
 
-
-
+-- | Pack a V.Vector of SpVectors as rows of an SpMatrix
+fromRowsV :: V.Vector (SpVector a) -> SpMatrix a
+fromRowsV qv = V.ifoldl' ins (zeroSM m n) qv where
+  n = V.length qv
+  m = svDim $ V.head qv
+  ins mm i c = insertRow mm c i
 
 
 
@@ -333,13 +340,13 @@
 showNz x | nearZero x = " _ "
          | otherwise = show x
 
--- toDenseRow :: Num a => SpMatrix a -> IM.Key -> [a]
+toDenseRow :: Num a => SpMatrix a -> IM.Key -> [a]
 toDenseRow sm irow =
-  fmap (\icol -> sm @@ (irow,icol)) [0..ncol-1] where (_, ncol) = dim sm
+  fmap (\icol -> sm @@ (irow,icol)) [0..ncol-1] where (_, ncol) = (nrows sm, ncols sm)
 
 
 
--- toDenseRowClip :: (Show a, Num a) => SpMatrix a -> IM.Key -> Int -> String
+toDenseRowClip :: (Show a, Num a, Epsilon a) => SpMatrix a -> IM.Key -> Int -> String
 toDenseRowClip sm irow ncomax
   | nco > ncomax = unwords (map showNz h) ++  " ... " ++ showNz t
   | otherwise = unwords $ showNz <$> dr
@@ -350,17 +357,22 @@
 
 
 -- printDenseSM :: (Show t, Num t) => SpMatrix t -> IO ()
-printDenseSM :: (ScIx c ~ (Int, Int), FDSize c ~ (Int, Int), SpContainer c a, Show a, Epsilon a) => c a -> IO ()
+-- printDenseSM :: (ScIx c ~ (Int, Int), FDSize c ~ (Int, Int), SpContainer c a, Show a, Epsilon a) => c a -> IO ()
 printDenseSM sm = do
   newline
   putStrLn $ sizeStr sm
   newline
+  printDenseSM0 sm
+
+printDenseSM0 sm = do
+  putStrLn $ sizeStr sm
+  newline
   printDenseSM' sm 5 5
   newline
   where    
     -- printDenseSM' :: (Show t, Num t) => SpMatrix t -> Int -> Int -> IO ()
     printDenseSM' sm' nromax ncomax = mapM_ putStrLn rr_' where
-      (nr, _) = dim sm'
+      (nr, _) = (nrows sm, ncols sm)
       rr_ = map (\i -> toDenseRowClip sm' i ncomax) [0..nr - 1]
       rr_' | nr > nromax = take (nromax - 2) rr_ ++ [" ... "] ++[last rr_]
            | otherwise = rr_
@@ -380,6 +392,10 @@
   newline
   putStrLn $ sizeStrSV sv
   newline
+  printDenseSV0 sv
+
+printDenseSV0 :: (Show t, Epsilon t) => SpVector t -> IO ()
+printDenseSV0 sv = do
   printDenseSV' sv 5
   newline where
     printDenseSV' v nco = putStrLn rr_' where
@@ -392,9 +408,11 @@
 
 instance (Show a, Num a, Epsilon a) => PrintDense (SpVector a) where
   prd = printDenseSV
+  prd0 = printDenseSV0
 
 instance (Show a, Num a, Epsilon a) => PrintDense (SpMatrix a) where
   prd = printDenseSM
+  prd0 = printDenseSM0
 
 
 
diff --git a/src/Data/Sparse/PPrint.hs b/src/Data/Sparse/PPrint.hs
--- a/src/Data/Sparse/PPrint.hs
+++ b/src/Data/Sparse/PPrint.hs
@@ -17,7 +17,10 @@
 
 
 class PrintDense a where
+  -- | Pretty-print with a descriptive header
   prd :: a -> IO ()
+  -- | Pretty-print with no header
+  prd0 :: a -> IO ()
 
 newline :: IO ()
 newline = putStrLn ""  
diff --git a/src/Numeric/LinearAlgebra/Class.hs b/src/Numeric/LinearAlgebra/Class.hs
--- a/src/Numeric/LinearAlgebra/Class.hs
+++ b/src/Numeric/LinearAlgebra/Class.hs
@@ -265,7 +265,7 @@
 -- ** Linear systems
   
 class LinearVectorSpace v => LinearSystem v where
-  -- | Solve a linear system
+  -- | Solve a linear system; uses GMRES internally as default method
   (<\>) :: (MonadIO m, MonadThrow m) =>
            MatrixType v   -- ^ System matrix
         -> v              -- ^ Right-hand side
diff --git a/src/Numeric/LinearAlgebra/Sparse.hs b/src/Numeric/LinearAlgebra/Sparse.hs
--- a/src/Numeric/LinearAlgebra/Sparse.hs
+++ b/src/Numeric/LinearAlgebra/Sparse.hs
@@ -57,25 +57,35 @@
          fromListSV, toListSV,
          -- ** From/to SpMatrix
          fromListSM, toListSM,
+         -- ** Packing/unpacking rows/columns of a sparse matrix
+         -- *** ", using lists as container
+         fromRowsL, toRowsL,
+         fromColsL, toColsL,
+         -- *** ", using Vector as container
+         fromRowsV, fromColsV,
          -- * Operators
+         (.*), (./), 
          -- ** Inner product
          (<.>),
-         -- ** Matrix-vector products
+         -- ** Matrix-vector product
          (#>), (<#),
-         -- ** Matrix-matrix products
+         -- ** Matrix-matrix product
          (##), (#^#), (##^),
-         -- *** Sparsifying matrix-matrix products
+         -- *** Sparsifying matrix-matrix product
          (#~#), (#~^#), (#~#^),
          -- ** Vector outer product
          (><),
          -- * Common operations
          dim, nnz, spy,
          -- ** Vector-related
-         (.*), (./), cvx,
+         cvx,
+         -- *** Norms and normalization
          norm, norm2, norm2', normalize, normalize2, normalize2',
          norm1, hilbertDistSq,
          -- ** Matrix-related
-         transpose, normFrobenius, 
+         transpose, normFrobenius,
+         -- * Pretty-printing
+         prd, prd0,
          -- * Iteration combinators
          untilConvergedG0, untilConvergedG, untilConvergedGM,
          modifyInspectGuarded, modifyInspectGuardedM, IterationConfig (..),
@@ -542,7 +552,7 @@
      -> SpVector a                 -- ^ r.h.s.
      -> Int                        -- ^ Max. # of iterations
      -> m (SpMatrix a, SpMatrix a) -- ^ Q, H
-arnoldi aa b kn | n == nb = return (fromCols qvfin, fromListSM (nmax + 1, nmax) hhfin)
+arnoldi aa b kn | n == nb = return (fromColsV qvfin, fromListSM (nmax + 1, nmax) hhfin)
                 | otherwise = throwM (MatVecSizeMismatchException "arnoldi" (m,n) nb)
   where
   (qvfin, hhfin, nmax, _) = execState (modifyUntil tf arnoldiStep) arnInit 
@@ -890,7 +900,7 @@
 
 
 -- * Moore-Penrose pseudoinverse
--- | Least-squares approximation of a rectangular system of equaitons. Uses (<\>) for the linear solve
+-- | Least-squares approximation of a rectangular system of equaitons. Uses `(<\>)` for the linear solve
 pinv :: (MatrixType v ~ SpMatrix a, LinearSystem v, Epsilon a,
          MonadThrow m, MonadIO m) =>
      SpMatrix a -> v -> m v
@@ -900,7 +910,7 @@
 
 
 
--- | Interface method to individual linear solvers
+-- | Interface method to individual linear solvers, do not use directly
 linSolve0 method aa b x0
   | m /= nb = throwM (MatVecSizeMismatchException "linSolve0" dm nb)
   | otherwise = solve aa b where
@@ -920,7 +930,7 @@
       xf <- untilConvergedG fname config (const True) stepf initf
       return $ fproj xf
       where
-        config = IterConf nitermax True fproj prd
+        config = IterConf nitermax True fproj prd0
   
 
 -- * Linear solver interface