diff --git a/hTensor.cabal b/hTensor.cabal
--- a/hTensor.cabal
+++ b/hTensor.cabal
@@ -1,5 +1,5 @@
 Name:               hTensor
-Version:            0.7.0.1
+Version:            0.8.0
 License:            GPL
 License-file:       LICENSE
 Author:             Alberto Ruiz
@@ -26,7 +26,7 @@
  A tutorial can be found in the website of the project.
 
 Category:           Math
-tested-with:        GHC ==6.12.1
+tested-with:        GHC ==7.4
 
 cabal-version:      >=1.6
 build-type:         Simple
@@ -42,7 +42,7 @@
     else
       build-depends:    base < 3
 
-    Build-Depends:      hmatrix >= 0.10, containers, random
+    Build-Depends:      hmatrix >= 0.13, containers, random
 
     hs-source-dirs:     lib
     Exposed-modules:    Numeric.LinearAlgebra.Array.Util
@@ -62,4 +62,8 @@
     ghc-options:        -Wall
                         -fno-warn-missing-signatures
                         -fno-warn-orphans
+
+source-repository head
+    type:     git
+    location: https://github.com/AlbertoRuiz/hTensor
 
diff --git a/lib/Numeric/LinearAlgebra/Array.hs b/lib/Numeric/LinearAlgebra/Array.hs
--- a/lib/Numeric/LinearAlgebra/Array.hs
+++ b/lib/Numeric/LinearAlgebra/Array.hs
@@ -42,7 +42,7 @@
 (.*) :: (Coord a, Compat i) => NArray i a -> NArray i a -> NArray i a
 (.*) = zipArray (*)
 
-instance (Coord t, Compat i) => Eq (NArray i t) where
+instance (Eq t, Coord t, Compat i) => Eq (NArray i t) where
     t1 == t2 = sameStructure t1 t2 && coords t1 == coords (reorder (namesR t1) t2)
 
 instance (Show (NArray i t), Coord t, Compat i) => Num (NArray i t) where
diff --git a/lib/Numeric/LinearAlgebra/Array/Decomposition.hs b/lib/Numeric/LinearAlgebra/Array/Decomposition.hs
--- a/lib/Numeric/LinearAlgebra/Array/Decomposition.hs
+++ b/lib/Numeric/LinearAlgebra/Array/Decomposition.hs
@@ -25,7 +25,7 @@
 import Numeric.LinearAlgebra.Array.Internal(seqIdx,namesR,sizesR,renameRaw)
 import Numeric.LinearAlgebra.Array.Util
 import Numeric.LinearAlgebra.Array.Solve
-import Numeric.LinearAlgebra hiding ((.*), scalar)
+import Numeric.LinearAlgebra hiding (scalar)
 import Data.List
 import System.Random
 --import Control.Parallel.Strategies
diff --git a/lib/Numeric/LinearAlgebra/Array/Internal.hs b/lib/Numeric/LinearAlgebra/Array/Internal.hs
--- a/lib/Numeric/LinearAlgebra/Array/Internal.hs
+++ b/lib/Numeric/LinearAlgebra/Array/Internal.hs
@@ -76,7 +76,7 @@
 debug m f x = trace (m ++ show (f x)) x
 
 -- | Types that can be elements of the multidimensional arrays.
-class (Num (Vector t), Field t, Normed Vector t) => Coord t
+class (Num (Vector t), Field t, Normed Vector t, Show t) => Coord t
 instance Coord Double
 instance Coord (Complex Double)
 
diff --git a/lib/Numeric/LinearAlgebra/Array/Solve.hs b/lib/Numeric/LinearAlgebra/Array/Solve.hs
--- a/lib/Numeric/LinearAlgebra/Array/Solve.hs
+++ b/lib/Numeric/LinearAlgebra/Array/Solve.hs
@@ -31,7 +31,7 @@
 import Numeric.LinearAlgebra.Array.Util
 import Numeric.LinearAlgebra.Exterior
 import Numeric.LinearAlgebra.Array.Internal(mkNArray, selDims, debug, namesR)
-import Numeric.LinearAlgebra hiding ((.*), scalar)
+import Numeric.LinearAlgebra hiding (scalar)
 import Data.List
 import System.Random
 
@@ -172,7 +172,7 @@
 
 -- | Solution of a multilinear system a x y z ... = b based on alternating least squares.
 mlSolve
-  :: (Compat i, Coord t, Num (NArray i t))
+  :: (Compat i, Coord t, Num (NArray i t), Show (NArray i t))
      => ALSParam i t     -- ^ optimization parameters
      -> [NArray i t]  -- ^ coefficients (a), given as a list of factors.
      -> [NArray i t]  -- ^ initial solution [x,y,z...]
@@ -192,7 +192,7 @@
 
 -- | Solution of the homogeneous multilinear system a x y z ... = 0 based on alternating least squares.
 mlSolveH
-  :: (Compat i, Coord t, Num (NArray i t))
+  :: (Compat i, Coord t, Num (NArray i t), Show (NArray i t))
      => ALSParam  i t    -- ^ optimization parameters
      -> [NArray i t]  -- ^ coefficients (a), given as a list of factors.
      -> [NArray i t]  -- ^ initial solution [x,y,z...]
@@ -232,7 +232,7 @@
 {- | Given two arrays a (source) and  b (target), we try to compute linear transformations x,y,z,... for each dimension, such that product [a,x,y,z,...] == b.
 (We can use 'eqnorm' for 'post' processing, or 'id'.)
 -}
-solveFactors :: (Coord t, Random t, Compat i, Num (NArray i t))
+solveFactors :: (Coord t, Random t, Compat i, Num (NArray i t), Show (NArray i t))
              => Int          -- ^ seed for random initialization
              -> ALSParam i t     -- ^ optimization parameters
              -> [NArray i t] -- ^ source (also factorized)
@@ -245,7 +245,7 @@
 initFactorsSeq rs a pairs b | ok = as
                             | otherwise = error "solveFactors index pairs"
   where
-    (ia,ib) = unzip (map (\[x,y]->([x],[y])) (words pairs))
+    (ia,ib) = unzip (map sep (words pairs))
     ic = intersect (namesR a) (namesR b)
     ok = sort (namesR b\\ic) == sort ib && sort (namesR a\\ic) == sort ia
     db = selDims (dims b) ib
@@ -264,7 +264,7 @@
 -- [\"pi\",\"qj\", \"rk\", etc.], we try to compute linear transformations
 -- x!\"pi\", y!\"pi\", z!\"rk\", etc. such that product [a,x,y,z,...] == 0.
 solveFactorsH
-  :: (Coord t, Random t, Compat i, Num (NArray i t))
+  :: (Coord t, Random t, Compat i, Num (NArray i t), Show (NArray i t))
      => Int -- ^ seed for random initialization
      -> ALSParam  i t    -- ^ optimization parameters
      -> [NArray i t] -- ^ coefficient array (a), (also factorized)
@@ -274,7 +274,7 @@
     mlSolveH params a (initFactorsHRandom seed (smartProduct a) pairs)
 
 initFactorsHSeq rs a pairs = as where
-    (ir,it) = unzip (map (\[x,y]->([x],[y])) (words pairs))
+    (ir,it) = unzip (map sep (words pairs))
     nr = map (flip size a) ir
     nt = map (flip size a) it
     ts = takes (zipWith (*) nr nt) rs
@@ -282,6 +282,9 @@
     f c i1 i2 d1 d2 = (mkNArray (map opos [d1,d2]) (fromList c)) `renameO` [i1,i2]
 
 initFactorsHRandom seed a pairs = initFactorsHSeq (randomRs (-1,1) (mkStdGen seed)) a pairs
+
+sep [a,b] = ([a],[b])
+sep _ = error "impossible pattern in hTensor initFactors"
 
 ----------------------------------
 
diff --git a/lib/Numeric/LinearAlgebra/Array/Util.hs b/lib/Numeric/LinearAlgebra/Array/Util.hs
--- a/lib/Numeric/LinearAlgebra/Array/Util.hs
+++ b/lib/Numeric/LinearAlgebra/Array/Util.hs
@@ -68,8 +68,10 @@
 -- For instance, @t >\@> \"pi qj\"@ changes index \"p\" to \"i\" and \"q\" to \"j\".
 (!>) :: (Compat i, Coord t) => NArray i t -> [Char] -> NArray i t
 infixl 9 !>
-t !> s = renameExplicit (map (\[a,b]->([a],[b])) (words s)) t
-
+t !> s = renameExplicit (map f (words s)) t
+  where
+    f [a,b] = ([a],[b])
+    f _ = error "impossible pattern in hTensor (!>)"
 
 -- | Rename indices in alphabetical order. Equal indices of compatible type are contracted out.
 renameO :: (Coord t, Compat i)