2 files changed, 13 insertions, 1 deletions

diff --git a/hmatrix.cabal b/hmatrix.cabal
index 514d562..800e7b0 100644
--- a/hmatrix.cabal
+++ b/hmatrix.cabal
@@ -88,7 +88,8 @@ library
                         storable-complex,
                         process, random,
                         vector >= 0.8,
-                        binary
+                        binary,
+                        deepseq
 
     Extensions:         ForeignFunctionInterface,
                         CPP
diff --git a/lib/Data/Packed/Internal/Matrix.hs b/lib/Data/Packed/Internal/Matrix.hs
index b8ed18d..367c189 100644
--- a/lib/Data/Packed/Internal/Matrix.hs
+++ b/lib/Data/Packed/Internal/Matrix.hs
@@ -47,6 +47,7 @@ import Data.Complex(Complex)
 import Foreign.C.Types
 import Foreign.C.String(newCString)
 import System.IO.Unsafe(unsafePerformIO)
+import Control.DeepSeq
 
 -----------------------------------------------------------------
 
@@ -459,3 +460,13 @@ size m = (rows m, cols m)
 
 shSize m = "(" ++ show (rows m) ++"><"++ show (cols m)++")"
 
+----------------------------------------------------------------------
+
+instance (Storable t, NFData t) => NFData (Matrix t)
+  where
+    rnf m | d > 0     = rnf (v @> 0)
+          | otherwise = ()
+      where
+        d = dim v
+        v = xdat m
+