saveMatrix

2 files changed, 24 insertions, 6 deletions

diff --git a/lib/Data/Packed/Internal/Matrix.hs b/lib/Data/Packed/Internal/Matrix.hs
index 01d2ccf..68547bd 100644
--- a/lib/Data/Packed/Internal/Matrix.hs
+++ b/lib/Data/Packed/Internal/Matrix.hs
@@ -23,6 +23,7 @@ import Data.Packed.Internal.Vector
 import Foreign hiding (xor)
 import Complex
 import Foreign.C.Types
+import Foreign.C.String
 
 -----------------------------------------------------------------
 
@@ -350,6 +351,19 @@ fromComplex :: Vector (Complex Double) -> (Vector Double, Vector Double)
 fromComplex z = (r,i) where
     [r,i] = toColumns $ reshape 2 $ asReal z
 
--- | loads a matrix from an ASCII file (the number of rows and columns must be known in advance).
-fromFile :: FilePath -> (Int,Int) -> IO (Matrix Double)
-fromFile filename (r,c) = reshape c `fmap` fscanfVector filename (r*c)
+--------------------------------------------------------------------------
+
+-- | Saves a matrix as 2D ASCII table.
+saveMatrix :: FilePath
+           -> String     -- ^ format (%f, %g, %e)
+           -> Matrix Double
+           -> IO ()
+saveMatrix filename fmt m = do
+    charname <- newCString filename
+    charfmt <- newCString fmt
+    let o = if orderOf m == RowMajor then 1 else 0
+    app1 (matrix_fprintf charname charfmt o) mat m "matrix_fprintf"
+    free charname
+    free charfmt
+
+foreign import ccall "matrix_fprintf" matrix_fprintf :: Ptr CChar -> Ptr CChar -> CInt -> TM
diff --git a/lib/Data/Packed/Matrix.hs b/lib/Data/Packed/Matrix.hs
index 32eb991..ad0776e 100644
--- a/lib/Data/Packed/Matrix.hs
+++ b/lib/Data/Packed/Matrix.hs
@@ -30,7 +30,7 @@ module Data.Packed.Matrix (
     ident, diag, diagRect, takeDiag,
     liftMatrix, liftMatrix2,
     format,
-    loadMatrix, fromFile, fileDimensions,
+    loadMatrix, saveMatrix, fromFile, fileDimensions,
     readMatrix, fromArray2D
 ) where
 
@@ -247,11 +247,15 @@ fileDimensions fname = do
         then return (tot `div` c, c)
         else return (0,0)
 
-{- | loads a matrix from a formatted ASCII file.
--}
+-- | Loads a matrix from an ASCII file formatted as a 2D table.
 loadMatrix :: FilePath -> IO (Matrix Double)
 loadMatrix file = fromFile file =<< fileDimensions file
 
+-- | Loads a matrix from an ASCII file (the number of rows and columns must be known in advance).
+fromFile :: FilePath -> (Int,Int) -> IO (Matrix Double)
+fromFile filename (r,c) = reshape c `fmap` fscanfVector filename (r*c)
+
+
 -- | rearranges the rows of a matrix according to the order given in a list of integers. 
 extractRows :: Element t => [Int] -> Matrix t -> Matrix t
 extractRows l m = fromRows $ extract (toRows $ m) l