add Layout module

haskell-igraph.cabal

@@ -27,12 +27,14 @@ library
     IGraph.Internal.Structure
     IGraph.Internal.Clique
     IGraph.Internal.Community
+    IGraph.Internal.Layout
     IGraph
     IGraph.Mutable
     IGraph.Clique
     IGraph.Structure
     IGraph.Community
     IGraph.Read
+    IGraph.Layout
   -- other-modules:       
   -- other-extensions:    
   build-depends:
@@ -42,6 +44,7 @@ library
     , primitive
     , unordered-containers
     , hashable
+    , split
 
   extra-libraries:     igraph
   hs-source-dirs:      src

src/IGraph/Internal/Data.chs

@@ -7,6 +7,8 @@ import Foreign
 import Foreign.C.Types
 import Foreign.C.String
 import System.IO.Unsafe (unsafePerformIO)
+import Data.List (transpose)
+import Data.List.Split (chunksOf)
 
 #include "cbits/haskelligraph.c"
 
@@ -111,6 +113,32 @@ listToStrVector xs = do
 
 {#fun igraph_matrix_fill as ^ { `MatrixPtr', `Double' } -> `()' #}
 
-{#fun pure igraph_matrix_e as ^ { `MatrixPtr', `Int', `Int' } -> `Double' #}
+{#fun igraph_matrix_e as ^ { `MatrixPtr', `Int', `Int' } -> `Double' #}
 
-{#fun pure igraph_matrix_set as ^ { `MatrixPtr', `Int', `Int', `Double' } -> `()' #}
+{#fun igraph_matrix_set as ^ { `MatrixPtr', `Int', `Int', `Double' } -> `()' #}
+
+{#fun igraph_matrix_copy_to as ^ { `MatrixPtr', id `Ptr CDouble' } -> `()' #}
+
+{#fun igraph_matrix_nrow as ^ { `MatrixPtr' } -> `Int' #}
+
+{#fun igraph_matrix_ncol as ^ { `MatrixPtr' } -> `Int' #}
+
+listsToMatrixPtr :: [[Double]] -> IO MatrixPtr
+listsToMatrixPtr xs = do
+    mptr <- igraphMatrixNew r c
+    forM_ (zip [0..] xs) $ \(i, row) ->
+        forM_ (zip [0..] row) $ \(j,v) ->
+            igraphMatrixSet mptr i j v
+    return mptr
+  where
+    r = length xs
+    c = maximum $ map length xs
+
+matrixPtrToLists :: MatrixPtr -> IO [[Double]]
+matrixPtrToLists mptr = do
+    r <- igraphMatrixNrow mptr
+    c <- igraphMatrixNcol mptr
+    xs <- allocaArray (r*c) $ \ptr -> do
+        igraphMatrixCopyTo mptr ptr
+        peekArray (r*c) ptr
+    return $ transpose $ chunksOf r $ map realToFrac xs

src/IGraph/Internal/Layout.chs

+{-# LANGUAGE ForeignFunctionInterface #-}
+module IGraph.Internal.Layout where
+
+import Foreign
+import Foreign.C.Types
+
+{#import IGraph.Internal.Graph #}
+{#import IGraph.Internal.Data #}
+
+#include "igraph/igraph.h"
+
+{#fun igraph_layout_kamada_kawai as ^ { `IGraphPtr'
+, `MatrixPtr'
+, `Int'
+, `Double'
+, `Double'
+, `Double'
+, `Double'
+, `Bool'
+, id `Ptr VectorPtr'
+, id `Ptr VectorPtr'
+, id `Ptr VectorPtr'
+, id `Ptr VectorPtr'
+} -> `Int' #}

src/IGraph/Layout.hs

+module IGraph.Layout
+    ( kamadaKawai
+    ) where
+
+import Foreign (nullPtr)
+import Control.Applicative ((<$>))
+import System.IO.Unsafe (unsafePerformIO)
+
+import IGraph
+import IGraph.Internal.Clique
+import IGraph.Internal.Layout
+import IGraph.Internal.Data
+
+data LayoutOpt = LayoutOpt
+    { _seed :: Maybe [(Double, Double)]
+    , _nIter :: Int
+    } deriving (Show)
+
+kamadaKawai :: Graph d => LGraph d v e -> Double -> Double -> Double -> Double -> LayoutOpt -> [(Double, Double)]
+kamadaKawai gr sigma initemp coolexp kkconst opt = unsafePerformIO $ do
+    mptr <- mat
+    igraphLayoutKamadaKawai (_graph gr) mptr (_nIter opt) sigma initemp coolexp kkconst useSeed nullPtr nullPtr nullPtr nullPtr
+    [x, y] <- matrixPtrToLists mptr
+    return $ zip x y
+  where
+    (useSeed, mat) = case _seed opt of
+        Just xs -> if length xs /= nNodes gr
+                      then error "Seed error: incorrect size"
+                      else (True, f xs)
+        _ -> (False, igraphMatrixNew 0 0)
+    f xs = let (x,y) = unzip xs
+           in listsToMatrixPtr [x,y]