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|
{-# LANGUAGE ForeignFunctionInterface #-}
module Math.LinProg.LPSolve.FFI (
ResultCode(..)
,ConstraintType(..)
,LPRec
,setConstrType
,makeLP
,freeLP
,setMat
,setRHS
,solve
,getSol
) where
import Foreign
import Foreign.C
import Control.Applicative ((<$>))
import qualified Data.Map as M
type LPRec = Ptr ()
data ResultCode =
NoMemory
|Optimal
|SubOptimal
|Infeasible
|Unbounded
|Degenerate
|NumFailure
|UserAbort
|Timeout
|PreSolved
|ProcFail
|ProcBreak
|FeasFound
|NoFeasFound
deriving (Show, Eq, Ord)
data ConstraintType =
Fr
|LE
|GE
|EQ
deriving (Show, Eq, Ord, Enum)
foreign import ccall "make_lp" c_make_lp :: CInt -> CInt -> IO LPRec
foreign import ccall "free_lp" c_free_lp :: Ptr LPRec -> IO ()
foreign import ccall "set_mat" c_set_mat :: LPRec -> CInt -> CInt -> CDouble -> IO CChar
foreign import ccall "set_rh" c_set_rh :: LPRec -> CInt -> CDouble -> IO CChar
foreign import ccall "solve" c_solve :: LPRec -> IO CInt
foreign import ccall "get_variables" c_get_variables :: LPRec -> Ptr CDouble -> IO CChar
foreign import ccall "set_constr_type" c_set_constr_type :: LPRec -> CInt -> CInt -> IO CChar
setConstrType :: LPRec -> Int -> ConstraintType -> IO Word8
setConstrType lp i t = fromIntegral <$> c_set_constr_type lp (fromIntegral i) (fromIntegral $ fromEnum t)
makeLP :: Int -> Int -> IO (Maybe LPRec)
makeLP n m = do
m' <- c_make_lp (fromIntegral n) (fromIntegral m)
return $ if m' == nullPtr then
Nothing
else
Just m'
freeLP :: LPRec -> IO ()
freeLP m = with m $ \m' -> c_free_lp m'
setMat :: LPRec -> Int -> Int -> Double -> IO Word8
setMat a b c d = fromIntegral <$> c_set_mat a (fromIntegral b) (fromIntegral c) (realToFrac d)
setRHS :: LPRec -> Int -> Double -> IO Word8
setRHS a b c = fromIntegral <$> c_set_rh a (fromIntegral b) (realToFrac c)
solve :: LPRec -> IO ResultCode
solve lp = (lut M.!) . fromIntegral <$> c_solve lp
where
lut = M.fromList [
(-2, NoMemory)
,(0 :: Int, Optimal)
,(1, SubOptimal)
,(2, Infeasible)
,(3, Unbounded)
,(4, Degenerate)
,(5, NumFailure)
,(6, UserAbort)
,(7, Timeout)
,(9, PreSolved)
,(10, ProcFail)
,(11, ProcBreak)
,(12, FeasFound)
,(13, NoFeasFound)
]
getSol :: Int -> LPRec -> IO (Word8, [Double])
getSol n lp = allocaArray (1+n) $ \arr -> do
res <- c_get_variables lp arr
vals <- peekArray (1+n) arr
let vs = map realToFrac vals
return (fromIntegral res, vs)
|
