incremental changes to filterbank.hs

examples/filterbank.hs

@@ -4,38 +4,70 @@ import Control.Monad.Par
 import Control.Monad.Par.OpenList
 import Control.DeepSeq
 import Data.Array.Unboxed
+import Debug.Trace
 
 
-bufsize = 256
+-- bufsize = 256
+bufsize = 8
 
 --type Stream a = OpenList (UArray Int a)
 type Stream a = IList (UArray Int a)
 
 stage :: Stream Float -> Stream Float -> Par ()
 stage instrm outstrm = 
---  undefined
   do 
      let input = hd instrm
-         output = amap (+1) input
+         output = amap (+100) input
+     print_$ "Executing filter stage, output: "++ show output
      cell <- newCell output
      -- Append to the end of the output stream:
      put (tl outstrm) cell
      nxt <- get (tl instrm)
+     print_ "Put result to output stream..."
      stage nxt cell
 
-source :: Stream Float -> Par ()
-source outstrm = loop 0 outstrm
+-- If this loops forever a serial execution of the program can fail.
+source :: Int -> Stream Float -> Par ()
+source max outstrm = loop 0 outstrm
  where 
+  loop n strm | n > max = do put (tl strm) Null
+                             return ()
   loop n strm = 
-    do let arr = array (0,n-1) [(i,fromIntegral (n+i)) | i <- [0..bufsize]]
+    do let arr = array (0,bufsize-1) [(i,fromIntegral (n+i)) | i <- [0..bufsize-1]]
        cell <- newCell arr
        put (tl strm) cell 
        loop (n+bufsize) cell
 
+-- print_ msg = trace msg (return ())
 
-test = 
-  do cell <- newCell (array (0,0) [])
-     source cell
+sample cell1 =
+  do 
+     print_$ "1st: "++show (hd cell1)
+     cell2 <- get (tl cell1)
+     print_$ "\n  2nd: "++show (hd cell2)
+     cell3 <- get (tl cell2)
+     print_$ "\n  3rd: "++show (hd cell3)
+
+
+
+test = runPar$ 
+  do strm1 <- newCell (array (0,0) [])
+--     fork$ source 10000 strm1
+     fork$ source 100 strm1
+--     fork$ source 5 strm1
+     sample strm1
+
+     print_$ "\n Next, applying filter... "
+     strm2 <- newCell (array (0,0) [])
+     stage strm1 strm2
+
+     print_$ "\n Resulting stream: "
+     sample strm2
+
+     print_$ "\n Done"
+
+
+print_ msg = trace msg $ return ()
 
 instance NFData (UArray a b) where