Changes between Version 37 and Version 38 of DataParallel/Replicate

Timestamp:

08/21/11 20:28:59 (22 months ago)

Author:

chak

Comment:

--

DataParallel/Replicate

@@ -163 +163 @@
 Arrays with virtual segments can not always be combined without duplicating the data corresponding to repeated segments (after all, a disjoint segment may be inserted into a sequence of repeated segments).  For simplicity, we may want to expand all repeated segments and remove all not used physical segments in `combinePA`.  (It seems that this should not lead to unexpected blow-ups as the repeated data now is part of a functions result and should be accounted for in its complexity estimate.)
 
+Some examples:
+{{{
+desire:dph-common-vseg benl$ ghc --interactive examples/Test.hs -package dph-par -package dph-prim-par -Iinclude
+
+
+-- pprv : pretty print virtual array
+*Test> pprv arrN3
+[[0],[1,2,3],[5,6,7,8,9]]
+
+
+-- pprp : pretty print physical array
+*Test> pprp arrN3
+PArray  3
+   PNested
+       vsegids:    [0,1,2]
+       pseglens:   [1,3,5]
+       psegstarts: [0,1,4]
+       psegsrcs:   [0,0,0]
+       PInt [0,1,2,3,5,6,7,8,9]
+
+
+-- With segmented replicate we only replicate the vsegs fields
+--  The functions ending PA' take lists for some arguments, and are just for experimentation.
+--  Functions ending in plain PA take real arrays.
+
+*Test> pprv $ replicatesPA' [2, 4, 3] arrN3
+[[0],[0],[1,2,3],[1,2,3],[1,2,3],[1,2,3],[5,6,7,8,9],[5,6,7,8,9],[5,6,7,8,9]]
+
+*Test> pprp $ replicatesPA' [2, 4, 3] arrN3
+PArray  9
+   PNested
+       vsegids:    [0,0,1,1,1,1,2,2,2]
+       pseglens:   [1,3,5]
+       psegstarts: [0,1,4]
+       psegsrcs:   [0,0,0]
+       PInt [0,1,2,3,5,6,7,8,9]
+
+
+-- To pack an array, we pack the vsegs then drop out the psegs that 
+-- aren't referenced by any vseg.
+
+*Test> pprv $ packByTagPA' (replicatesPA' [2, 4, 3] arrN3) [1, 0, 0, 0, 0, 0, 1, 0, 1] 1
+[[0],[5,6,7,8,9],[5,6,7,8,9]]
+
+*Test> pprp $ packByTagPA' (replicatesPA' [2, 4, 3] arrN3) [1, 0, 0, 0, 0, 0, 1, 0, 1] 1
+PArray  0
+   PNested
+       vsegids:    [0,1,1]
+       pseglens:   [1,5]
+       psegstarts: [0,4]
+       psegsrcs:   [0,0]
+       PInt [0,1,2,3,5,6,7,8,9]
+
+
+-- Applying concatPA merges the two outermost layers.
+
+*Test> pprv $ concatPA $ packByTagPA' (replicatesPA' [2, 4, 3] arrN3) [1, 0, 0, 0, 0, 0, 1, 0, 1] 1
+[0,5,6,7,8,9,5,6,7,8,9]
+
+*Test> pprp $ concatPA $ packByTagPA' (replicatesPA' [2, 4, 3] arrN3) [1, 0, 0, 0, 0, 0, 1, 0, 1] 1
+PArray  11
+   PInt [0,5,6,7,8,9,5,6,7,8,9]
+}}}
+
 === Reduction ===
 
@@ -176 +240 @@
 
 As we saw in the previous subsection, some physical segments may not appear as virtual segments at all (if a replicated array shrunk by applying a pack operation).  Hence, we need to be careful that `sumP^` only reduces those physical segments of the array that are used by one or more virtual segments.
+
+=== Append ===
+
+{{{
+*Test> :type arrN3
+arrN3 :: PArray (PArray Int)
+
+*Test> pprv arrN3
+[[0],[1,2,3],[5,6,7,8,9]]
+
+*Test> pprp arrN3
+PArray  3
+   PNested
+       vsegids:    [0,1,2]
+       pseglens:   [1,3,5]
+       psegstarts: [0,1,4]
+       psegsrcs:   [0,0,0]
+       PInt [0,1,2,3,5,6,7,8,9]
+
+
+*Test> pprv arrN4
+[[7,8,9,10,11,12,13],[0],[1,2,3],[0]]
+
+*Test> pprp arrN4
+PArray  4
+   PNested
+       vsegids:    [0,1,2,3]
+       pseglens:   [7,1,3,1]
+       psegstarts: [0,7,8,11]
+       psegsrcs:   [0,0,0,0]
+       PInt [7,8,9,10,11,12,13,0,1,2,3,0]
+
+
+-- Append is also an index space transform. When we append two arrays
+-- we append the segmentation information, but just put both flat arrays
+-- into the result, without copying their data. Note how the result
+-- contains both PInt arrays from the source.
+
+*Test> pprv $ arrN3 `appPA` arrN4
+[[0],[1,2,3],[5,6,7,8,9],[7,8,9,10,11,12,13],[0],[1,2,3],[0]]
+
+
+*Test> pprp $ arrN3 `appPA` arrN4
+PArray  7
+   PNested
+       vsegids:    [0,1,2,3,4,5,6]
+       pseglens:   [1,3,5,7,1,3,1]
+       psegstarts: [0,1,4,0,7,8,11]
+       psegsrcs:   [0,0,0,1,1,1,1]
+       PInt [0,1,2,3,5,6,7,8,9]
+       PInt [7,8,9,10,11,12,13,0,1,2,3,0]
+}}}
 
 === Splitting and joining (for distribution across threads) ===