Merge pull request #2097 from STEllAR-GROUP/reduce_by_key

Reduce by key, extends #1141
STEllAR-GROUP · Apr 22, 2016 · 82bb1c2 · 82bb1c2
2 parents a86ced1 + c14c97b
commit 82bb1c2
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diff --git a/docs/CMakeLists.txt b/docs/CMakeLists.txt
@@ -84,6 +84,7 @@ set(doxygen_dependencies
     "${PROJECT_SOURCE_DIR}/hpx/parallel/algorithms/mismatch.hpp"
     "${PROJECT_SOURCE_DIR}/hpx/parallel/algorithms/move.hpp"
     "${PROJECT_SOURCE_DIR}/hpx/parallel/algorithms/reduce.hpp"
+    "${PROJECT_SOURCE_DIR}/hpx/parallel/algorithms/reduce_by_key.hpp"
     "${PROJECT_SOURCE_DIR}/hpx/parallel/algorithms/remove_copy.hpp"
     "${PROJECT_SOURCE_DIR}/hpx/parallel/algorithms/replace.hpp"
     "${PROJECT_SOURCE_DIR}/hpx/parallel/algorithms/reverse.hpp"

diff --git a/docs/hpx.idx b/docs/hpx.idx
@@ -228,6 +228,9 @@ parallel::move                        "move" "hpx\.parallel\.v1\.move$"
 # hpx/parallel/algorithms/reduce.hpp
 parallel::reduce                      "reduce" "hpx\.parallel\.v1\.reduce.*"
 
+# hpx/parallel/algorithms/reduce_by_key.hpp
+parallel::reduce_by_key               "reduce_by_key" "hpx\.parallel\.v1\.reduce_by_key.*"
+
 # hpx/parallel/algorithms/for_loop_reduction.hpp
 parallel::reduction                   "reduction" "hpx\.parallel\.v2\.reduction"
 parallel::reduction_plus              "reduction_plus" "hpx\.parallel\.v2\.reduction_plus"

diff --git a/docs/manual/parallel_algorithms.qbk b/docs/manual/parallel_algorithms.qbk
@@ -314,6 +314,11 @@ __hpx__ provides implementations of the following parallel algorithms:
     [[ [algoref reduce] ]
      [Sums up a range of elements.]
      [`<hpx/include/parallel_reduce.hpp>`]]
+    [[ [algoref reduce_by_key] ]
+     [Performs an inclusive scan on consecutive elements with matching keys, with a reduction
+      to output only the final sum for each key. The key sequence {1,1,1,2,3,3,3,3,1} and value
+      sequence {2,3,4,5,6,7,8,9,10} would be reduced to keys={1,2,3,1}, values={9,5,30,10}]
+     [`<hpx/include/parallel_reduce.hpp>`]]
     [[ [algoref transform_reduce] ]
      [Sums up a range of elements after applying a function.]
      [`<hpx/include/parallel_transform_reduce.hpp>`]]

diff --git a/hpx/include/parallel_reduce.hpp b/hpx/include/parallel_reduce.hpp
@@ -8,6 +8,7 @@
 #define HPX_PARALLEL_REDUCE_JUN_28_2014_0827AM
 
 #include <hpx/parallel/algorithms/reduce.hpp>
+#include <hpx/parallel/algorithms/reduce_by_key.hpp>
 
 #endif