std_algos: fix wrong corner case for is_partitioned (kokkos#6257)

* std_algos: fix wrong corner case for is_partitioned * avoid turning format off
nliber · Jul 5, 2023 · 07a0f0c · 07a0f0c
1 parent 6a8488d
commit 07a0f0c
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Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/algorithms/src/std_algorithms/impl/Kokkos_IsPartitioned.hpp b/algorithms/src/std_algorithms/impl/Kokkos_IsPartitioned.hpp
@@ -109,8 +109,16 @@ bool is_partitioned_impl(const std::string& label, const ExecutionSpace& ex,
 
   if (red_result.max_loc_true != red_id_max &&
       red_result.min_loc_false != red_id_min) {
+    // this occurs when the reduction yields nontrivial values
     return red_result.max_loc_true < red_result.min_loc_false;
+  } else if (red_result.max_loc_true == red_id_max &&
+             red_result.min_loc_false == 0) {
+    // this occurs when all values do NOT satisfy
+    // the predicate, and this corner case should also be true
+    return true;
   } else if (first + red_result.max_loc_true == --last) {
+    // this occurs when all values DO satisfy the predicate,
+    // this corner case should also be true
     return true;
   } else {
     return false;

diff --git a/algorithms/unit_tests/TestStdAlgorithmsPartitioningOps.cpp b/algorithms/unit_tests/TestStdAlgorithmsPartitioningOps.cpp
@@ -127,7 +127,7 @@ struct std_algorithms_partitioning_test : public std_algorithms_test {
       case Mixed: return false;
       case NegativeFirst: return true;
       case AllNegative: return true;
-      case AllPositive: return false;
+      case AllPositive: return true;
       case NegativeLast: return false;
       case SingleNegative: return true;
       default: return false;