disjoint checker is smarter (and slower)

1 files changed, 28 insertions, 0 deletions

diff --git a/tests/parallel/tparfind.nim b/tests/parallel/tparfind.nim
new file mode 100644
index 000000000..9de5012f5
--- /dev/null
+++ b/tests/parallel/tparfind.nim
@@ -0,0 +1,28 @@
+discard """
+  output: "500"
+"""
+
+import threadpool, sequtils
+
+{.experimental.}
+
+proc linearFind(a: openArray[int]; x, offset: int): int =
+  for i, y in a:
+    if y == x: return i+offset
+  result = -1
+
+proc parFind(a: seq[int]; x: int): int =
+  var results: array[4, int]
+  parallel:
+    if a.len >= 4:
+      let chunk = a.len div 4
+      results[0] = spawn linearFind(a[0 ..< chunk], x, 0)
+      results[1] = spawn linearFind(a[chunk ..< chunk*2], x, chunk)
+      results[2] = spawn linearFind(a[chunk*2 ..< chunk*3], x, chunk*2)
+      results[3] = spawn linearFind(a[chunk*3 ..< a.len], x, chunk*3)
+  result = max(results)
+
+
+let data = toSeq(0..1000)
+echo parFind(data, 500)
+