From b28fd79fdc01e70bf724b193f49654f4a0117713 Mon Sep 17 00:00:00 2001
From: Alexander Alekhin <alexander.alekhin@intel.com>
Date: Tue, 28 Feb 2017 17:27:26 +0300
Subject: [PATCH] core: parallel_for_(): propagate RNG state from the main
 thread

---
 modules/core/src/parallel.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/modules/core/src/parallel.cpp b/modules/core/src/parallel.cpp
index 71ac94eec8..0d3a93a085 100644
--- a/modules/core/src/parallel.cpp
+++ b/modules/core/src/parallel.cpp
@@ -174,6 +174,9 @@ namespace
             double len = wholeRange.end - wholeRange.start;
             nstripes = cvRound(_nstripes <= 0 ? len : MIN(MAX(_nstripes, 1.), len));
 
+            // propagate main thread state
+            rng = cv::theRNG();
+
 #ifdef ENABLE_INSTRUMENTATION
             pThreadRoot = cv::instr::getInstrumentTLSStruct().pCurrentNode;
 #endif
@@ -195,6 +198,9 @@ namespace
 #endif
             CV_INSTRUMENT_REGION()
 
+            // propagate main thread state
+            cv::theRNG() = rng;
+
             cv::Range r;
             r.start = (int)(wholeRange.start +
                             ((uint64)sr.start*(wholeRange.end - wholeRange.start) + nstripes/2)/nstripes);
@@ -208,6 +214,7 @@ namespace
         const cv::ParallelLoopBody* body;
         cv::Range wholeRange;
         int nstripes;
+        cv::RNG rng;
 #ifdef ENABLE_INSTRUMENTATION
         cv::instr::InstrNode *pThreadRoot;
 #endif