From c0d76ef9841e66dc50590e0b9b21541cddb9af97 Mon Sep 17 00:00:00 2001
From: Alexander Smorkalov <alexander.smorkalov@itseez.com>
Date: Tue, 13 Jan 2015 13:00:06 +0300
Subject: [PATCH] driver_api_stereo_multi sample reworked to use parallel_for_
 instead of parallel_do

---
 samples/gpu/driver_api_stereo_multi.cpp | 55 +++++++++++--------------
 1 file changed, 23 insertions(+), 32 deletions(-)

diff --git a/samples/gpu/driver_api_stereo_multi.cpp b/samples/gpu/driver_api_stereo_multi.cpp
index d4d0af451..c02348cf0 100644
--- a/samples/gpu/driver_api_stereo_multi.cpp
+++ b/samples/gpu/driver_api_stereo_multi.cpp
@@ -13,25 +13,12 @@
 #include "opencv2/highgui/highgui.hpp"
 #include "opencv2/gpu/gpu.hpp"
 
-#if !defined(HAVE_CUDA) || !defined(HAVE_TBB) || defined(__arm__)
-
+#if defined(__arm__)
 int main()
 {
-#if !defined(HAVE_CUDA)
-    std::cout << "CUDA support is required (CMake key 'WITH_CUDA' must be true).\n";
-#endif
-
-#if !defined(HAVE_TBB)
-    std::cout << "TBB support is required (CMake key 'WITH_TBB' must be true).\n";
-#endif
-
-#if defined(__arm__)
     std::cout << "Unsupported for ARM CUDA library." << std::endl;
-#endif
-
     return 0;
 }
-
 #else
 
 #include <cuda.h>
@@ -42,7 +29,6 @@ using namespace std;
 using namespace cv;
 using namespace cv::gpu;
 
-struct Worker { void operator()(int device_id) const; };
 void destroyContexts();
 
 #define safeCall(expr) safeCall_(expr, #expr, __FILE__, __LINE__)
@@ -77,6 +63,27 @@ GpuMat d_right[2];
 StereoBM_GPU* bm[2];
 GpuMat d_result[2];
 
+
+struct Worker: public ParallelLoopBody
+{
+    virtual void operator() (const Range& range) const
+    {
+        for (int device_id = range.start; device_id != range.end; ++device_id)
+        {
+            contextOn(device_id);
+
+            bm[device_id]->operator()(d_left[device_id], d_right[device_id],
+                                      d_result[device_id]);
+
+            std::cout << "GPU #" << device_id << " (" << DeviceInfo().name()
+            << "): finished\n";
+
+            contextOff();
+
+        }
+    }
+};
+
 static void printHelp()
 {
     std::cout << "Usage: driver_api_stereo_multi_gpu --left <left_image> --right <right_image>\n";
@@ -162,8 +169,7 @@ int main(int argc, char** argv)
     contextOff();
 
     // Execute calculation in two threads using two GPUs
-    int devices[] = {0, 1};
-    parallel_do(devices, devices + 2, Worker());
+    parallel_for_(cv::Range(0, 2, Worker());
 
     // Release the first GPU resources
     contextOn(0);
@@ -188,21 +194,6 @@ int main(int argc, char** argv)
     return 0;
 }
 
-
-void Worker::operator()(int device_id) const
-{
-    contextOn(device_id);
-
-    bm[device_id]->operator()(d_left[device_id], d_right[device_id],
-                              d_result[device_id]);
-
-    std::cout << "GPU #" << device_id << " (" << DeviceInfo().name()
-        << "): finished\n";
-
-    contextOff();
-}
-
-
 void destroyContexts()
 {
     safeCall(cuCtxDestroy(contexts[0]));