add thrust

src/Core/testing/CMakeLists.txt

@@ -31,3 +31,8 @@ set(LIBRARIES
        ${ROOT_LIBRARIES}
 )
 uLib_add_tests(Core)
+
+if(USE_CUDA)
+    set_source_files_properties(VectorMetaAllocatorTest.cpp PROPERTIES LANGUAGE CUDA)
+endif()
+

src/Core/testing/VectorMetaAllocatorTest.cpp

@@ -12,6 +12,15 @@
 #include "testing-prototype.h"
 #include <Core/Vector.h>
 
+#ifdef USE_CUDA
+#include <thrust/device_ptr.h>
+#include <thrust/transform.h>
+
+struct DoubleFunctor {
+  __host__ __device__ int operator()(int x) const { return x * 2; }
+};
+#endif
+
 int main() {
   BEGIN_TESTING(VectorMetaAllocator);
 
@@ -41,14 +50,31 @@ int main() {
     exit(1);
   }
 
+  // Verify DeviceData() matches GetVRAMData()
+  {
+    thrust::device_ptr<int> dev_ptr = v.DeviceData();
+    if (dev_ptr.get() != vram_ptr) {
+      std::cout << "Error: DeviceData() does not match GetVRAMData()!\n";
+      exit(1);
+    }
+    std::cout << "DeviceData() matches GetVRAMData(). OK\n";
+  }
+
+  // Use thrust::transform via DeviceBegin()/DeviceEnd() to double all elements
+  // on device
+  std::cout << "Doubling elements on device via thrust::transform...\n";
+  thrust::transform(v.DeviceBegin(), v.DeviceEnd(), v.DeviceBegin(),
+                    DoubleFunctor{});
+
   std::cout << "Moving back to RAM...\n";
   v.MoveToRAM();
 
-  std::cout << "RAM contents after VRAM trip: ";
+  std::cout << "RAM contents after VRAM trip + thrust transform: ";
   for (size_t i = 0; i < v.size(); ++i) {
     std::cout << v[i] << " ";
-    if (v[i] != (int)(i + 1)) {
-      std::cout << "\nError: Data corrupted after RAM->VRAM->RAM trip at index "
+    if (v[i] != (int)((i + 1) * 2)) {
+      std::cout << "\nError: Data corrupted after RAM->VRAM->thrust->RAM trip "
+                   "at index "
                 << i << "\n";
       exit(1);
     }