Updating lesson 3

Intro_Tutorial/lessons/03_umpire_allocator/03_umpire_allocator.cpp

@@ -9,7 +9,12 @@ int main()
 
   // TODO: allocate an array of 100 doubles using the HOST allocator
 
-  std::cout << "Address of data: " << data << std::endl;
+  // TODO: use the resource manager to memset your array to 0
+
+  // TODO: uncomment this print statement
+  //std::cout << "Allocated " << (100 * sizeof(double)) << " bytes and set to "
+  //          << data[0] << " using the " << allocator.getName() << " allocator."
+  //          << std::endl;
 
   // TODO: deallocate the array
 

Intro_Tutorial/lessons/03_umpire_allocator/README.md

@@ -7,7 +7,7 @@ deallocate memory.
 The fundamental concept for accessing memory through Umpire is the
 `umpire::Allocator`. An `umpire::Allocator` is a C++ object that can be used to
 allocate and deallocate memory, as well as query a pointer to get
-information about it.
+information about it. (Note: in this lesson, we will see how to query the name of the Allocator!)
 
 All `umpire::Allocator` objects are created and managed by Umpire’s
 `umpire::ResourceManager`. To create an allocator, first obtain a handle to the
@@ -30,6 +30,14 @@ the desired size for your allocation:
 void* memory = allocator.allocate(size in bytes);
 ```
 
+Moving and modifying data in a heterogenous memory system can be annoying since you 
+have to keep track of the source and destination, and often use vendor-specific APIs 
+to perform the modifications. In Umpire, all data modification and movement, regardless
+of memory resource or platform, is done using Operations. 
+
+Next, we will use the `memset` Operator provided by Umpire's Resource Manager to
+set the memory we just allocated to zero.
+
 Don't forget to deallocate your memory afterwards!
 
 For more details, you can check out the Umpire documentation:
@@ -40,5 +48,5 @@ Once you have made your changes, you can compile and run the lesson:
 ```
 $ make 03_umpire_allocator
 $ ./bin/03_umpire_allocator
-Address of data: 0x?????
+Allocated 800 bytes and set to 0 using the HOST allocator.
 ```

Intro_Tutorial/lessons/03_umpire_allocator/solution/03_umpire_allocator_solution.cpp

@@ -12,7 +12,13 @@ int main()
   auto allocator = rm.getAllocator("HOST");
   data = static_cast<double*>(allocator.allocate(100*sizeof(double)));
 
-  std::cout << "Address of data: " << data << std::endl;
+  // TODO: use the resource manager to memset your array to 0
+  rm.memset(data, 0);
+
+  // TODO: uncomment this print statement
+  std::cout << "Allocated " << (100 * sizeof(double)) << " bytes and set to "
+            << data[0] << " using the " << allocator.getName() << " allocator."
+            << std::endl;
 
   // TODO: deallocate the array
   allocator.deallocate(data);