Each computer system will have a number of distinct places in which the system will allow you to allocate memory. In Umpire’s world, these are memory resources. A memory resource can correspond to a hardware resource, but can also be used to identify memory with a particular characteristic, like “pinned” memory in a GPU system.

When you configure Umpire, it will create umpire::resource::MemoryResource s according to what is available on the system you are building for. For each resource, Umpire will create a default umpire::Allocator that you can use. In the previous example, we were actually using an umpire::Allocator created for the memory resource corresponding to the CPU memory

The easiest way to identify resources is by name. The “HOST” resource is always available. In a modern NVIDIA GPU system, we also have resources that represent global GPU memory (“DEVICE”), unified memory that can be accessed by the CPU or GPU (“UM”) and host memory that can be accessed by the GPU (“PINNED”);

Umpire will create an umpire::Allocator for each of these resources, and you can get them using the same umpire::ResourceManager::getAllocator() call you saw in the previous example:

  umpire::Allocator allocator = rm.getAllocator(resource);

Note that every allocator supports the same calls, no matter which resource it is for, this means we can run the same code for all the resources available in the system.

In the next example, we will learn how to move data between resources using operations.

// Copyright (c) 2016-20, Lawrence Livermore National Security, LLC and Umpire
// project contributors. See the COPYRIGHT file for details.
// SPDX-License-Identifier: (MIT)
#include "umpire/Allocator.hpp"
#include "umpire/ResourceManager.hpp"

void allocate_and_deallocate(const std::string& resource)
  constexpr std::size_t SIZE = 1024;

  auto& rm = umpire::ResourceManager::getInstance();

  umpire::Allocator allocator = rm.getAllocator(resource);

  double* data = static_cast<double*>(

  std::cout << "Allocated " << (SIZE*sizeof(double)) << " bytes using the "
    << allocator.getName() << " allocator...";


  std::cout << " deallocated." << std::endl;

int main(int, char**) {

#if defined(UMPIRE_ENABLE_HIP)

  return 0;