text: /**
   * Copyright (c) 2015-present, Facebook, Inc.
   * All rights reserved.
   *
   * This source code is licensed under the BSD+Patents license found in the
   * LICENSE file in the root directory of this source tree.
   */
  
  
  #include "../../FaissAssert.h"
  
  namespace faiss { namespace gpu {
  
  template <typename GpuIndex>
  IndexWrapper<GpuIndex>::IndexWrapper(
    int numGpus,
    std::function<std::unique_ptr<GpuIndex>(GpuResources*, int)> init) {
    FAISS_ASSERT(numGpus <= faiss::gpu::getNumDevices());
    for (int i = 0; i < numGpus; ++i) {
      auto res = std::unique_ptr<faiss::gpu::StandardGpuResources>(
        new StandardGpuResources);
  
      subIndex.emplace_back(init(res.get(), i));
      resources.emplace_back(std::move(res));
    }
  
    if (numGpus > 1) {
      // create proxy
      replicaIndex =
        std::unique_ptr<faiss::IndexReplicas>(new faiss::IndexReplicas);
  
      for (auto& index : subIndex) {
        replicaIndex->addIndex(index.get());
      }
    }
  }
  
  template <typename GpuIndex>
  faiss::Index*
  IndexWrapper<GpuIndex>::getIndex() {
    if ((bool) replicaIndex) {
      return replicaIndex.get();
    } else {
      FAISS_ASSERT(!subIndex.empty());
      return subIndex.front().get();
    }
  }
  
  template <typename GpuIndex>
  void
  IndexWrapper<GpuIndex>::runOnIndices(std::function<void(GpuIndex*)> f) {
  
    if ((bool) replicaIndex) {
      replicaIndex->runOnIndex(
        [f](faiss::Index* index) {
          f(dynamic_cast<GpuIndex*>(index));
        });
    } else {
      FAISS_ASSERT(!subIndex.empty());
      f(subIndex.front().get());
    }
  }
  
  template <typename GpuIndex>
  void
  IndexWrapper<GpuIndex>::setNumProbes(int nprobe) {
    runOnIndices([nprobe](GpuIndex* index) {
        index->setNumProbes(nprobe);
      });
  }
  
  } }
  