如何设置cmake链接并行升压图？

Question

我正在尝试设置CMake，这样就可以正确地链接升压图。但是我在做的时候遇到了一个错误

find_package(Boost REQUIRED COMPONENTS graph mpi) # finding mpi is a problem

-- Found boost_mpi 1.77.0 at ~/miniconda3/envs/xyz/lib/cmake/boost_mpi-1.77.0
--   Library has no variants and is considered not found
CMake Error at /home/tom/miniconda3/envs/pokeai/lib/cmake/Boost-1.77.0/BoostConfig.cmake:141 (find_package):
  Found package configuration file:

    ~/miniconda3/envs/xyz/lib/cmake/boost_mpi-1.77.0/boost_mpi-config.cmake

  but it set boost_mpi_FOUND to FALSE so package "boost_mpi" is considered to
  be NOT FOUND.  Reason given by package:

  No suitable build variant has been found.

我已经尝试从Boost图中找到一个文档，但是似乎cmake部分不适合安装。来自boost_mpi-config.cmake的一条线在我看来是可疑的，这与错误有关。

要在本地产生问题，您可能会发现下面的文件很有用。

CMakeLists.txt使用：

cmake_minimum_required(VERSION 3.23)

set(Boost_VERBOSE ON)
message(CHECK_START "Looking for MPI")
find_package(MPI REQUIRED COMPONENTS CXX C)

#find_package(Boost REQUIRED COMPONENTS graph)
find_package(Boost REQUIRED COMPONENTS graph mpi) # finding mpi is a problem
add_executable(parallel_boost_graph parallel_boost_graph.cpp)

target_link_libraries(parallel_boost_graph
        PUBLIC
        MPI::MPI_CXX
        ${Boost_LIBRARIES}
        Boost::graph
        #        Boost::mpi
        )

重现问题的一个小示例代码：

// Enable PBGL interfaces to BGL algorithms
#include <boost/graph/use_mpi.hpp>

// Communication via MPI
#include <boost/graph/distributed/mpi_process_group.hpp>

// Dijkstra's single-source shortest paths algorithm
#include <boost/graph/dijkstra_shortest_paths.hpp>

// Distributed adjacency list
#include <boost/graph/distributed/adjacency_list.hpp>

// METIS Input
#include <boost/graph/metis.hpp>

// Graphviz Output
#include <boost/graph/distributed/graphviz.hpp>

// Standard Library includes
#include <fstream>
#include <string>

#ifdef BOOST_NO_EXCEPTIONS
void boost::throw_exception(std::exception const& ex) {
  std::cout << ex.what() << std::endl;
  abort();
}
#endif

using namespace boost;
using boost::graph::distributed::mpi_process_group;

/* An undirected, weighted graph with distance values stored on the
vertices. */
typedef adjacency_list<vecS, distributedS<mpi_process_group, vecS>, undirectedS,
                       /*Vertex properties=*/property<vertex_distance_t, float>,
                       /*Edge properties=*/property<edge_weight_t, float> >
    Graph;

using namespace boost;
using boost::graph::distributed::mpi_process_group;

int main(int argc, char* argv[]) {
  boost::mpi::environment env(argc, argv);

  typedef adjacency_list<listS, distributedS<mpi_process_group, vecS>,
                         directedS,
                         no_property,                  // Vertex properties
                         property<edge_weight_t, int>  // Edge properties
                         >
      graph_t;
  typedef graph_traits<graph_t>::vertex_descriptor vertex_descriptor;
  typedef graph_traits<graph_t>::edge_descriptor edge_descriptor;

  typedef std::pair<int, int> Edge;
  const int num_nodes = 5;
  enum nodes { A, B, C, D, E };
  char name[] = "ABCDE";
  Edge edge_array[] = {Edge(A, C), Edge(B, B), Edge(B, D),
                       Edge(B, E), Edge(C, B), Edge(C, D),
                       Edge(D, E), Edge(E, A), Edge(E, B)};
  int weights[] = {1, 2, 1, 2, 7, 3, 1, 1, 1};
  int num_arcs = sizeof(edge_array) / sizeof(Edge);

  graph_t g(edge_array, edge_array + num_arcs, weights, num_nodes);
  // Keeps track of the predecessor of each vertex
  std::vector<vertex_descriptor> p(num_vertices(g));
  // Keeps track of the distance to each vertex
  std::vector<int> d(num_vertices(g));

  vertex_descriptor s = vertex(A, g);
  dijkstra_shortest_paths(g, s,
                          predecessor_map(make_iterator_property_map(
                                              p.begin(), get(vertex_index, g)))
                              .distance_map(make_iterator_property_map(
                                  d.begin(), get(vertex_index, g))));

  std::cout << std::endl;

  return EXIT_SUCCESS;
}

为了您的方便，您还可以查看这个回购程序来重现问题：https://bitbucket.org/cpchung/debugging-only

Answer 1

并行Boost.Graph库需要Boost.MPI。

没有找到合适的构建变体。

当在libboost_mpi-variant-*.cmake旁边没有boost_mpi-config.cmake文件时就会发生这种情况，在打包过程中出现错误时(例如，将文件复制到最终目标时忽略了这些文件)，或者Boost.MPI库根本没有构建。我怀疑后者。

因此，您需要做的是通过您使用的任何包管理器获得包含Boost.MPI的Boost安装，如果Boost库被拆分成单独的包，它可以简单地安装一个额外的包。或者您可以自己构建和安装Boost，确保b2命令能够找到MPI头，从而生成Boost.MPI。

注意:使用CMake变量Boost_DEBUG和Boost_VERBOSE (通过cmake -DBoost_DEBUG=ON设置它们)可以帮助查找没有找到或拒绝库的原因。