在 Rcpp 中使用 Eigen c++ 库用于 Galerkin 矩阵时出现问题

我正在尝试在RStudio中计算以下C++代码。

// [[Rcpp::depends(RcppEigen)]]
#include <RcppEigen.h>
using namespace Rcpp;
// [[Rcpp::export]]
#include <iostream>
#include <cmath>
using Eigen::Dense;
using Eigen::SparseLU;
using Eigen::Sparse;
using Eigen::SparseMatrix;
using namespace std;
Eigen::SparseMatrix<double> getGalMat(int N) {
  // Note: N hast to bigger or equal to 5!!!
  assert(N >= 5);
  typedef Eigen::SparseMatrix<double>::Index index_t;
  typedef Eigen::Triplet<double> triplet_t;
  std::vector<triplet_t> triplets;
  // reserve "minimal" vector size (the number of non-zero entries)
  triplets.reserve(5*N - 6);
  // N minus 1
  int Nm = N - 1;
  // set the (off-) diagonals
  double diag_m2 = + 16;
  double diag_m1 = - 64;
  double diag    = + 96;
  double diag_p1 = - 64;
  double diag_p2 = + 16;
  // set first and last 2 rows by hand
  // A(1  ,:)
  triplets.push_back({0   ,0   ,diag   }); // A(1,1)
  triplets.push_back({0   ,1   ,diag_p1}); // A(1,2)
  triplets.push_back({0   ,2   ,diag_p2}); // A(1,3)
  // A(2  ,:)
  triplets.push_back({1   ,0   ,diag_m1}); // A(2,1)
  triplets.push_back({1   ,1   ,diag   }); // A(2,2)
  triplets.push_back({1   ,2   ,diag_p1}); // A(2,3)
  triplets.push_back({1   ,3   ,diag_p2}); // A(2,4)
  // A(N-1,:)
  triplets.push_back({Nm-1,Nm-3,diag_m2}); // A(N-1,N-3)
  triplets.push_back({Nm-1,Nm-2,diag_m1}); // A(N-1,N-2)
  triplets.push_back({Nm-1,Nm-1,diag   }); // A(N-1,N-1)
  triplets.push_back({Nm-1,Nm  ,diag_p1}); // A(N-1,N  )
  // A(N  ,:)
  triplets.push_back({Nm  ,Nm-2,diag_m2}); // A(N,N-2)
  triplets.push_back({Nm  ,Nm-1,diag_m1}); // A(N,N-1)
  triplets.push_back({Nm  ,Nm  ,diag   }); // A(N,N  )
  // loop over remaining rows
  for (int i = 2; i < Nm-1; i++) {
    triplets.push_back({i,i-2,diag_m2}); // A(i,i-2)
    triplets.push_back({i,i-1,diag_m1}); // A(i,i-1)
    triplets.push_back({i,i  ,diag   }); // A(i,i  )
    triplets.push_back({i,i+1,diag_p1}); // A(i,i+1)
    triplets.push_back({i,i+2,diag_p2}); // A(i,i+2)
  }
  // let EIGEN build the sparse matrix from our triplets
  Eigen::SparseMatrix<double> spMat(N,N);
  spMat.setFromTriplets(triplets.begin(), triplets.end());
  // return
  return spMat;
}

运行它时，我有一长串来自第 41 行单词的错误，对应于：

triplets.push_back({0   ,0   ,diag   }); // A(1,1)

收到错误："扩展初始值设定项列表仅适用于 -std=C++0x 或 -std=GNU++0x [默认启用]"

有人有建议吗？

提前感谢您的帮助。