c++ - what(): std::bad_alloc - 我的内存力不足了吗？

Question

我的数据集:960 个维度中的 500,000 个点。文件大小为 1.9 GB(1,922,000,000 字节)。

该代码适用于较小的数据集，但为此它每次都会在同一点崩溃。这是一个最小的例子:

#include <iostream>
#include <vector>

template<typename T>
class Division_Euclidean_space {
 public:
  /**
   * The data type.
   */
  typedef T FT;

  /**
   * Constructor, which
   * sets 'N' and 'D' to zero.
   */
  Division_Euclidean_space()
      : N(0),
        D(0) {

  }

  /**
   * @param n - size of data
   */
  void setSize(size_t& n) {
    N = n;
  }

  /**
   * @param n - size of data
   */
  void setSize(int n) {
    N = n;
  }

  /**
   * Get the number of points
   *
   * @return - the number of points
   */
  const size_t& size() const {
    return N;
  }

  /**
   * Get the dimension of points
   *
   * @return - the dimension
   */
  const int dim() {
    return D;
  }

  /**
   * @param d - dimension of data
   */
  void setDim(int& d) {
    D = d;
  }

  /**
   * \brief Inserts a new value to the collection of
   * points, held in the private vector.
   *
   * @param v - value to be inserted
   */
  void insert(FT v) {
    p.push_back(v);
  }

 private:
  /**
   * number of points
   */
  size_t N;
  /**
   * dimension of points
   */
  int D;
  /**
   * vector of points
   * Note that indexing is of the form: [i * D + j]
   */
  std::vector<FT> p;
};

typedef Division_Euclidean_space<int> Division_space;
typedef Division_space::FT FT;

template<typename T>
void readDivisionSpacefvecs(Division_Euclidean_space<T>& ds, int& N, int& D,
                            char* filename) {
  FILE* fid;
  fid = fopen(filename, "rb");
  if (!fid)
    printf("I/O error : Unable to open the file %s\n", filename);

  // we assign the return value of fread() to 'sz' just to suppress a warning
  size_t sz = fread(&D, sizeof(D), 1, fid);
  fseek(fid, 0L, SEEK_END);
  sz = ftell(fid);
  N = sz / (1 * 4 + D * 4);
  //printf("N = %d, D = %d, |%s|\n", N, D, filename);

  fseek(fid, 0L, SEEK_SET);
  ds.setSize(N);
  ds.setDim(D);
  std::cout << ds.dim() << " " << ds.size() << "\n";
  int c = 0;
  float v;
  int i, j;
  for (i = 0; i < N; ++i) {
    sz = fread(&D, sizeof(D), 1, fid);
    //printf("%d\n", D);
    for (j = 0; j < D; ++j) {
      sz = fread(&v, sizeof(v), 1, fid);
      if (c >= 279619)
        printf("j = %d, v = %f, read up to point %d\n", j, v, c);
      ds.insert(v);
    }
    ++c;
    printf("read up to %d\n", c);
  }
  if (c != N)
    printf("WARNING! Read less points than expected.\n");
}

int main() {
  Division_space test;
  int N, D;
  readDivisionSpacefvecs<FT>(test, N, D, "../../parallel/rkd_forest/Datasets/gist/gist_learn.fvecs");

  return 0;
}

输出:

...
j = 255, v = 0.052300, read up to point 279620
j = 256, v = 0.052300, read up to point 279620
terminate called after throwing an instance of 'std::bad_alloc'
  what(): std::bad_alloc
Aborted

我是不是记错了？我怎么知道？

这是我有多少内存:

samaras@samaras-A15:~$ free -mt
             total       used       free     shared    buffers     cached
Mem:          3934       2638       1295          0        179       1000
-/+ buffers/cache:       1458       2475
Swap:         3987          0       3987
Total:        7922       2638       5283

Answer 1

std::bad_alloc 表示分配内存时出现问题 - 所以是的，您很可能内存不足。不幸的是，没有一种可靠的方法来“处理”这种异常——您可以捕获它并欣然退出应用程序。