what（）：std :: bad_alloc - 我内存不足？ [英] what(): std::bad_alloc - am I out of memory?

问题描述

我的数据集：500,000点在960维度。该文件的大小为1.9 GB（1,922,000,000字节）。

My dataset: 500,000 points in 960 dimensions. The size of the file is 1.9 GB (1,922,000,000 bytes).

该代码适用于较小的数据集，但为此，它会在每次崩溃的同一点。以下是一个最小示例：

The code works for smaller data sets, but for this it will crash in the same point every time. Here is a minimal example:

#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

我内存不足吗？

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

推荐答案

std :: bad_alloc意味着分配内存的问题 - 所以是的，你很可能内存不足。不幸的是，没有可靠的方法来处理这种异常 - 你可以抓住它，并感激地退出应用程序。

std::bad_alloc means a problem with allocating a memory - so yes, you're most likely out of memory. Unfortunately, there is no a reliable way to "handle" this kind of exception - you can catch it and gratefully exit application.

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