讀取原始編碼的nrrd數據文件到雙重

Question

有誰知道如何讀取原始編碼的文件？所以難住....我想讀花車或雙打（我認爲）。我一直堅持這幾個星期。謝謝！ http://www.sci.utah.edu/~gk/DTI-data/gk2/gk2-rcc-mask.raw

說明原始編碼： 你好：//teem.sourceforge.net/nrrd/format.html#encoding（其他城市招呼到http去，我想讀從

文件頁面） - 「raw」 - 根據字節值和字節順序，數據出現在磁盤上，與內存完全相同。由write（）和fwrite（）產生，適用於read（）或fread（）。

信息的文件： http://www.sci.utah.edu/~gk/DTI-data/gk2/gk2-rcc-mask.nhdr - 我認爲唯一重要的事情是大端（仍試圖理解谷歌是什麼意思）和原始編碼。

我目前的做法，不確定的，如果它是正確的：

//Function ripped off from example of c++ ifstream::read reference page 

void scantensor(string filename){ 
    ifstream tdata(filename, ifstream::binary); // not sure if I should put ifstream::binary here 

    // other things I tried 
    // ifstream tdata(filename) ifstream tdata(filename, ios::in) 

    if(tdata){ 
      tdata.seekg(0, tdata.end); 
      int length = tdata.tellg(); 
      tdata.seekg(0, tdata.beg); 

      char* buffer = new char[length]; 

      tdata.read(buffer, length); 

      tdata.close(); 

      double* d; 
      d = (double*) buffer; 

    } else cerr << "failed" << endl; 
} 

/* P.S. I attempted to print the first 100 elements of the array. 

    Then I print 100 other elements at some arbitrary array indices (i.e. 9,900 - 10,000). I actually kept increasing the number of 0's until I ran out of bound at 100,000,000 (I don't think that's how it works lol but I was just playing around to see what happens) 

    Here's the part that makes me suspicious: so the ifstream different has different constructors like the ones I tried above. 

    the first 100 values are always the same. 

    if I use ifstream::binary, then I get some values for the 100 arbitrary printing 
    if I use the other two options, then I get -6.27744e+066 for all 100 of them 

    So for now I am going to assume that ifstream::binary is the correct one. The thing is, I am not sure if the file I provided is how binary files actually look like. I am also unsure if these are the actual numbers that I am supposed to read in or just casting gone wrong. I do realize that my casting from char* to double* can be unsafe, and I got that from one of the threads. 

*/ 

我真的很感激！

編輯1：現在在用上述方法正在讀取的數據顯然是「不正確」，因爲在paraview包的值是：

Dxx,Dxy,Dxz,Dyy,Dyz,Dzz 
[0, 1], [-15.4006, 13.2248], [-5.32436, 5.39517], [-5.32915, 5.96026], [-17.87, 19.0954], [-6.02961, 5.24771], [-13.9861, 14.0524] 

It's a 3 x 3 symmetric matrix, so 7 distinct values, 7 ranges of values. 

我目前正在從文件解析彩車現在是非常大（即-4.68855e-229，-1.32351e + 120）。

也許有人知道如何從Paraview中提取花車？

Answer 1

既然你想和雙打的工作，我建議從文件中讀取的數據作爲雙打的緩衝：

const long machineMemory = 0x40000000; // 1 GB 

FILE* file = fopen("c:\\data.bin", "rb"); 

if (file) 
{ 
    int size = machineMemory/sizeof(double); 

    if (size > 0) 
    { 
     double* data = new double[size]; 

     int read(0); 
     while (read = fread(data, sizeof(double), size, file)) 
     { 
     // Process data here (read = number of doubles) 
     } 

     delete [] data; 
    } 

    fclose(file); 
}