title: PCACompute Opencv return eigenvectors = 0
body: <p>have this problem with PCACompute in Android Opencv2.3.1 because when i call PCACompute my eigenvectors are all 0. So, i take 10 photos for each people and i save it into a Mat of 100X100.
  After that, i convert my 100X100 Mat in one Mat 1X10000 with this code: </p>
  
  <pre><code>double [] elem = null; 
   for(int riga=0;riga&lt;m.rows();riga++)
    {
     for(int colonna=0;colonna&lt;m.cols();colonna++)
     {
      elem = m.get(riga, colonna);
        mrow.put(0,((riga*100)+colonna), elem[0]);
      }//for colonna
   }//for riga
  </code></pre>
  
  <p>After that, when i take 10 photos, i insert all Mat of the photos into one mat with this code: </p>
  
  <pre><code>double b[] = null;
    for (int i = 0; i&lt; listafoto.size(); i++)
     {
      Mat t = listafoto.get(i);
        for(int riga = 0;riga&lt;t.rows();riga++)
         {
          for(int colonna =0;colonna&lt;t.cols();colonna++)
          {
             b = t.get(riga, colonna);
             datiOriginali.put(i, colonna, b[0]);
          }//for colonna
      }//for riga
   }//for lista e contemporaneamente riga datiOriginali
  </code></pre>
  
  <p>After that, i call PCACompute with this code: ` </p>
  
  <pre><code> org.opencv.core.Core.PCACompute(datiOriginali,mean, eigenvectors, 10);`
  </code></pre>
  
  <p>So, datiOriginali is the input Mat of 10 rows and 10000 cols, mean and eigenvectors are the output matrix. mean matrix give me a result, but eigenvectors give me all 0. Can you help me to resolve this problem?
  Thanks in advance.MArco</p>