Hi, I found this code in NVIDIA's cuda SDK samples.

    void computeGold( float* reference, float* idata, const unsigned int len)                                                                                                                                                                                                           
{                                                                                                                                                                                                                                                                              
  reference[0] = 0;                                                                                                                                                                                                                                                            
  double total_sum = 0;                                                                                                                                                                                                                                                        
  unsigned int i;                                                                                                                                                                                                                                                              
  for( i = 1; i < len; ++i)                                                                                                                                                                                                                                                    
  {                                                                                                                                                                                                                                                                            
      total_sum += idata[i-1];                                                                                                                                                                                                                                                 
      reference[i] = idata[i-1] + reference[i-1];                                                                                                                                                                                                                              
  }                                                                                                                                                                                                                                                                            
  // Here it should be okay to use != because we have integer values                                                                                                                                                                                                           
  // in a range where float can be exactly represented                                                                                                                                                                                                                         
  if (total_sum != reference[i-1])                                                                                                                                                                                                                                             
      printf("Warning: exceeding single-precision accuracy.  Scan will be inaccurate.\n");                                                                                                                                                                                     

}   

(C) Nvidia Corp

Can somebody please tell me a case where the warning would be printed, and most importantly, why. Thank you very much.