Question

在下面的代码中，每个工作项生成一个数组sum_qcos_i 为了添加它们，我首先使用本地数组sum_qcos_tmp进行局部加法然后我在全局一维矩阵sum_qcos_part中复制每个局部数组我需要为我的目的添加矩阵列，这是在使用结果之前每个工作项的内容。这是代码

__kernel __attribute__((vec_type_hint(double4))) void energy_forces( const int atom_number, 
                                         const int nvect,
                                 __global double4 *kvect,__global double *qcos,__global double *qsin,
                                 __global double *cst_ewald ,
                                 __global double4 *positions,
                                 __global double4 *forces_r,               
                                 __global double *sum_qcos_part,__global double *sum_qsin_part)                              
{


  int i = 0 ;
  int gti = 0 , ggi = 0 , lti = 0;

  double kr = (double)0.0 ;
  double ss = (double)0.0 , cc = (double)0.0 ;
  double prod = (double)0.0 ;

  double valqcos = 0. , valqsin = 0. ;  

  double4 zeroes_4 = (double4){ 0.0,0.0,0.0,0.0 };

  double sum_qcos_i[NVECTOR_MAX] ;
  double sum_qsin_i[NVECTOR_MAX] ;    

  #if defined NVECTOR_MAX
  __local double sum_qcos_tmp[NVECTOR_MAX] ;
  __local double sum_qsin_tmp[NVECTOR_MAX] ;         
  #endif

  lti = get_local_id(0);
  ggi = get_group_id(0); 

  for (k=0;k<nvect;k++) {         /*k-vectors*/
 sum_qcos_tmp[k] = .0 ;
 sum_qsin_tmp[k] = .0 ;  
 sum_qcos_i[k] = .0 ;
 sum_qsin_i[k] = .0 ;
            }  

  double fk = (double)0.0 ; 
  double4 fr_i = zeroes_4 ;
  double4 kvec_i = zeroes_4;        

  for (gti = get_global_id(0); gti < atom_number; gti += get_global_size(0))
   {

 pos_i = positions[gti];

 for (k=0;k<nvect;k++) {                           /* sum over k-vectors to compute QCOS and QSIN for Ewald sum*/

   prod = dot((double4)pos_i,(double4)kvect[k]);
   ss = (double)sincos(-prod,&cc);
   valqcos = cc ;
   valqsin = ss ; 
//       valqcos = 1. ;
//       valqsin = 1. ;       
   qcos[gti*NVECTOR_MAX+k] = valqcos ;
   qsin[gti*NVECTOR_MAX+k] = valqsin ;
   sum_qcos_i[k] = valqcos ;                     /*  private variable */
   sum_qsin_i[k] = valqsin ;  

                           }                          /* end sum over k-vectors to compute QCOS and QSIN for Ewald sum*/

}    // end for gti 

  int ii = 0 ;

  for ( ii = 0;ii<get_local_size(0);ii++ )
  { 
if (lti == ii)
  { 
 for (k=0;k<nvect;k++) 
    {                   /* k-vectors */               
       sum_qcos_tmp[k] += sum_qcos_i[k] ;     /* accumulates private data to local variable */
       sum_qsin_tmp[k] += sum_qsin_i[k] ; 
    } 
 barrier(CLK_LOCAL_MEM_FENCE|CLK_GLOBAL_MEM_FENCE) ;    
 }
  }

  if (lti == 0)
   {
     for (k=0;k<nvect;k++) {  
      sum_qcos_part[ggi*NVECTOR_MAX+k] = sum_qcos_tmp[k] ;  /* cp local data to global array */    
      sum_qsin_part[ggi*NVECTOR_MAX+k] = sum_qsin_tmp[k] ;
                           }    
   }

  int iii = 0 ;

  for (gti = get_global_id(0); gti < atom_number; gti += get_global_size(0))
   {

 fr_i = zeroes_4 ;

 barrier(CLK_LOCAL_MEM_FENCE|CLK_GLOBAL_MEM_FENCE) ;

 for (k=0;k<nvect;k++) 
  {   

    sum_qcos_i[k] = .0 ;
    sum_qsin_i[k] = .0 ;

   for (iii=0;iii<get_num_groups(0);iii++)
    {  
      sum_qcos_i[k] += sum_qcos_part[iii*NVECTOR_MAX+k] ;
      sum_qsin_i[k] += sum_qsin_part[iii*NVECTOR_MAX+k] ;     
    }

 } 

 barrier(CLK_LOCAL_MEM_FENCE|CLK_GLOBAL_MEM_FENCE) ;

 for (k=0;k<nvect;k++) 
  {

    fk =  ( sum_qcos_i[k]*qsin[gti*NVECTOR_MAX+k] - sum_qsin_i[k]*qcos[gti*NVECTOR_MAX+k] ) ;               
    fr_i += cst_ewald[k] * fk * kvect[k] ;    

  }

#if defined(SCALAR_KERNELS)
forces_r[gti].x = fr_i.x;
forces_r[gti].y = fr_i.y;
forces_r[gti].z = fr_i.z;     
forces_r[gti].w = .0 ;        
#elif defined(VECTOR_KERNELS)
forces_r[gti] = fr_i;   
#endif

  }    // end for gti  

}

这个内核不起作用，我无法理解为什么一些提示在这里会非常有用谢谢。

Answer 1

添加障碍成了诀窍：

for ( ii = 0;ii<get_local_size(0);ii++ )
{ 
if (lti == ii)
  { 
    barrier(CLK_LOCAL_MEM_FENCE|CLK_GLOBAL_MEM_FENCE) ;      
    for (k=0;k<nvect;k++) 
    {                   /* k-vectors */               
      sum_qcos_tmp[k] += sum_qcos_i[k] ;      /* accumulates private data to local variable */
      sum_qsin_tmp[k] += sum_qsin_i[k] ; 
    } 

  }
}

矢量forces_r的最后一个仍然是错误的，它现在总是一样。

Answer 2

实际上问题没有解决我根据粒子数定义全局工作大小，以便每个工作项处理一个粒子在我的计算中，我点产品每个粒子与一定数量的向量坐标我现在的问题是这些点积的结果取决于组的大小。我把矢量放在double4数组中。全局工作大小从1000到10000，而我用于点积的向量数总是大约200。我想知道是否有关于全局工作大小的数组大小的要求。

for (gti = get_global_id(0); gti < atom_number; gti += get_global_size(0))
 {
   pos_i = positions[gti];

   for (k=0;k<nvect;k++) {                           /* sum over k-vectors to compute QCOS and QSIN for Ewald sum*/

 prod = dot((double4)pos_i,(double4)kvect[k]);
 ss = (double)sincos(-prod,&cc);
 valqcos = cc ;
 valqsin = ss ;   
 qcos[gti*NVECTOR_MAX+k] = valqcos ;
 qsin[gti*NVECTOR_MAX+k] = valqsin ;
 sum_qcos_i[k] = valqcos ;                     /*  private variable */
 sum_qsin_i[k] = valqsin ;  

                         }                          /* end sum over k-vectors to compute QCOS and QSIN for Ewald sum*/
 }    // end for gtiforgot

这里有任何提示吗？

OpenCl：添加大量数组

2 个答案: