使用二维NDRange workgroup

作为初学者一直，经过多次的上网搜索你一定会看到迈克老狼的向量加法的示例，不知道你是否和我一样，刚开始并不是很准确的知道他的add.cl写的代码的意思，源码如下：

#pragma OPENCL EXTENSION cl_amd_printf : enable

__kernel void vecadd(__global const float* a, __global const float* b, __global float* c)

{

int x = get_global_id();

int y = get_global_id();

int width = get_global_size();

int height = get_global_size();

if(x ==  && y ==)

printf("%d, %d,%d,%d,%d,%d\n",get_local_size(),get_local_size(),get_local_id(),

get_local_id(),get_group_id(),get_group_id());

c[x + y * width] = a[x + y * width] + b[x + y * width];

}

我们在k

这里面我把二维的这些值全部罗列出来如下：

int idx = get_global_id(0);
int idy = get_global_id(1);

uint wiWidth = get_global_size(0);
uint wiHeight = get_global_size(1);

uint gix_t = get_group_id(0);
uint giy_t = get_group_id(1);

uint num_of_blocks_x = get_num_groups(0);
uint num_of_blocks_y = get_num_groups(1);

uint lix = get_local_id(0);
uint liy = get_local_id(1);

你会奇怪为什么他的add.cl优化会这么写：

c[x + y * width] = a[x + y * width] + b[x + y * width];

下面进行分析：

add.cpp关键的代码部分如下（只罗列出部分代码）：

#define width 8//256

#define height 16//256

#define NWITEMS  width*height//262144

size_t globalThreads[] = {width, height};

	size_t localx, localy;

	localx = 2;

	localy = 4;

	size_t localThreads[] = {localx, localy};

	clEnqueueNDRangeKernel( queue,

	kernel,

	2,

	NULL,

	globalThreads,

	localThreads, 0, NULL, &ev);

我自己的add.cl代码如下（里面添加啦打印，以便我们可以看出结果）：

 　 int idx = get_global_id();

    int idy = get_global_id();

    uint wiWidth  = get_global_size();

    uint wiHeight  = get_global_size();

    printf("Magnum Global idx = %d, idy = %d, sizeX =%d,sizeY =%d\n",idx,idy,wiWidth,wiHeight);

    uint gix_t = get_group_id();

    uint giy_t = get_group_id();

    uint num_of_blocks_x = get_num_groups();

    uint num_of_blocks_y = get_num_groups(); 

    printf("Magnum Group idx = %d, idy = %d, blockX=%d,blockY=%d\n",gix_t,gix_t,num_of_blocks_x,num_of_blocks_y);

    uint lix = get_local_id();

    uint liy = get_local_id();

    uint LocalX = get_local_size();

    uint LocalY = get_local_size();

    printf("Magnum Local idx = %d, idy = %d, localX=%d,localY=%d\n\n",lix,liy,LocalX,LocalY);

输出的结果如下：

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

Magnum Global idx = , idy = , sizeX =,sizeY =

Magnum Group idx = , idy = , blockX=,blockY=

Magnum Local idx = , idy = , localX=,localY=

从从这个结果首先能说明几个问题：

首先我们在：

clEnqueueNDRangeKernel( queue, kernel, , NULL, globalThreads, localThreads, 0, NULL, &ev); 设置维度是2，否则add.cl中所有类似get_local_size(1)将只会返回一。
设置GlobaThreads 和 LocalThreads 不一定是 GlobalThreads= {8, 8}; 也可以不相等，LocalThreads也是一样。
理解opencl中的内存分布可以理解为二维数组，而且内存寻址的方向就像是：左上角（0，0）为原点，一行一行的扫描下去。
WorkGroup的大小，目前我认为X，Y可以分开来理解（后面若发现错误我会及时改正） WorkGroup number(x) = GlobalThread(x)/LocalThread(x).
最小的单位是LocalX * LocalY, 然后用总的GlobalThreads按照这个单位进行分割成一个一个的组。每个二维的小单位还是一行一行的扫描过去的。目前我们的这个是8*16，你会发现总的Thread也是8*16，对应的每一个线程执行一次加法操作，有人会问可不可以不用这么多呢,用4*16个Threads,每个线程里面做两次加法动作，其实是可以的，这个原则是根据你的具体的Device来说的，当前我们说的是Device是GPU，比如你的GPU当前支持最大的线程数是1024*1024，这种情况，你不用多的，而是用少的线程来做，会降低你的效率，你需要尽可能的让Device满负荷工作这样才能达到提高运算速度。

继续分析为什么 NDRange改成二维的之后,add.cl变成：

c[x + y * width] = a[x + y * width] + b[x + y * width];

因为在CPU端每个 C[8*16],通过打印可以在这里C[x+y*width]，x 最大是7，width是8,y最大是17，只有这样才能做完所有的向量相加。

使用二维NDRange workgroup的更多相关文章

OpenCL 学习step by step (5) 使用二维NDRange workgroup
http://www.cnblogs.com/mikewolf2002/archive/2012/09/07/2675634.html 在本教程中,我们使用二维NDRange来设置workgroup, ...
Javascript生成二维码（QR）
网络上已经有非常多的二维码编码和解码工具和代码,很多都是服务器端的,也就是说需要一台服务器才能提供二维码的生成.本着对服务器性能的考虑,这种小事情都让服务器去做,感觉对不住服务器,尤其是对于大流量的网 ...
iOS二维码生成、识别、扫描等
二维码扫描前言: 最近的项目中使用到了二维码,二维码这个模块功能也完成:觉得还是有必要总结一下用来做记录.好长时间没有写二维码了都忘记在差不多了,重新拾起来还是挻快的. 二维码使用场景: 生活中有很 ...
很多人很想知道怎么扫一扫二维码就能打开网站，就能添加联系人，就能链接wifi，今天说下这些格式，明天做个demo
有些功能部分手机不能使用,网站,通讯录,wifi基本上每个手机都可以使用. 在看之前你可以扫一扫下面几个二维码先看看效果: 1.二维码生成网址 (URL) 包含网址的二维码生成是大家平时最常接触 ...
免费开源的DotNet二维码操作组件ThoughtWorks.QRCode（.NET组件介绍之四）
在生活中有一种东西几乎已经快要成为我们的另一个电子”身份证“,那就是二维码.无论是在软件开发的过程中,还是在普通用户的日常中,几乎都离不开二维码.二维码 (dimensional barcode) , ...
基于SignalR的消息推送与二维码描登录实现
1 概要说明使用微信扫描登录相信大家都不会陌生吧,二维码与手机结合产生了不同应用场景,基于二维码的应用更是比较广泛.为了满足ios.android客户端与web短信平台的结合,特开发了基于Singl ...
微信小程序的机会在于重新理解群组与二维码
历时一年,唯一一个尚未发布就获得Pony Ma与Allen Zhang站台的产品:微信小程序,将于2017年1月9日正式上线了.我很期待.唯一要警惕的是:防止长考出臭棋. 在上线前夕,我对于如何借助小 ...
javaScript生成二维码（支持中文，生成logo）
资料搜索选择star最多的两个第一个就是用的比较多的jquery.qrcode.js(但不支持中文,不能带logo)啦,第二个支持ie6+,支持中文,根据第二个源代码,使得,jquery.qrco ...
微信小程序二维码推广统计
微信小程序可以通过生成带参数的二维码,那么这个参数是可以通过APP的页面进行监控的这样就可以统计每个二维码的推广效果. 今天由好推二维码推出的小程序统计工具HotApp小程序统计也推出了带参数二维码 ...

随机推荐

一段sql的优化
优化前代码 select * ,ROW_NUMBER() OVER(order by WrongCount desc) as rowId from(select Quba_IDint,Quba_Num ...
tomcat内存溢出问题
内存泄露java.lang.OutOfMemoryError: PermGen space解决办法今天访问web服务器,tomcat服务就瘫痪了,通过查看日志,发现java.lang.OutOfMe ...
Visual Studio2012中搭建WCF项目
分布式系统:指在系统与系统之间进行通信,系统不再是孤立的,例如:淘宝查看物流信息,或是hao123的天气预报,这些可能都是用的别的系统的web方法. 1.创建空的解决方案 2.新建项目-WCF服务库项 ...
javascript 单行向上滚动文字
<html><head><meta http-equiv="Content-Type" content="text/html; charse ...
SVG
目前SVG在国内的使用并不常见,并且关于svg的相关js库也不多,这里指出两款svg的库Snap.svg和svg.js,Snap.svg张鑫旭的博客上有关于他的使用APi http://www.zha ...
响应式页面字体用什么单位：rem
html:62.5%//10pxbody:1.4rem;//14px... <!doctype html> <html> <head> <title>a ...
写一个TT模板自动生成spring.net下面的配置文件。
这个是目标. 然后想着就怎么开始 1.
xcode升级后, 插件失效修复
1. 首先查看 Xcode 的 UUID,在终端执行 defaults read /Applications/Xcode.app/Contents/Info DVTPlugInCompatibilit ...
Xcode 证书生成、设置、应用
Xcode 证书生成.设置.应用,与大家分享.如果按下面步骤还不能编译成功,我手把手教你. 开发环境: Mac OS lion 10.7.4 XCode 4.3.3 1 点击钥匙图标 ...
realloc 函数的使用
realloc 函数的使用 #include <stdio.h> #include <stdlib.h> #include <iostream> using nam ...

使用二维NDRange workgroup

使用二维NDRange workgroup的更多相关文章

随机推荐

热门专题