标签：style blog http ar os 使用 sp for strong
本文的起源来自最近一个让我非常不爽的事。
我最近在改一个开源RNN工具包currennt（http://sourceforge.net/projects/currennt/），想用它实现RNNLM功能。
currennt使用了大量的面向对象的编程技巧，可以使用GPU，向量运算使用了thrust库（https://code.google.com/p/thrust/）。
RNNLM（http://rnnlm.org/）也有相应开源实现，非常算法风格的代码，向量运算就是自己使用数组实现的。
结果……大出我的语料，在不使用GPU的情况下，currennt慢成狗！我不断的修改，直到最后几乎完全在currennt里重写了一个RNNLM……速度才终于一致了。这花费了我大量时间，最关键的是我根本没打算花这些时间，算是计划外开销。
所以这里干脆对常用的几种向量运算做个评测，下回遇到至少心里有数。
参与评测的向量实现包括：
评测指标包括：
测试环境：
VS2010
python 2.7.6
Intel Xeon CPU E5649@2.53GHz x24
thrust v1.5
C++ array
创建全0向量：0.000s，几乎不占用时间
int vector_size=100000000; float* vector=(float*)calloc(vector_size,sizeof(float));
创建+填充向量：0.140s
int vector_size=100000000;
float* vector=(float*)calloc(vector_size,sizeof(float));
for (int i=0;i<vector_size;++i){
vector[i]=0.01;
}
向量点乘：0.390s
float sum=0;
for(int i=0;i<vector_size;++i){
sum+=vector1[i]*vector2[i];
}
向量相乘：0.265s
float sum=0;
for(int i=0;i<vector_size;++i){
vector3[i]=vector1[i]*vector2[i];
}
矩阵乘向量：0.344s
int matrix1_colnum=50000;
int matrix1_rownum=2000;
int matrix1_size=matrix1_colnum*matrix1_rownum;
float* vector1=(float*)calloc(matrix1_size,sizeof(float));
for (int i=0;i<matrix1_size;++i){
vector1[i]=0.01;
}
float* vector2=(float*)calloc(matrix1_colnum,sizeof(float));
for (int i=0;i<matrix1_colnum;++i){
vector2[i]=0.02;
}
start_t=clock();
float* vector3=(float*)calloc(matrix1_rownum,sizeof(float));
for(int row=0;row<matrix1_rownum;++row){
for(int col=0;col<matrix1_colnum;++col){
vector3[row]+=vector1[row*matrix1_colnum+col]*vector2[col];
}
}
end_t=clock();
矩阵乘矩阵：0.749
（耗费时间与matrix1_rownum*matrix1_colnum*matrix2_colnum成正比）
int matrix1_rownum=200;
int matrix1_colnum=5000;
int matrix1_size=matrix1_colnum*matrix1_rownum;
float* vector1=(float*)calloc(matrix1_size,sizeof(float));
for (int i=0;i<matrix1_size;++i){
vector1[i]=0.01;
}
int matrix2_rownum=5000;
int matrix2_colnum=200;
int matrix2_size=matrix2_rownum*matrix2_colnum;
float* vector2=(float*)calloc(matrix2_size,sizeof(float));
for (int i=0;i<matrix2_size;++i){
vector2[i]=0.02;
}
int matrix3_size=matrix1_rownum*matrix2_colnum;
float* vector3=(float*)calloc(matrix3_size,sizeof(float));
start_t=clock();
for(int row1=0;row1<matrix1_rownum;++row1){
for(int col2=0;col2<matrix2_colnum;++col2){
for(int col1=0;col1<matrix1_colnum;++col1){
vector3[row1*matrix2_colnum+col2]+=vector1[row1*matrix1_colnum+col1]*vector2[col1*matrix2_colnum+col2];
}
}
}
end_t=clock();
C++ STL vector
创建全0向量：0.140s
int vect_size=100000000;
vector<float> vector(vect_size);
创建+填充向量：0.140s
int vect_size=100000000; vector<float> vector(vect_size,0.01);
向量点乘：0.375s
int vect_size=100000000;
vector<float> vector1(vect_size,0.01);
vector<float> vector2(vect_size,0.02);
start_t=clock();
float sum=0;
for(int i=0;i<vect_size;++i){
sum+=vector1[i]*vector2[i];
}
end_t=clock();
向量相乘：0.250s
int vect_size=100000000;
vector<float> vector1(vect_size,0.01);
vector<float> vector2(vect_size,0.02);
vector<float> vector3(vect_size);
start_t=clock();
for(int i=0;i<vect_size;++i){
vector3[i]=vector1[i]*vector2[i];
}
end_t=clock();
矩阵乘向量：0.390s
int matrix1_colnum=50000;
int matrix1_rownum=2000;
int matrix1_size=matrix1_colnum*matrix1_rownum;
vector<float> vector1(matrix1_size,0.01);
vector<float> vector2(matrix1_colnum,0.02);
vector<float> vector3(matrix1_rownum);
start_t=clock();
for(int row=0;row<matrix1_rownum;++row){
for(int col=0;col<matrix1_colnum;++col){
vector3[row]+=vector1[row*matrix1_colnum+col]*vector2[col];
}
}
end_t=clock();
矩阵乘法：0.827s
int matrix1_rownum=200;
int matrix1_colnum=5000;
int matrix1_size=matrix1_colnum*matrix1_rownum;
vector<float> vector1(matrix1_size,0.01);
int matrix2_rownum=5000;
int matrix2_colnum=200;
int matrix2_size=matrix2_rownum*matrix2_colnum;
vector<float> vector2(matrix2_size,0.02);
int matrix3_size=matrix1_rownum*matrix2_colnum;
vector<float> vector3(matrix3_size);
start_t=clock();
for(int row1=0;row1<matrix1_rownum;++row1){
for(int col2=0;col2<matrix2_colnum;++col2){
for(int col1=0;col1<matrix1_colnum;++col1){
vector3[row1*matrix2_colnum+col2]+=vector1[row1*matrix1_colnum+col1]*vector2[col1*matrix2_colnum+col2];
}
}
}
end_t=clock();
C++ thrust(CPU)
创建全0向量：0.140s
int vect_size=100000000; thrust::host_vector<float> vector1(vect_size);
创建+填充向量：0.140s
int vect_size=100000000; thrust::host_vector<float> vector1(vect_size，0.01);
填充向量：0.078s
thrust::fill(vector1.begin(),vector1.end(),0.01);
向量点乘：0.359s
int vect_size=100000000; thrust::host_vector<float> vector1(vect_size,(float)0.1); thrust::host_vector<float> vector2(vect_size,(float)0.2); thrust::host_vector<float> vector3(vect_size,(float)0.2); start_t=clock(); thrust::transform(vector1.begin(),vector1.end(),vector2.begin(),vector3.begin(),thrust::multiplies<float>()); float sum=thrust::reduce(vector3.begin(),vector3.end(),(float)0,thrust::multiplies<float>()); end_t=clock();
向量相乘：0.187s
int vect_size=100000000; thrust::host_vector<float> vector1(vect_size,(float)0.1); thrust::host_vector<float> vector2(vect_size,(float)0.2); thrust::host_vector<float> vector3(vect_size); start_t=clock(); thrust::transform(vector1.begin(),vector1.end(),vector2.begin(),vector3.begin(),thrust::multiplies<float>()); end_t=clock();
矩阵乘向量：0.110s
struct matrixXvect_func
{
thrust::host_vector<float>* matrix;
thrust::host_vector<float>* vector;
int matrix_rownum;
int matrix_colnum;
__host__ __device__
float operator()(const int& idx) const{
float t=0;
for(int col=0;col<matrix_colnum;++col){
t+=(*matrix)[idx*matrix_colnum+col]* (*vector)[col];
}
return t;
}
};
int matrix1_colnum=50000;
int matrix1_size=matrix1_colnum*matrix1_rownum;
thrust::host_vector<float> vector1(matrix1_size,(float)0.1);
thrust::host_vector<float> vector2(matrix1_colnum,(float)0.2);
thrust::host_vector<float> vector3(matrix1_rownum);
start_t=clock();
matrixXvect_func fn;
fn.matrix=&vector1;
fn.vector=&vector2;
fn.matrix_rownum=matrix1_rownum;
fn.matrix_colnum=matrix1_colnum;
thrust::transform(
thrust::counting_iterator<int>(0),
thrust::counting_iterator<int>(0) + matrix1_rownum,
vector3.begin(),
fn
);
end_t=clock();
矩阵乘矩阵：0.655s
struct matrixXmatrix_func
{
thrust::host_vector<float>* matrix1;
thrust::host_vector<float>* matrix2;
int matrix1_rownum;
int matrix1_colnum;
int matrix2_rownum;
int matrix2_colnum;
__host__ __device__
float operator()(const int& idx) const{
int rownum=idx/matrix2_colnum;
int colnum=idx%matrix2_colnum;
float t=0;
for(int col=0;col<matrix1_colnum;++col){
t+=(*matrix1)[rownum*matrix1_colnum+col]* (*matrix2)[col*matrix2_colnum+colnum];
}
return t;
}
};
int matrix1_rownum=200;
int matrix1_colnum=5000;
int matrix1_size=matrix1_colnum*matrix1_rownum;
thrust::host_vector<float> vector1(matrix1_size,(float)0.1);
int matrix2_rownum=5000;
int matrix2_colnum=200;
int matrix2_size=matrix2_rownum*matrix2_colnum;
thrust::host_vector<float> vector2(matrix2_size,(float)0.2);
int matrix3_size=matrix1_rownum*matrix2_colnum;
thrust::host_vector<float> vector3(matrix3_size);
start_t=clock();
matrixXmatrix_func fn;
fn.matrix1=&vector1;
fn.matrix2=&vector2;
fn.matrix1_rownum=matrix1_rownum;
fn.matrix1_colnum=matrix1_colnum;
fn.matrix2_rownum=matrix2_rownum;
fn.matrix2_colnum=matrix2_colnum;
thrust::transform(
thrust::counting_iterator<int>(0),
thrust::counting_iterator<int>(0) + matrix3_size,
vector3.begin(),
fn
);
end_t=clock();
标签：style blog http ar os 使用 sp for strong
原文地址：http://www.cnblogs.com/plwang1990/p/4147379.html
