首先，命名规范：
There are three levels of BLAS operations,
-
Level 1
-
Vector operations, e.g.
y = /alpha x + y 向量操作
-
Level 2
-
Matrix-vector operations, e.g.
y = /alpha A x + /beta y 矩阵与向量操作
-
Level 3
-
Matrix-matrix operations, e.g.
C = /alpha A B + C 矩阵与矩阵的操作
Each routine has a name which specifies the operation, the type of matrices involved and their precisions. Some of the most common operations and their names are given below,
-
DOT
-
scalar product,
x^T y
-
AXPY
-
vector sum,
/alpha x + y
-
MV
-
matrix-vector product,
A x
-
SV
-
matrix-vector solve,
inv(A) x
-
MM
-
matrix-matrix product,
A B
-
SM
-
matrix-matrix solve,
inv(A) B
The type of matrices are,
-
GE
-
general
-
GB
-
general band
-
SY
-
symmetric
-
SB
-
symmetric band
-
SP
-
symmetric packed
-
HE
-
hermitian
-
HB
-
hermitian band
-
HP
-
hermitian packed
-
TR
-
triangular
-
TB
-
triangular band
-
TP
-
triangular packed
Each operation is defined for four precisions,
-
S
-
single real
-
D
-
double real
-
C
-
single complex
-
Z
-
double complex
Thus, for example, the name SGEMM stands for "single-precision general matrix-matrix multiply" and ZGEMM stands for "double-precision complex matrix-matrix multiply".
因此，例如，命名为SGEMM的函数意思为“单精度普通矩阵乘法”，ZGEMM为“双精度复数矩阵乘法”。
更多的，可以参考：http://www.netlib.org/blas/blasqr.pdf
下面这个例子是在csdn论坛上看到的，简单地改一下，可用GotoBlas2调用成功。
程序说明：下面的matrix.c 文件分别调用 C 代码， BLAS Level 1 函数 (ddot), BLAS Level 2 函数(dgemv) 与 BLAS Level 3的函数(DGEMM)完成矩阵计算： Yours_multiply 是 C 源代码，它直接依赖编译器生成优化代码。Ddot_Multiply，Dgemv_multiply使用Gotoblas2调用实现部分矩阵运算。Dgemm_multiply 直接调用GotoBlas2 的矩阵计算函数。
//Simple minded matrix multiply #include #include #include #include //GotoBlas2 #include //GotoBlas2 void print_arr(int N, char * name, double* array); void init_arr(int N, double* a); void Dgemm_multiply(double* a,double* b,double* c, int N); void Dgemv_multiply(double* a,double* b,double* c, int N); void Ddot_Multiply(double* a,double* b,double* c, int N); void Yours_multiply(double* a,double* b,double* c, int N); int main(int argc, char* argv[]) { clock_t start, stop; int i, j; int N; double* a; double* b; double* c; if(argc < 2) { printf("Enter matrix size N="); //please enter small number first to ensure that the //multiplication is correct! and then you may enter //a "reasonably" large number say like 500 or even 1000 scanf("%d",&N); } else { N = atoi(argv[1]); } a=(double*) malloc( sizeof(double)*N*N ); b=(double*) malloc( sizeof(double)*N*N ); c=(double*) malloc( sizeof(double)*N*N ); init_arr(N,a); init_arr(N,b); start = clock(); Yours_multiply(a,b,c,N); stop = clock(); printf("roll_your_own_multiply(). Elapsed time = %g seconds/n", ((double)(stop - start)) / CLOCKS_PER_SEC); //print simple test case of data to be sure multiplication is correct if (N < 7) { print_arr(N,"a", a); print_arr(N,"b", b); print_arr(N,"c", c); } free(a); free(b); free(c); //DDOT multiply a=(double*) malloc( sizeof(double)*N*N ); b=(double*) malloc( sizeof(double)*N*N ); c=(double*) malloc( sizeof(double)*N*N ); init_arr(N,a); init_arr(N,b); start = clock(); Ddot_Multiply(a,b,c,N); stop = clock(); printf("Ddot_Multiply(). Elapsed time = %g seconds/n", ((double)(stop - start)) / CLOCKS_PER_SEC); //print simple test case of data to be sure multiplication is correct if (N < 7) { print_arr(N,"a", a); print_arr(N,"b", b); print_arr(N,"c", c); } free(a); free(b); free(c); //DGEMV Multiply //reallcoate to force cash to be flushed a=(double*) malloc( sizeof(double)*N*N ); b=(double*) malloc( sizeof(double)*N*N ); c=(double*) malloc( sizeof(double)*N*N ); init_arr(N,a); init_arr(N,b); start = clock(); Dgemv_multiply(a,b,c,N); stop = clock(); printf("Dgemv_multiply(). Elapsed time = %g seconds/n", ((double)(stop - start)) / CLOCKS_PER_SEC); //print simple test case of data to be sure multiplication is correct if (N < 7) { print_arr(N,"a", a); print_arr(N,"b", b); print_arr(N,"c", c); } free(a); free(b); free(c); //DGEMM Multiply //reallocate to force cash to be flushed a=(double*) malloc( sizeof(double)*N*N ); b=(double*) malloc( sizeof(double)*N*N ); c=(double*) malloc( sizeof(double)*N*N ); init_arr(N,a); init_arr(N,b); start = clock(); Dgemm_multiply(a,b,c,N); stop = clock(); printf("Dgemm_multiply(). Elapsed time = %g seconds/n", ((double)(stop - start)) / CLOCKS_PER_SEC); //print simple test case of data to be sure multiplication is correct if (N < 7) { print_arr(N,"a", a); print_arr(N,"b", b); print_arr(N,"c", c); } free(a); free(b); free(c); return 0; } //Brute force way of matrix multiply void Yours_multiply(double* a,double* b,double* c, int N) { int i, j, k; for (i=0;i
