Blas库使用说明

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”。

关于blas的具体介绍请参考：http://www.netlib.org/blas/

下面是一些具体的函数说明：

参考：http://blog.csdn.net/g_spider/article/details/6054990

Blas库使用说明

cblas使用：

extern "C" {
#include <common.h>
#include <cblas.h>
}


int main(void) {

    const enum CBLAS_ORDER Order=CblasRowMajor;
    const enum CBLAS_TRANSPOSE TransA=CblasTrans;
    const enum CBLAS_TRANSPOSE TransB=CblasNoTrans;

    const int M=1;//A的行数，C的行数 
    const int N=2;//B的列数，C的列数
    const int K=3;//A的列数，B的行数
    const double alpha=1;
    const double beta=0;

    const int lda=M;//A的列
    const int ldb=N;//B的列
    const int ldc=N;//C的列

    double A[]={ 1,2,3};

    double B[]={ 5,4,3,2,1,0};

    double C[2];

    cblas_dgemm(Order, TransA, TransB, M, N, K, alpha, A, lda, B, ldb, beta, C, ldc);

    for(int i=0;i<1;i++)
    {
       for(int j=0;j<2;j++)
       {
           cout<<C[i*2+j]<<" ";
       }
       cout<<endl;
    }

    return 0;
}

当使用转置时，M，N，K分别对应转置之后A,B,C的行、列，lda,ldb,ldc对应转置之前A,B,C的列

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Blas库使用说明

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