来自Cython的调用blaotDotot

我想从使用Cython的BLAS库使用点积，但是当调用编译模块时出现以下跟踪“未定义符号：cblas_ddot”。执行np。配置 .show（）来查看链接库：来自Cython的调用blaotDotot

lapack_info: 
     libraries = ['lapack', 'lapack'] 
     library_dirs = ['/usr/lib64'] 
     language = f77 

lapack_info: 
    libraries = ['lapack', 'lapack'] 
    library_dirs = ['/usr/lib64'] 
    language = f77 

openblas_lapack_info: 
    NOT AVAILABLE 

blas_info: 
    libraries = ['cblas', 'blas'] 
    library_dirs = ['/usr/lib64'] 
    define_macros = [('HAVE_CBLAS', None)] 
    language = c 

atlas_3_10_blas_threads_info: 
    NOT AVAILABLE 

atlas_threads_info: 
    NOT AVAILABLE 

atlas_3_10_threads_info: 
    NOT AVAILABLE 

atlas_blas_info: 
    NOT AVAILABLE 

atlas_3_10_blas_info: 
    NOT AVAILABLE 

atlas_blas_threads_info: 
    NOT AVAILABLE 

openblas_info: 
    NOT AVAILABLE 

blas_mkl_info: 
    NOT AVAILABLE 

blas_opt_info: 
    libraries = ['cblas', 'blas'] 
    library_dirs = ['/usr/lib64'] 
    language = c 
    define_macros = [('NO_ATLAS_INFO', 1), ('HAVE_CBLAS', None)] 

blis_info: 
    NOT AVAILABLE 

atlas_info: 
    NOT AVAILABLE 
atlas_3_10_info: 
    NOT AVAILABLE 

lapack_mkl_info: 
    NOT AVAILABLE

和LDD /usr/lib/python2.7/site-packages/numpy/core/multiarray.so和的readlink -e在/ usr/lib/libblas.so.3显示： /usr/lib/libblas.so.3.7.0

显然，BLAS库已链接，但未找到cblas_ddot。该PYX文件：

import numpy as np 
cimport numpy as np 

cdef extern from "cblas.h": 
    double ddot "cblas_ddot"(int N, 
          double *X, int incX, 
          double *Y, int incY) 

ctypedef np.float64_t dtype_t 
def matmul(np.ndarray[dtype_t, ndim=2] A, 
      np.ndarray[dtype_t, ndim=2] B): 
    cdef Py_ssize_t i, j 
    cdef np.ndarray[dtype_t,ndim=2] out = np.zeros((A.shape[0],B.shape[1])) 
    cdef np.ndarray[dtype_t, ndim=1] A_row, B_col 
    for i in range(A.shape[0]): 
     A_row = A[i,:] 
     for j in range(B.shape[1]): 
      B_col = B[:, j] 
      out[i,j] = ddot(
       A_row.shape[0], 
       <dtype_t*>A_row.data, 
       A_row.strides[0] // sizeof(dtype_t), 
       <dtype_t*>B_col.data, 
       B_col.strides[0] // sizeof(dtype_t))

的编译文件看起来像：进口numpy的

if __name__ == '__main__': 

    from distutils.core import setup 
    from distutils.extension import Extension 
    from Cython.Distutils import build_ext 


    # The Cython modules to setup 
    ext_modules = [ 
     Extension('matmul', ['matmul.pyx'], include_dirs= 
     [numpy.get_include()]) 
    ] 

    # Run the setup command 
    setup(
     cmdclass = {'build_ext': build_ext}, 
     ext_modules = ext_modules 
    )

来源

2017-05-30 Nayher Andres Clavijo Vallejo

你能展示你如何编译它吗？ – DavidW

是的，先生，帖子是用编译命令更新的 –

你只需要告诉它的图书馆在setup.py链接：

Extension(... # as before 
    libraries=[':libcblas.so.3'] 
)

确切的库可能取决于你已安装的内容。首先尝试'cblas'，如果失败，则查找您拥有的libcblas文件。请注意，您需要链接到libcblas而不是libblas。

你也可以查看Scipy BLAS Cython bindings节省你一些时间手动创建这些东西（虽然我认为这些是为BLAS而不是CBLAS）。

来源

2017-06-01 18:26:04 DavidW

来自Cython的调用blaotDotot

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