在numpy中使用mkl_set_num_threads [英] Using mkl_set_num_threads with numpy

问题描述

我正在尝试使用mkl_set_num_threads这样设置numpy计算的线程数

I'm trying to set the number of threads for numpy calculations with mkl_set_num_threads like this

import numpy
import ctypes
mkl_rt = ctypes.CDLL('libmkl_rt.so')
mkl_rt.mkl_set_num_threads(4)

但我不断遇到细分错误:

but I keep getting an segmentation fault:

Program received signal SIGSEGV, Segmentation fault.
0x00002aaab34d7561 in mkl_set_num_threads__ () from /../libmkl_intel_lp64.so

获取线程数没问题:

print mkl_rt.mkl_get_max_threads()

如何使我的代码正常工作? 还是有另一种方法可以在运行时设置线程数?

How can I get my code working? Or is there another way to set the number of threads at runtime?

推荐答案

Ophion引导了我正确的方法.尽管有文档说明，但必须通过引用来传递mkl_set_num_thread的参数.

Ophion led me the right way. Despite the documentation, one have to transfer the parameter of mkl_set_num_thread by reference.

现在我已经定义了用于获取和设置线程的函数

Now I have defined to functions, for getting and setting the threads

import numpy
import ctypes
mkl_rt = ctypes.CDLL('libmkl_rt.so')
mkl_get_max_threads = mkl_rt.mkl_get_max_threads
def mkl_set_num_threads(cores):
    mkl_rt.mkl_set_num_threads(ctypes.byref(ctypes.c_int(cores)))

mkl_set_num_threads(4)
print mkl_get_max_threads() # says 4

它们按预期工作.

根据Rufflewind的说法，C函数的名称以大写形式编写，期望按值使用参数:

according to Rufflewind, the names of the C-Functions are written in capital-case, which expect parameters by value:

import ctypes

mkl_rt = ctypes.CDLL('libmkl_rt.so')
mkl_set_num_threads = mkl_rt.MKL_Set_Num_Threads
mkl_get_max_threads = mkl_rt.MKL_Get_Max_Threads

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