我试图用Cython的prange
来提高一些度量计算的性能。这是我的代码:Cython的prange没有提高性能
def shausdorff(float64_t[:,::1] XA not None, float64_t[:,:,::1] XB not None):
cdef:
Py_ssize_t i
Py_ssize_t n = XB.shape[2]
float64_t[::1] hdist = np.zeros(n)
#arrangement to fix contiguity
XB = np.asanyarray([np.ascontiguousarray(XB[:,:,i]) for i in range(n)])
for i in range(n):
hdist[i] = _hausdorff(XA, XB[i])
return hdist
def phausdorff(float64_t[:,::1] XA not None, float64_t[:,:,::1] XB not None):
cdef:
Py_ssize_t i
Py_ssize_t n = XB.shape[2]
float64_t[::1] hdist = np.zeros(n)
#arrangement to fix contiguity (EDITED)
cdef float64_t[:,:,::1] XC = np.asanyarray([np.ascontiguousarray(XB[:,:,i]) for i in range(n)])
with nogil, parallel(num_threads=4):
for i in prange(n, schedule='static', chunksize=1):
hdist[i] = _hausdorff(XA, XC[i])
return hdist
基本上,在每次迭代中Hausdorff度量计算XA
并且每个XB[i]
之间。这里是_hausdorff
函数的签名:
cdef inline float64_t _hausdorff(float64_t[:,::1] XA, float64_t[:,::1] XB) nogil:
...
我的问题是,无论是连续shausdorff
和并行phausdorff
具有相同的时序。此外,看起来phausdorff
根本没有创建任何线程。
所以我的问题是我的代码有什么问题,我该如何解决它以获得线程工作。
这是我的setup.py
:
from distutils.core import setup
from distutils.extension import Extension
from Cython.Build import cythonize
from Cython.Distutils import build_ext
ext_modules=[
Extension("custom_metric",
["custom_metric.pyx"],
libraries=["m"],
extra_compile_args = ["-O3", "-ffast-math", "-march=native", "-fopenmp" ],
extra_link_args=['-fopenmp']
)
]
setup(
name = "custom_metric",
cmdclass = {"build_ext": build_ext},
ext_modules = ext_modules
)
EDIT 1:下面是由cython -a
生成的HTML的链接:custom_metric.html
编辑2:下面是如何调用的示例相应的功能(需要先编译the Cython file)
import custom_metric as cm
import numpy as np
XA = np.random.random((9000, 210))
XB = np.random.random((1000, 210, 9))
#timing 'parallel' version
%timeit cm.phausdorff(XA, XB)
#timing sequential version
%timeit cm.shausdorff(XA, XB)
您是否尝试在'prange'的循环体内将等价物打印到'omp_get_thread_num()'。请参阅http://cython.readthedocs.io/en/latest/src/userguide/parallelism.html – Harald
可能是'XB'是一个Python对象?用注释运行'cython -a custom_metric.pyx'。 – cgohlke
如果用'@ cython.boundscheck(False)'和'@ cython.wraparound(False)'装饰'phausdorff',是否有任何更改? –