Error during data passing in cluster. TypeError: Read-only buffer does not support the buffer interface about ipyparallel

[tlikhomanenko]

Problem with numpy arrays:

x.map_sync(test_client, [range(10000)]) 

works fine.

[tlikhomanenko]

numpy.__config__.show()

>> lapack_info:
  NOT AVAILABLE
lapack_opt_info:
  NOT AVAILABLE
openblas_lapack_info:
  NOT AVAILABLE
blas_info:
    libraries = ['blas']
    library_dirs = ['/usr/lib']
    language = f77
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
lapack_src_info:
  NOT AVAILABLE
atlas_blas_threads_info:
  NOT AVAILABLE
openblas_info:
  NOT AVAILABLE
blas_mkl_info:
  NOT AVAILABLE
blas_opt_info:
    libraries = ['blas']
    library_dirs = ['/usr/lib']
    language = f77
    define_macros = [('NO_ATLAS_INFO', 1)]
atlas_info:
  NOT AVAILABLE
atlas_3_10_info:
  NOT AVAILABLE
lapack_mkl_info:
  NOT AVAILABLE
mkl_info:
  NOT AVAILABLE

[dhirschfeld]

The array is writeable? Maybe try explicitly setting the flag, or if it is writeable setting it inside the test_client function or both (just guessing here)

In [1]: x = np.ones(1000)

In [2]: x.flags
Out[2]: 
  C_CONTIGUOUS : True
  F_CONTIGUOUS : True
  OWNDATA : True
  WRITEABLE : True
  ALIGNED : True
  UPDATEIFCOPY : False

In [3]: x.flags['WRITEABLE'] = True

In [4]: def test_client(x):
   ...:     x.flags['WRITEABLE'] = True
   ...:     return x

[minrk]

When pyzmq provides a buffer owned by zeromq, which happens for the zero-copy recv on the engine, it is flagged as read-only.

[tlikhomanenko]

The problem in memoryview which is used during sending data to client. This is an error of python 2.7.3

import numpy
x  = numpy.arange(10000)
memoryview(buffer(a.data)
>>
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-23-1db7db8f2911> in <module>()
----> 1 memoryview(buffer(a.data))

TypeError: cannot make memory view because object does not have the buffer interface

[minrk]

Hm, I'm having some trouble reproducing this. Does it work if you get more recent pyzmq and/or ipyparallel, both of which have had releases since the version you list?

[tlikhomanenko]

I reinstalled ipyparallel == 4.0.0 (pyzmq 15.0.0), the same error. After installation pyzmq 14.7.0 the error is the same. With pyzmq==14.4.0/14.5.0/14.6.0 it works!