Error while trying to write a simple example using Numba

[Veeresh Taranalli]

Hi

I am trying to write a simple example using Numba as follows

==============================================================

from numba import d, i

from numba.decorators import jit as jit

import numpy as np

def viterbi_decode(coded_bits, k, n, total_memory):

    rate = k/n

    return rate

viterbi_decode_numba = jit(ret_type=d, arg_types=[d[:], d, d, i])(viterbi_decode)

cbits = np.array([1,0,1,1,0,1,1], dtype=float)

k = 1

n = 3

total_memory = 6

rate = viterbi_decode_numba(cbits, k, n, total_memory)

print rate

===============================================================

The error i get is as follows:

===============================================================

Traceback (most recent call last):

  File "viterbi_numba.py", line 14, in <module>

    viterbi_decode_numba = jit(ret_type=d, arg_types=[d[:], d, d, i])(viterbi_decode)

  File "/usr/local/lib/python2.7/dist-packages/numba/decorators.py", line 81, in _jit

    return t.get_ctypes_func(llvm)

  File "/usr/local/lib/python2.7/dist-packages/numba/translate.py", line 1145, in get_ctypes_func

    for x in self.arg_types])

  File "/usr/local/lib/python2.7/dist-packages/numba/translate.py", line 377, in convert_to_ctypes

    dtype_str = np.dtype(typ).str

TypeError: data type not understood

================================================================

However this error goes away if i pass the last argument 'total_memory' as a double, i.e., d instead of i in the arg_types list.

Any ideas if I am doing something the wrong way?

Thanks,

Veeresh Taranalli

[Jon Riehl]

This is a bug in how the numba.i type gets translated to another
internal type language. The work around is to use the (soon to be
deprecated) string type declaration for your integer types.

So try (notice the quotes around the i in arg_types):

viterbi_decode_numba = jit(ret_type=d, arg_types=[d[:], d, d,
'i'])(viterbi_decode)

This should work until we get a fix.

Thanks,
-Jon

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