numpy-discussion

[Numpy-discussion] Grief with a complex value

[Colin J. W. <cj...@sy...>]

 >>> import numpy.core as _n
 >>> _nt= _n.numerictypes
 >>> value= 
'\x00\x00\x00\x00\x00\x00\xf0?\x00\x00\x00\x00\x00\x00\x00@\x00\x00\x00\x00\x00\x00\x08@\x00\x00\x00\x00\x00\x00\x10@\x00\x00\x00\x00\x00\x00\x14@\x00\x00\x00\x00\x00\x00\x18@'
 >>> _n.array(value, dtype= _nt.complex128, copy=True)
Traceback (most recent call last):
  File "<interactive input>", line 1, in <module>
TypeError: a float is required
 >>>

A bug?

Colin W.

Re: [Numpy-discussion] Grief with a complex value

[Robert K. <rob...@gm...>]

Colin J. Williams wrote:
>  >>> import numpy.core as _n
>  >>> _nt= _n.numerictypes
>  >>> value= 
> '\x00\x00\x00\x00\x00\x00\xf0?\x00\x00\x00\x00\x00\x00\x00@\x00\x00\x00\x00\x00\x00\x08@\x00\x00\x00\x00\x00\x00\x10@\x00\x00\x00\x00\x00\x00\x14@\x00\x00\x00\x00\x00\x00\x18@'
>  >>> _n.array(value, dtype= _nt.complex128, copy=True)
> Traceback (most recent call last):
>   File "<interactive input>", line 1, in <module>
> TypeError: a float is required
>  >>>
> 
> A bug?

No. array() takes sequences, not data buffers. You want frombuffer().

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

Re: [Numpy-discussion] Grief with a complex value

[Colin J. W. <cj...@sy...>]

Robert Kern wrote:
> Colin J. Williams wrote:
>   
>>  >>> import numpy.core as _n
>>  >>> _nt= _n.numerictypes
>>  >>> value= 
>> '\x00\x00\x00\x00\x00\x00\xf0?\x00\x00\x00\x00\x00\x00\x00@\x00\x00\x00\x00\x00\x00\x08@\x00\x00\x00\x00\x00\x00\x10@\x00\x00\x00\x00\x00\x00\x14@\x00\x00\x00\x00\x00\x00\x18@'
>>  >>> _n.array(value, dtype= _nt.complex128, copy=True)
>> Traceback (most recent call last):
>>   File "<interactive input>", line 1, in <module>
>> TypeError: a float is required
>>  >>>
>>
>> A bug?
>>     
>
> No. array() takes sequences, not data buffers. You want frombuffer().
>   
Thanks.

Colin W.

Re: [Numpy-discussion] Grief with a complex value

[Stefan v. d. W. <st...@su...>]

On Thu, Nov 09, 2006 at 03:18:57AM -0500, Colin J. Williams wrote:
>=20
>  >>> import numpy.core as _n
>  >>> _nt=3D _n.numerictypes
>  >>> value=3D=20
> '\x00\x00\x00\x00\x00\x00\xf0?\x00\x00\x00\x00\x00\x00\x00@\x00\x00\x00=
\x00\x00\x00\x08@\x00\x00\x00\x00\x00\x00\x10@\x00\x00\x00\x00\x00\x00\x1=
4@\x00\x00\x00\x00\x00\x00\x18@'
>  >>> _n.array(value, dtype=3D _nt.complex128, copy=3DTrue)
> Traceback (most recent call last):
>   File "<interactive input>", line 1, in <module>
> TypeError: a float is required
>  >>>

If I understand correctly, you would like to create an array from a
buffer:

In [12]: N.frombuffer(value,dtype=3DN.complex128)
Out[12]: array([ 1.+2.j,  3.+4.j,  5.+6.j])

Cheers
St=E9fan

Re: [Numpy-discussion] Grief with a complex value

[Colin J. W. <cj...@sy...>]

Stefan van der Walt wrote:
> On Thu, Nov 09, 2006 at 03:18:57AM -0500, Colin J. Williams wrote:
>   
>>  >>> import numpy.core as _n
>>  >>> _nt= _n.numerictypes
>>  >>> value= 
>> '\x00\x00\x00\x00\x00\x00\xf0?\x00\x00\x00\x00\x00\x00\x00@\x00\x00\x00\x00\x00\x00\x08@\x00\x00\x00\x00\x00\x00\x10@\x00\x00\x00\x00\x00\x00\x14@\x00\x00\x00\x00\x00\x00\x18@'
>>  >>> _n.array(value, dtype= _nt.complex128, copy=True)
>> Traceback (most recent call last):
>>   File "<interactive input>", line 1, in <module>
>> TypeError: a float is required
>>  >>>
>>     
>
> If I understand correctly, you would like to create an array from a
> buffer:
>
> In [12]: N.frombuffer(value,dtype=N.complex128)
> Out[12]: array([ 1.+2.j,  3.+4.j,  5.+6.j])
>
> Cheers
> Stéfan
>   
Thanks, I didn't find "frombuffer" in the Numpy Examples List. 

Incidentally, the List is a big help but it would be even better if it 
included the signatures of the functions.

Colin W.
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