Robert Kern wrote:
> On Thu, Feb 12, 2015 at 3:22 PM, Neal Becker <ndbeck...@gmail.com> wrote:
>>
>> Robert Kern wrote:
>>
>> > On Thu, Feb 12, 2015 at 3:00 PM, Neal Becker <ndbeck...@gmail.com>
> wrote:
>> >>
>> >> Robert Kern wrote:
>> >>
>> >> > On Thu, Feb 12, 2015 at 2:21 PM, Neal Becker <ndbeck...@gmail.com>
>> > wrote:
>> >> >>
>> >> >> I need to transmit some data values. These values will be float and
>> > long
>> >> >> values. I need them encoded into a string of bits.
>> >> >>
>> >> >> The only way I found so far to do this seems rather roundabout:
>> >> >>
>> >> >>
>> >> >> np.unpackbits (np.array (memoryview(struct.pack ('d', pi))))
>> >> >> Out[45]:
>> >> >> array([0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0,
> 0,
>> > 1,
>> >> > 0,
>> >> >> 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0, 1,
> 0,
>> > 0,
>> >> > 0,
>> >> >> 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0],
>> > dtype=uint8)
>> >> >>
>> >> >> (which I'm not certain is correct)
>> >> >>
>> >> >> Also, I don't know how to reverse this process
>> >> >
>> >> > You already had your string ready for transmission with
>> > `struct.pack('d',
>> >> > pi)`.
>> >> >
>> >> > --
>> >> > Robert Kern
>> >>
>> >> my transmitter wants an np array of bits, not a string
>> >
>> > Can you provide any details on what your "transmitter" is?
>> >
>> > --
>>
>> My transmitter is c++ code that accepts as input a numpy array of
> np.int32.
>> Each element of that array has value 0 or 1.
>
> Ah, great. That makes sense, then.
>
> def tobeckerbits(x):
> return np.unpackbits(np.frombuffer(np.asarray(x),
> dtype=np.uint8)).astype(np.int32)
>
> def frombeckerbits(bits, dtype):
> return np.frombuffer(np.packbits(bits), dtype=dtype)[0]
>
> --
> Robert Kern
Nice! Also seems to work for arrays of values:
def tobeckerbits(x):
return np.unpackbits(np.frombuffer(np.asarray(x),
dtype=np.uint8)).astype(np.int32)
def frombeckerbits(bits, dtype):
return np.frombuffer(np.packbits(bits), dtype=dtype) << leaving off the [0]
x = tobeckerbits (2.7)
y = frombeckerbits (x, float)
x2 = tobeckerbits (np.array ((1.1, 2.2)))
y2 = frombeckerbits (x2, float)
--
-- Those who don't understand recursion are doomed to repeat it
_______________________________________________
NumPy-Discussion mailing list
NumPy-Discussion@scipy.org
http://mail.scipy.org/mailman/listinfo/numpy-discussion
