On Thu, Feb 12, 2015 at 3:00 PM, Neal Becker wrote:

Robert Kern wrote:

...

On Thu, Feb 12, 2015 at 2:21 PM, Neal Becker

...

...

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],

wrote: 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? -- Robert Kern

On Thu, Feb 12, 2015 at 3:22 PM, Neal Becker wrote:

Robert Kern wrote:

...

On Thu, Feb 12, 2015 at 3:00 PM, Neal Becker

wrote:

...

...

Robert Kern wrote:

...

On Thu, Feb 12, 2015 at 2:21 PM, Neal Becker

...

...

...

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],

wrote: 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

At 07:45 AM 2/12/2015, you wrote:

Robert Kern wrote:

...

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:

...

...

s='np.unpackbits(np.frombuffer(np.asarray(np.pi),

It's also fastest, with most pushed to numpy: dtype=np.uint8)).astype(np.int32)'

...

...

timr(s) 0.000252470827292 s="np.array([b for b in bin(struct.unpack('!i',struct.pack('!f',1.0))[0])[2:]], 'int32')" timr(s) 0.000513665240078 s="np.unpackbits (np.array (memoryview(struct.pack ('d', np.pi)))).astype(np.int32)" timr(s) 0.000466455247988 s="np.array([b for b in np.binary_repr(314159)], 'int32')" timr(s) 0.000423350472602

Hmmm np.unpackbits (np.array (memoryview(struct.pack ('d', np.pi)))).astype(np.int32) np.array([b for b in np.binary_repr(314159)], 'int32') # ints only! np.array([b for b in bin(struct.unpack('!i',struct.pack('!f',1.0))[0])[2:]], 'int32') timing is untested. - Ray Schumacher At 07:22 AM 2/12/2015, you wrote:

Robert Kern wrote:

...

On Thu, Feb 12, 2015 at 3:00 PM, Neal Becker wrote:

...

Robert Kern wrote:

...

On Thu, Feb 12, 2015 at 2:21 PM, Neal Becker

...

...

...

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],

wrote: 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.

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