Python numpy.frombuffer函数代码示例

def _read_dig_point_struct(fid, tag, shape, rlims):
    """Read dig point struct tag."""
    return dict(
        kind=int(np.frombuffer(fid.read(4), dtype=">i4")),
        ident=int(np.frombuffer(fid.read(4), dtype=">i4")),
        r=np.frombuffer(fid.read(12), dtype=">f4"),
        coord_frame=FIFF.FIFFV_COORD_UNKNOWN)

def eleventhPass(idxArray, ageArray, disPops, P_Age, length, name, myPipe):
	# collect sample stats
	subObs = {}
	subExp = {}
	sampleN = myPipe.recv()
	idxArray = np.frombuffer(idxArray.get_obj(), dtype=np.int32)
	ageArray = np.frombuffer(ageArray.get_obj(), dtype=np.int8)
	while sampleN != 'END':
		# sample = np.random.choice(idxArray, length, replace=True)
		randomIndexs = np.random.choice(xrange(idxArray.shape[0]), length, replace=True)
		sample = idxArray[randomIndexs]
		sampleAges = ageArray[randomIndexs]
		counts = Counter(sample)
		ageCounts = Counter(sampleAges)
		for i in xrange(len(disPops)):
			disPop = np.frombuffer(disPops[i].get_obj(), dtype=np.int32)
			P_Dis_Age = P_Age[i]
			obsSampled = set(disPop) & set(sample)
			expSampled = np.sum([P_Dis_Age[k] * v for k, v in ageCounts.iteritems()])
			try:
				subObs[i].append(sum([counts[s] for s in obsSampled])) 
				subExp[i].append(expSampled)
			except KeyError:
				subObs[i] = [sum([counts[s] for s in obsSampled])]
				subExp[i] = [expSampled]
		del sample
		if sampleN % 50 == 0:
			sys.stdout.write('.')
			sys.stdout.flush()
		sampleN = myPipe.recv()

	myPipe.send([subObs, subExp])
	# print len(subStats[0])
	return 0

def get_trace(f, num_points, big):
    """
    Get a trace from an open RNMRTK file.

    Parameters
    -----------
    f : file object
        Open file object to read from.
    num_points : int
        Number of points in trace (R+I)
    big : bool
        True for data that is big-endian, False for little-endian.

    Returns
    -------
    trace : ndarray
        Raw trace of NMR data.

    """
    if big:
        bsize = num_points * np.dtype('>f4').itemsize
        return np.frombuffer(f.read(bsize), dtype='>f4')
    else:
        bsize = num_points * np.dtype('<f4').itemsize
        return np.frombuffer(f.read(bsize), dtype='<f4')

 def test_create_with_metadata(self):
     for length in range(0, 1000, 3):
         # Create an object id string.
         object_id = random_object_id()
         # Create a random metadata string.
         metadata = generate_metadata(length)
         # Create a new buffer and write to it.
         memory_buffer = np.frombuffer(self.plasma_client.create(object_id,
                                                                 length,
                                                                 metadata),
                                       dtype="uint8")
         for i in range(length):
             memory_buffer[i] = i % 256
         # Seal the object.
         self.plasma_client.seal(object_id)
         # Get the object.
         memory_buffer = np.frombuffer(
             self.plasma_client.get_buffers([object_id])[0], dtype="uint8")
         for i in range(length):
             assert memory_buffer[i] == i % 256
         # Get the metadata.
         metadata_buffer = np.frombuffer(
             self.plasma_client.get_metadata([object_id])[0], dtype="uint8")
         assert len(metadata) == len(metadata_buffer)
         for i in range(len(metadata)):
             assert metadata[i] == metadata_buffer[i]

    def prepare_np_frame(self, shape_str, buf_str):
        '''
        Convert raw frame buffer to numpy array and apply warp perspective
        transformation.

        Emits:

            frame-update : New numpy video frame available with perspective
                transform applied.
        '''
        height, width, channels = np.frombuffer(shape_str, count=3,
                                                dtype='uint32')
        im_buf = np.frombuffer(buf_str, dtype='uint8',
                               count=len(buf_str)).reshape(height, width, -1)

        # Warp and scale
        if self.frame_shape != (width, height):
            # Frame shape has changed.
            old_frame_shape = self.frame_shape
            self.frame_shape = width, height
            self.emit('frame-shape-changed', old_frame_shape, self.frame_shape)
            if self.shape is None:
                self.shape = width, height
        np_warped = cv2.warpPerspective(im_buf, self.transform, self.shape)
        self.emit('frame-update', np_warped)

    def v2_apply_symmetry(self, symmetry, content):
        """
            Apply a random symmetry to a v2 record.
        """
        assert symmetry >= 0 and symmetry < 8

        # unpack the record.
        (ver, probs, planes, to_move, winner) = self.v2_struct.unpack(content)

        planes = np.unpackbits(np.frombuffer(planes, dtype=np.uint8))
        # We use the full length reflection tables to apply symmetry
        # to all 16 planes simultaneously
        planes = planes[self.full_reflection_table[symmetry]]
        assert len(planes) == 19*19*16
        planes = np.packbits(planes)
        planes = planes.tobytes()

        probs = np.frombuffer(probs, dtype=np.float32)
        # Apply symmetries to the probabilities.
        probs = probs[self.prob_reflection_table[symmetry]]
        assert len(probs) == 362
        probs = probs.tobytes()

        # repack record.
        return self.v2_struct.pack(ver, probs, planes, to_move, winner)

 def _read_data(self, fh, byteorder='>'):
     """Return image data from open file as numpy array."""
     fh.seek(len(self.header))
     data = fh.read()
     dtype = 'u1' if self.maxval < 256 else byteorder + 'u2'
     depth = 1 if self.magicnum == b"P7 332" else self.depth
     shape = [-1, self.height, self.width, depth]
     size = functools.reduce(operator.mul, shape[1:], 1)  # prod()
     if self.magicnum in b"P1P2P3":
         data = numpy.array(data.split(None, size)[:size], dtype)
         data = data.reshape(shape)
     elif self.maxval == 1:
         shape[2] = int(math.ceil(self.width / 8))
         data = numpy.frombuffer(data, dtype).reshape(shape)
         data = numpy.unpackbits(data, axis=-2)[:, :, :self.width, :]
     else:
         size *= numpy.dtype(dtype).itemsize
         data = numpy.frombuffer(data[:size], dtype).reshape(shape)
     if data.shape[0] < 2:
         data = data.reshape(data.shape[1:])
     if data.shape[-1] < 2:
         data = data.reshape(data.shape[:-1])
     if self.magicnum == b"P7 332":
         rgb332 = numpy.array(list(numpy.ndindex(8, 8, 4)), numpy.uint8)
         rgb332 *= [36, 36, 85]
         data = numpy.take(rgb332, data, axis=0)
     return data

    def create_vectors(self, verbs):
        """Create vectors with simple frequency."""
        self.logger.info('Creating frequency vectors for %d features with '
                         '%s...', len(self.feats), verbs)

        j_indices = array.array(str('i'))
        indptr = array.array(str('i'))
        indptr.append(0)
        values = array.array(str('i'))

        for verb in verbs:
            verb_ngrams = verb.ngrams()
            for ngram in verb_ngrams:
                try:
                    j_indices.append(self.feats[ngram])
                except KeyError:
                    pass
                else:
                    values.append(verb_ngrams[ngram])
            indptr.append(len(j_indices))

        j_indices = np.frombuffer(j_indices, dtype=np.intc)
        indptr = np.frombuffer(indptr, dtype=np.intc)
        values = np.frombuffer(values, dtype=np.intc)

        dtm = sparse.csr_matrix((values, j_indices, indptr),
                                shape=(len(indptr) - 1, len(self.feats)))

        dtm.sum_duplicates()

        if self.should_normalize:
            normalize(dtm)

        return dtm

 def get_cbs(self, gene_id, cb_type):
     if cb_type == 'ub':
         return numpy.frombuffer(self.ubs[gene_id])
     elif cb_type == 'lb':
         return numpy.frombuffer(self.lbs[gene_id])
     else: 
         assert False, "Unrecognized confidence bound type '%s'" % cb_type

def load_data():
    """Loads the Fashion-MNIST dataset.
    # Returns
        Tuple of Numpy arrays: `(x_train, y_train), (x_test, y_test)`.
    """
    dirname = os.path.join('datasets', 'fashion-mnist')
    base = 'http://fashion-mnist.s3-website.eu-central-1.amazonaws.com/'
    files = ['train-labels-idx1-ubyte.gz', 'train-images-idx3-ubyte.gz',
             't10k-labels-idx1-ubyte.gz', 't10k-images-idx3-ubyte.gz']

    paths = []
    for file in files:
        paths.append(get_file(file, origin=base + file, cache_subdir=dirname))

    with gzip.open(paths[0], 'rb') as lbpath:
        y_train = np.frombuffer(lbpath.read(), np.uint8, offset=8)

    with gzip.open(paths[1], 'rb') as imgpath:
        x_train = np.frombuffer(imgpath.read(), np.uint8,
                                offset=16).reshape(len(y_train), 28, 28)

    with gzip.open(paths[2], 'rb') as lbpath:
        y_test = np.frombuffer(lbpath.read(), np.uint8, offset=8)

    with gzip.open(paths[3], 'rb') as imgpath:
        x_test = np.frombuffer(imgpath.read(), np.uint8,
                               offset=16).reshape(len(y_test), 28, 28)

    return (x_train, y_train), (x_test, y_test)

    def micro_step(self, adve=True, cond=True):
        """ Defining microphysical step """
        libopts = libcl.lgrngn.opts_t()
        libopts.cond = cond
        libopts.adve = adve
        libopts.coal = libopts.sedi = False

        self.micro.step_sync(libopts, self.state_micro["th_d"], self.state_micro["rv"], self.state_micro["rho_d"])
        self.micro.step_async(libopts)
        
        # absolute number of super-droplets per grid cell
        self.micro.diag_sd_conc()
        self.state_micro["sd"][:] = np.frombuffer(self.micro.outbuf())
        
        # number of particles (per kg of dry air) with r_w < .5 um
        self.micro.diag_wet_rng(0, .5e-6)
        self.micro.diag_wet_mom(0)
        self.state_micro["na"][:] = np.frombuffer(self.micro.outbuf())
        
        # number of particles (per kg of dry air) with r_w > .5 um
        self.micro.diag_wet_rng(.5e-6, 1)
        self.micro.diag_wet_mom(0)
        self.state_micro["nc"][:] = np.frombuffer(self.micro.outbuf())
        
        # cloud water mixing ratio [kg/kg] (same size threshold as above)
        self.micro.diag_wet_mom(3)
        rho_H2O = 1e3
        self.state_micro["rc"][:] = 4./3 * math.pi * rho_H2O * np.frombuffer(self.micro.outbuf())

def bits_float(BYTES):
    d0 = np.frombuffer(BYTES[0::3], dtype='u1').astype(float)
    d1 = np.frombuffer(BYTES[1::3], dtype='u1').astype(float)
    d2 = np.frombuffer(BYTES[2::3], dtype='i1').astype(float)
    d0 += 256 * d1
    d0 += 65536 * d2
    return d0

    def _term_counts_to_matrix(self, n_doc, i_indices, j_indices, values):
        """Construct COO matrix from indices and values.

        i_indices and j_indices should be constructed with _make_int_array.
        """
        # array("i") corresponds to np.intc, which is also what scipy.sparse
        # wants for indices, so they won't be copied by the coo_matrix ctor.
        # The length check works around a bug in old NumPy versions:
        # http://projects.scipy.org/numpy/ticket/1943
        if len(i_indices) > 0:
            i_indices = np.frombuffer(i_indices, dtype=np.intc)
        if len(j_indices) > 0:
            j_indices = np.frombuffer(j_indices, dtype=np.intc)

        if self.dtype == np.intc and len(values) > 0:
            values = np.frombuffer(values, dtype=np.intc)
        else:
            # In Python 3.2, SciPy 0.10.1, the coo_matrix ctor won't accept an
            # array.array.
            values = np.asarray(values, dtype=self.dtype)

        shape = (n_doc, max(six.itervalues(self.vocabulary_)) + 1)
        spmatrix = sp.coo_matrix((values, (i_indices, j_indices)),
                                 shape=shape, dtype=self.dtype)
        if self.binary:
            spmatrix.data.fill(1)
        return spmatrix

    def _get_data(self):
        if self._train:
            data, label = self._train_data, self._train_label
        else:
            data, label = self._test_data, self._test_label

        namespace = 'gluon/dataset/'+self._namespace
        data_file = download(_get_repo_file_url(namespace, data[0]),
                             path=self._root,
                             sha1_hash=data[1])
        label_file = download(_get_repo_file_url(namespace, label[0]),
                              path=self._root,
                              sha1_hash=label[1])

        with gzip.open(label_file, 'rb') as fin:
            struct.unpack(">II", fin.read(8))
            label = np.frombuffer(fin.read(), dtype=np.uint8).astype(np.int32)

        with gzip.open(data_file, 'rb') as fin:
            struct.unpack(">IIII", fin.read(16))
            data = np.frombuffer(fin.read(), dtype=np.uint8)
            data = data.reshape(len(label), 28, 28, 1)

        self._data = nd.array(data, dtype=data.dtype)
        self._label = label

    def plotdata(self, offset, nsamples=spksamples):
        f = self.datafile
        f.seek(offset*nchannels*4)
        data = np.frombuffer(f.read(4*nsamples*nchannels), dtype=np.float32)
        nsamples = len(data) // nchannels

        t = np.arange(offset, offset+nsamples)/samplingrate
        axis = [t.min(), t.max(), -maxamp, maxamp]
        
        for p in self.p:
            if p: p.remove()
        for p in self.spk:
            p.remove()
        
        for i in xrange(nchannels):
            ax = self.ax[i]
            self.p[i], = ax.plot(t, data[i::nchannels], 'k-',
                                 scalex=False, scaley=False)
            ax.axis(axis)
            
        f = self.validationdata
        f.seek(offset*4)
        data = np.frombuffer(f.read(4*nsamples), dtype=np.float32)
        data = np.convolve(self.filt, data)[self.filti:-self.filtj]
        ax = self.ax[nchannels]
        self.p[nchannels], = ax.plot(t, data, 'k-',
                                 scalex=False, scaley=False)
        ax.axis([t.min(), t.max(), -self.validationamp, self.validationamp])
            
        return nsamples