Python numpy.iinfo() Examples

def reduce_id_bits(segmentation):
  """Reduces the number of bits used for IDs.

  Assumes that one additional ID beyond the max of 'segmentation' is necessary
  (used by GALA to mark boundary areas).

  Args:
    segmentation: ndarray of int type

  Returns:
    segmentation ndarray converted to minimal uint type large enough to keep
    all the IDs.
  """
  max_id = segmentation.max()
  if max_id <= np.iinfo(np.uint8).max:
    return segmentation.astype(np.uint8)
  elif max_id <= np.iinfo(np.uint16).max:
    return segmentation.astype(np.uint16)
  elif max_id <= np.iinfo(np.uint32).max:
    return segmentation.astype(np.uint32) 

def fit(self, X, y):
        if X.shape[0] == 0:
            return self
        elif np.unique(y).shape[0] <= 1:
            self.update_aux(y)
            return self

        seed = self.random_state.integers(np.iinfo(np.int32).max)
        self.model.set_params(random_state = seed)
        self.model.fit(X, y)
        n_nodes = self.model.tree_.node_count
        self.pos = np.zeros(n_nodes, dtype=ctypes.c_long)
        self.neg = np.zeros(n_nodes, dtype=ctypes.c_long)
        pred_node = self.model.apply(X).astype(ctypes.c_long)
        _create_node_counters(self.pos, self.neg, pred_node, y.astype(ctypes.c_double))
        self.pos = self.pos.astype(ctypes.c_double) + self.beta_prior[0]
        self.neg = self.neg.astype(ctypes.c_double) + self.beta_prior[1]

        self.is_fitted = True
        return self 

def hparams(self, defaults, model_hparams):
    p = model_hparams
    # Filterbank extraction in bottom instead of preprocess_example is faster.
    p.add_hparam("audio_preproc_in_bottom", False)
    # The trainer seems to reserve memory for all members of the input dict
    p.add_hparam("audio_keep_example_waveforms", False)
    p.add_hparam("audio_sample_rate", 16000)
    p.add_hparam("audio_preemphasis", 0.97)
    p.add_hparam("audio_dither", 1.0 / np.iinfo(np.int16).max)
    p.add_hparam("audio_frame_length", 25.0)
    p.add_hparam("audio_frame_step", 10.0)
    p.add_hparam("audio_lower_edge_hertz", 20.0)
    p.add_hparam("audio_upper_edge_hertz", 8000.0)
    p.add_hparam("audio_num_mel_bins", 80)
    p.add_hparam("audio_add_delta_deltas", True)
    p.add_hparam("num_zeropad_frames", 250)

    p = defaults
    # p.stop_at_eos = int(False)
    p.input_modality = {"inputs": ("audio:speech_recognition_modality", None)}
    p.target_modality = (registry.Modalities.SYMBOL, 256) 

def _do_scaling(self):
        arr = self._array
        out_dtype = self._out_dtype
        assert out_dtype.kind in 'iu'
        mn, mx = self.finite_range()
        if arr.dtype.kind == 'f':
            # Float to (u)int scaling
            self._range_scale()
            return
        # (u)int to (u)int
        info = np.iinfo(out_dtype)
        out_max, out_min = info.max, info.min
        # If left as int64, uint64, comparisons will default to floats, and
        # these are inexact for > 2**53 - so convert to int
        if (as_int(mx) <= as_int(out_max) and
            as_int(mn) >= as_int(out_min)):
            # already in range
            return
        # (u)int to (u)int scaling
        self._iu2iu() 

def _get_valid_range(self):
        ''' Return valid range for image data

        The valid range can come from the image 'valid_range' or
        image 'valid_min' and 'valid_max', or, failing that, from the
        data type range
        '''
        ddt = self.get_data_dtype()
        info = np.iinfo(ddt.type)
        try:
            valid_range = self._image.valid_range
        except AttributeError:
            try:
                valid_range = [self._image.valid_min,
                               self._image.valid_max]
            except AttributeError:
                valid_range = [info.min, info.max]
        if valid_range[0] < info.min or valid_range[1] > info.max:
            raise ValueError('Valid range outside input '
                             'data type range')
        return np.asarray(valid_range, dtype=np.float) 

def test_int_int_min_max():
    # Conversion between (u)int and (u)int
    eps = np.finfo(np.float64).eps
    rtol = 1e-6
    for in_dt in IUINT_TYPES:
        iinf = np.iinfo(in_dt)
        arr = np.array([iinf.min, iinf.max], dtype=in_dt)
        for out_dt in IUINT_TYPES:
            try:
                aw = SlopeInterArrayWriter(arr, out_dt)
            except ScalingError:
                continue
            arr_back_sc = round_trip(aw)
            # integer allclose
            adiff = int_abs(arr - arr_back_sc)
            rdiff = adiff / (arr + eps)
            assert_true(np.all(rdiff < rtol)) 

def test_int_int_slope():
    # Conversion between (u)int and (u)int for slopes only
    eps = np.finfo(np.float64).eps
    rtol = 1e-7
    for in_dt in IUINT_TYPES:
        iinf = np.iinfo(in_dt)
        for out_dt in IUINT_TYPES:
            kinds = np.dtype(in_dt).kind + np.dtype(out_dt).kind
            if kinds in ('ii', 'uu', 'ui'):
                arrs = (np.array([iinf.min, iinf.max], dtype=in_dt),)
            elif kinds == 'iu':
                arrs = (np.array([iinf.min, 0], dtype=in_dt),
                        np.array([0, iinf.max], dtype=in_dt))
            for arr in arrs:
                try:
                    aw = SlopeArrayWriter(arr, out_dt)
                except ScalingError:
                    continue
                assert_false(aw.slope == 0)
                arr_back_sc = round_trip(aw)
                # integer allclose
                adiff = int_abs(arr - arr_back_sc)
                rdiff = adiff / (arr + eps)
                assert_true(np.all(rdiff < rtol)) 

def test_able_casting():
    # Check the able_int_type function guesses numpy out type
    types = np.sctypes['int'] + np.sctypes['uint']
    for in_type in types:
        in_info = np.iinfo(in_type)
        in_mn, in_mx = in_info.min, in_info.max
        A = np.zeros((1,), dtype=in_type)
        for out_type in types:
            out_info = np.iinfo(out_type)
            out_mn, out_mx = out_info.min, out_info.max
            B = np.zeros((1,), dtype=out_type)
            ApBt = (A + B).dtype.type
            able_type = able_int_type([in_mn, in_mx, out_mn, out_mx])
            if able_type is None:
                assert_equal(ApBt, np.float64)
                continue
            # Use str for comparison to avoid int32/64 vs intp comparison
            # failures
            assert_equal(np.dtype(ApBt).str, np.dtype(able_type).str) 

def _uniform_weight_alpha(sum_masked_arrays, output_datatype):
    '''Calculates the cumulative mask of a list of masked array

    Input:
        sum_masked_arrays (list of numpy masked arrays): The list of
            masked arrays to find the cumulative mask of, each element
            represents one band.
            (sums_masked_array.mask has a 1 for a no data pixel and
            a 0 otherwise)
        output_datatype (numpy datatype): The output datatype

    Output:
        output_alpha (numpy uint16 array): The output mask
            (0 for a no data pixel, uint16 max value otherwise)
    '''

    output_alpha = numpy.ones(sum_masked_arrays[0].shape)
    for band_sum_masked_array in sum_masked_arrays:
        output_alpha[numpy.nonzero(band_sum_masked_array.mask == 1)] = 0

    output_alpha = output_alpha.astype(output_datatype) * \
        numpy.iinfo(output_datatype).max

    return output_alpha 

def test_big_indices(self):
        # ravel_multi_index for big indices (issue #7546)
        if np.intp == np.int64:
            arr = ([1, 29], [3, 5], [3, 117], [19, 2],
                   [2379, 1284], [2, 2], [0, 1])
            assert_equal(
                np.ravel_multi_index(arr, (41, 7, 120, 36, 2706, 8, 6)),
                [5627771580, 117259570957])

        # test overflow checking for too big array (issue #7546)
        dummy_arr = ([0],[0])
        half_max = np.iinfo(np.intp).max // 2
        assert_equal(
            np.ravel_multi_index(dummy_arr, (half_max, 2)), [0])
        assert_raises(ValueError,
            np.ravel_multi_index, dummy_arr, (half_max+1, 2))
        assert_equal(
            np.ravel_multi_index(dummy_arr, (half_max, 2), order='F'), [0])
        assert_raises(ValueError,
            np.ravel_multi_index, dummy_arr, (half_max+1, 2), order='F') 

def test_allclose(self):
        # Tests allclose on arrays
        a = np.random.rand(10)
        b = a + np.random.rand(10) * 1e-8
        assert_(allclose(a, b))
        # Test allclose w/ infs
        a[0] = np.inf
        assert_(not allclose(a, b))
        b[0] = np.inf
        assert_(allclose(a, b))
        # Test allclose w/ masked
        a = masked_array(a)
        a[-1] = masked
        assert_(allclose(a, b, masked_equal=True))
        assert_(not allclose(a, b, masked_equal=False))
        # Test comparison w/ scalar
        a *= 1e-8
        a[0] = 0
        assert_(allclose(a, 0, masked_equal=True))

        # Test that the function works for MIN_INT integer typed arrays
        a = masked_array([np.iinfo(np.int_).min], dtype=np.int_)
        assert_(allclose(a, a)) 

def test_respect_dtype_singleton(self):
        # See gh-7203
        for dt in self.itype:
            lbnd = 0 if dt is np.bool_ else np.iinfo(dt).min
            ubnd = 2 if dt is np.bool_ else np.iinfo(dt).max + 1

            sample = self.rfunc(lbnd, ubnd, dtype=dt)
            assert_equal(sample.dtype, np.dtype(dt))

        for dt in (bool, int, np.long):
            lbnd = 0 if dt is bool else np.iinfo(dt).min
            ubnd = 2 if dt is bool else np.iinfo(dt).max + 1

            # gh-7284: Ensure that we get Python data types
            sample = self.rfunc(lbnd, ubnd, dtype=dt)
            assert_(not hasattr(sample, 'dtype'))
            assert_equal(type(sample), dt) 

def test_can_cast_values(self):
        # gh-5917
        for dt in np.sctypes['int'] + np.sctypes['uint']:
            ii = np.iinfo(dt)
            assert_(np.can_cast(ii.min, dt))
            assert_(np.can_cast(ii.max, dt))
            assert_(not np.can_cast(ii.min - 1, dt))
            assert_(not np.can_cast(ii.max + 1, dt))

        for dt in np.sctypes['float']:
            fi = np.finfo(dt)
            assert_(np.can_cast(fi.min, dt))
            assert_(np.can_cast(fi.max, dt))


# Custom exception class to test exception propagation in fromiter 

def _linear_transformation_to_lut(linear_transformation,
                                  max_value=None, dtype=numpy.uint16):
    min_value = 0
    if max_value is None:
        max_value = numpy.iinfo(dtype).max

    def gain_offset_to_lut(gain, offset):
        logging.debug(
            'Normalize: Calculating lut values for gain '
            '{} and offset {}'.format(gain, offset))
        lut = numpy.arange(min_value, max_value + 1, dtype=numpy.float)
        return gain * lut + offset

    lut = gain_offset_to_lut(linear_transformation.gain,
                             linear_transformation.offset)

    logging.debug('Normalize: Clipping lut from [{}, {}] to [{},{}]'.format(
        min(lut), max(lut), min_value, max_value))
    numpy.clip(lut, min_value, max_value, lut)

    return lut.astype(dtype) 

def argmin(self, axis=None, skipna=True, *args, **kwargs):
        """
        Returns the indices of the minimum values along an axis.

        See `numpy.ndarray.argmin` for more information on the
        `axis` parameter.

        See Also
        --------
        numpy.ndarray.argmin
        """
        nv.validate_argmin(args, kwargs)
        nv.validate_minmax_axis(axis)

        i8 = self.asi8
        if self.hasnans:
            mask = self._isnan
            if mask.all() or not skipna:
                return -1
            i8 = i8.copy()
            i8[mask] = np.iinfo('int64').max
        return i8.argmin() 

def _parallel_predict(self, contexts: np.ndarray, is_predict: bool):

        # Total number of contexts to predict
        n_contexts = len(contexts)

        # Partition contexts by job
        n_jobs, n_contexts, starts = self._partition_contexts(n_contexts)
        total_contexts = sum(n_contexts)

        # Get seed value for each context
        seeds = self.rng.randint(np.iinfo(np.int32).max, size=total_contexts)

        # Perform parallel predictions
        predictions = Parallel(n_jobs=n_jobs, backend=self.backend)(
                          delayed(self._predict_contexts)(
                              contexts[starts[i]:starts[i + 1]],
                              is_predict,
                              seeds[starts[i]:starts[i + 1]],
                              starts[i])
                          for i in range(n_jobs))

        # Reduce
        predictions = list(chain.from_iterable(t for t in predictions))

        return predictions if len(predictions) > 1 else predictions[0] 

def test_constructor_overflow_int64(self):
        # see gh-15832
        msg = ("The elements provided in the data cannot "
               "all be casted to the dtype int64")
        with pytest.raises(OverflowError, match=msg):
            Index([np.iinfo(np.uint64).max - 1], dtype="int64") 

def test_basic(self):
        dts = list(zip(['i1', 'i2', 'i4', 'i8',
                   'u1', 'u2', 'u4', 'u8'],
                  [np.int8, np.int16, np.int32, np.int64,
                   np.uint8, np.uint16, np.uint32, np.uint64]))
        for dt1, dt2 in dts:
            for attr in ('bits', 'min', 'max'):
                assert_equal(getattr(iinfo(dt1), attr),
                             getattr(iinfo(dt2), attr), attr)
        assert_raises(ValueError, iinfo, 'f4') 

def test_shape_invalid(self):
        # Check that the shape is valid.
        max_int = np.iinfo(np.intc).max
        max_intp = np.iinfo(np.intp).max
        # Too large values (the datatype is part of this)
        assert_raises(ValueError, np.dtype, [('a', 'f4', max_int // 4 + 1)])
        assert_raises(ValueError, np.dtype, [('a', 'f4', max_int + 1)])
        assert_raises(ValueError, np.dtype, [('a', 'f4', (max_int, 2))])
        # Takes a different code path (fails earlier:
        assert_raises(ValueError, np.dtype, [('a', 'f4', max_intp + 1)])
        # Negative values
        assert_raises(ValueError, np.dtype, [('a', 'f4', -1)])
        assert_raises(ValueError, np.dtype, [('a', 'f4', (-1, -1))]) 

def test_min_int(self):
        # Could make problems because of abs(min_int) == min_int
        min_int = np.iinfo(np.int_).min
        a = np.array([min_int], dtype=np.int_)
        assert_(np.allclose(a, a)) 

def test_implementation_limits(self):
        min_td = Timedelta(Timedelta.min)
        max_td = Timedelta(Timedelta.max)

        # GH 12727
        # timedelta limits correspond to int64 boundaries
        assert min_td.value == np.iinfo(np.int64).min + 1
        assert max_td.value == np.iinfo(np.int64).max

        # Beyond lower limit, a NAT before the Overflow
        assert (min_td - Timedelta(1, 'ns')) is NaT

        with pytest.raises(OverflowError):
            min_td - Timedelta(2, 'ns')

        with pytest.raises(OverflowError):
            max_td + Timedelta(1, 'ns')

        # Same tests using the internal nanosecond values
        td = Timedelta(min_td.value - 1, 'ns')
        assert td is NaT

        with pytest.raises(OverflowError):
            Timedelta(min_td.value - 2, 'ns')

        with pytest.raises(OverflowError):
            Timedelta(max_td.value + 1, 'ns') 

def test_min_int(self):
        a = np.array([np.iinfo(np.int_).min], dtype=np.int_)
        # Should not raise:
        assert_allclose(a, a) 

def test_poisson_exceptions(self):
        lambig = np.iinfo('l').max
        lamneg = -1
        assert_raises(ValueError, np.random.poisson, lamneg)
        assert_raises(ValueError, np.random.poisson, [lamneg]*10)
        assert_raises(ValueError, np.random.poisson, lambig)
        assert_raises(ValueError, np.random.poisson, [lambig]*10) 

def test_random_integers_deprecated(self):
        with warnings.catch_warnings():
            warnings.simplefilter("error", DeprecationWarning)

            # DeprecationWarning raised with high == None
            assert_raises(DeprecationWarning,
                          np.random.random_integers,
                          np.iinfo('l').max)

            # DeprecationWarning raised with high != None
            assert_raises(DeprecationWarning,
                          np.random.random_integers,
                          np.iinfo('l').max, np.iinfo('l').max) 

def test_random_integers_max_int(self):
        # Tests whether random_integers can generate the
        # maximum allowed Python int that can be converted
        # into a C long. Previous implementations of this
        # method have thrown an OverflowError when attempting
        # to generate this integer.
        with suppress_warnings() as sup:
            w = sup.record(DeprecationWarning)
            actual = np.random.random_integers(np.iinfo('l').max,
                                               np.iinfo('l').max)
            assert_(len(w) == 1)

        desired = np.iinfo('l').max
        assert_equal(actual, desired) 

def encode(self, s):
    """Transform a string with a filename into a list of float32.

    Args:
      s: path to the file with a waveform.

    Returns:
      samples: list of int16s
    """
    # Make sure that the data is a single channel, 16bit, 16kHz wave.
    # TODO(chorowski): the directory may not be writable, this should fallback
    # to a temp path, and provide instructions for installing sox.
    if s.endswith(".mp3"):
      # TODO(dliebling) On Linux, check if libsox-fmt-mp3 is installed.
      out_filepath = s[:-4] + ".wav"
      call([
          "sox", "--guard", s, "-r", "16k", "-b", "16", "-c", "1", out_filepath
      ])
      s = out_filepath
    elif not s.endswith(".wav"):
      out_filepath = s + ".wav"
      if not os.path.exists(out_filepath):
        call(["sox", "-r", "16k", "-b", "16", "-c", "1", s, out_filepath])
      s = out_filepath
    rate, data = wavfile.read(s)
    assert rate == self._sample_rate
    assert len(data.shape) == 1
    if data.dtype not in [np.float32, np.float64]:
      data = data.astype(np.float32) / np.iinfo(data.dtype).max
    return data.tolist() 

def test_full_range(self):
        # Test for ticket #1690

        for dt in self.itype:
            lbnd = 0 if dt is np.bool_ else np.iinfo(dt).min
            ubnd = 2 if dt is np.bool_ else np.iinfo(dt).max + 1

            try:
                self.rfunc(lbnd, ubnd, dtype=dt)
            except Exception as e:
                raise AssertionError("No error should have been raised, "
                                     "but one was with the following "
                                     "message:\n\n%s" % str(e)) 

def test_rng_zero_and_extremes(self):
        for dt in self.itype:
            lbnd = 0 if dt is np.bool_ else np.iinfo(dt).min
            ubnd = 2 if dt is np.bool_ else np.iinfo(dt).max + 1

            tgt = ubnd - 1
            assert_equal(self.rfunc(tgt, tgt + 1, size=1000, dtype=dt), tgt)

            tgt = lbnd
            assert_equal(self.rfunc(tgt, tgt + 1, size=1000, dtype=dt), tgt)

            tgt = (lbnd + ubnd)//2
            assert_equal(self.rfunc(tgt, tgt + 1, size=1000, dtype=dt), tgt) 

def test_bounds_checking(self):
        for dt in self.itype:
            lbnd = 0 if dt is np.bool_ else np.iinfo(dt).min
            ubnd = 2 if dt is np.bool_ else np.iinfo(dt).max + 1
            assert_raises(ValueError, self.rfunc, lbnd - 1, ubnd, dtype=dt)
            assert_raises(ValueError, self.rfunc, lbnd, ubnd + 1, dtype=dt)
            assert_raises(ValueError, self.rfunc, ubnd, lbnd, dtype=dt)
            assert_raises(ValueError, self.rfunc, 1, 0, dtype=dt) 

def test_instances():
    iinfo(10)
    finfo(3.0)