numpy/core/tests/test_getlimits.py

""" Test functions for limits module.

"""
from __future__ import division, absolute_import, print_function

import numpy as np
from numpy.core import finfo, iinfo
from numpy import half, single, double, longdouble
from numpy.testing import (
    run_module_suite, assert_equal, assert_, assert_raises
)
from numpy.core.getlimits import (_discovered_machar, _float16_ma, _float32_ma,
                                  _float64_ma, _float128_ma, _float80_ma)

##################################################

class TestPythonFloat(object):
    def test_singleton(self):
        ftype = finfo(float)
        ftype2 = finfo(float)
        assert_equal(id(ftype), id(ftype2))

class TestHalf(object):
    def test_singleton(self):
        ftype = finfo(half)
        ftype2 = finfo(half)
        assert_equal(id(ftype), id(ftype2))

class TestSingle(object):
    def test_singleton(self):
        ftype = finfo(single)
        ftype2 = finfo(single)
        assert_equal(id(ftype), id(ftype2))

class TestDouble(object):
    def test_singleton(self):
        ftype = finfo(double)
        ftype2 = finfo(double)
        assert_equal(id(ftype), id(ftype2))

class TestLongdouble(object):
    def test_singleton(self):
        ftype = finfo(longdouble)
        ftype2 = finfo(longdouble)
        assert_equal(id(ftype), id(ftype2))

class TestFinfo(object):
    def test_basic(self):
        dts = list(zip(['f2', 'f4', 'f8', 'c8', 'c16'],
                       [np.float16, np.float32, np.float64, np.complex64,
                        np.complex128]))
        for dt1, dt2 in dts:
            for attr in ('bits', 'eps', 'epsneg', 'iexp', 'machar', 'machep',
                         'max', 'maxexp', 'min', 'minexp', 'negep', 'nexp',
                         'nmant', 'precision', 'resolution', 'tiny'):
                assert_equal(getattr(finfo(dt1), attr),
                             getattr(finfo(dt2), attr), attr)
        assert_raises(ValueError, finfo, 'i4')

class TestIinfo(object):
    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_unsigned_max(self):
        types = np.sctypes['uint']
        for T in types:
            assert_equal(iinfo(T).max, T(-1))

class TestRepr(object):
    def test_iinfo_repr(self):
        expected = "iinfo(min=-32768, max=32767, dtype=int16)"
        assert_equal(repr(np.iinfo(np.int16)), expected)

    def test_finfo_repr(self):
        expected = "finfo(resolution=1e-06, min=-3.4028235e+38," + \
                   " max=3.4028235e+38, dtype=float32)"
        assert_equal(repr(np.finfo(np.float32)), expected)


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


def assert_ma_equal(discovered, ma_like):
    # Check MachAr-like objects same as calculated MachAr instances
    for key, value in discovered.__dict__.items():
        assert_equal(value, getattr(ma_like, key))
        if hasattr(value, 'shape'):
            assert_equal(value.shape, getattr(ma_like, key).shape)
            assert_equal(value.dtype, getattr(ma_like, key).dtype)


def test_known_types():
    # Test we are correctly compiling parameters for known types
    for ftype, ma_like in ((np.float16, _float16_ma),
                           (np.float32, _float32_ma),
                           (np.float64, _float64_ma)):
        assert_ma_equal(_discovered_machar(ftype), ma_like)
    # Suppress warning for broken discovery of double double on PPC
    with np.errstate(all='ignore'):
        ld_ma = _discovered_machar(np.longdouble)
    bytes = np.dtype(np.longdouble).itemsize
    if (ld_ma.it, ld_ma.maxexp) == (63, 16384) and bytes in (12, 16):
        # 80-bit extended precision
        assert_ma_equal(ld_ma, _float80_ma)
    elif (ld_ma.it, ld_ma.maxexp) == (112, 16384) and bytes == 16:
        # IEE 754 128-bit
        assert_ma_equal(ld_ma, _float128_ma)


def test_plausible_finfo():
    # Assert that finfo returns reasonable results for all types
    for ftype in np.sctypes['float'] + np.sctypes['complex']:
        info = np.finfo(ftype)
        assert_(info.nmant > 1)
        assert_(info.minexp < -1)
        assert_(info.maxexp > 1)


if __name__ == "__main__":
    run_module_suite()