from __future__ import division, absolute_import, print_function

import sys

import numpy as np
from numpy.testing import *
import numpy.core.umath_tests as umt
import numpy.core.operand_flag_tests as opflag_tests
from numpy.compat import asbytes
from numpy.core.test_rational import *

class TestUfunc(TestCase):
    def test_pickle(self):
        import pickle
        assert pickle.loads(pickle.dumps(np.sin)) is np.sin

    def test_pickle_withstring(self):
        import pickle
        astring = asbytes("cnumpy.core\n_ufunc_reconstruct\np0\n"
                "(S'numpy.core.umath'\np1\nS'cos'\np2\ntp3\nRp4\n.")
        assert pickle.loads(astring) is np.cos

    def test_reduceat_shifting_sum(self) :
        L = 6
        x = np.arange(L)
        idx = np.array(list(zip(np.arange(L - 2), np.arange(L - 2) + 2))).ravel()
        assert_array_equal(np.add.reduceat(x, idx)[::2], [1, 3, 5, 7])

    def test_generic_loops(self) :
        """Test generic loops.

        The loops to be tested are:

            PyUFunc_ff_f_As_dd_d
            PyUFunc_ff_f
            PyUFunc_dd_d
            PyUFunc_gg_g
            PyUFunc_FF_F_As_DD_D
            PyUFunc_DD_D
            PyUFunc_FF_F
            PyUFunc_GG_G
            PyUFunc_OO_O
            PyUFunc_OO_O_method
            PyUFunc_f_f_As_d_d
            PyUFunc_d_d
            PyUFunc_f_f
            PyUFunc_g_g
            PyUFunc_F_F_As_D_D
            PyUFunc_F_F
            PyUFunc_D_D
            PyUFunc_G_G
            PyUFunc_O_O
            PyUFunc_O_O_method
            PyUFunc_On_Om

        Where:

            f -- float
            d -- double
            g -- long double
            F -- complex float
            D -- complex double
            G -- complex long double
            O -- python object

        It is difficult to assure that each of these loops is entered from the
        Python level as the special cased loops are a moving target and the
        corresponding types are architecture dependent. We probably need to
        define C level testing ufuncs to get at them. For the time being, I've
        just looked at the signatures registered in the build directory to find
        relevant functions.

        Fixme, currently untested:

            PyUFunc_ff_f_As_dd_d
            PyUFunc_FF_F_As_DD_D
            PyUFunc_f_f_As_d_d
            PyUFunc_F_F_As_D_D
            PyUFunc_On_Om

        """
        fone = np.exp
        ftwo = lambda x, y : x**y
        fone_val = 1
        ftwo_val = 1
        # check unary PyUFunc_f_f.
        msg = "PyUFunc_f_f"
        x = np.zeros(10, dtype=np.single)[0::2]
        assert_almost_equal(fone(x), fone_val, err_msg=msg)
        # check unary PyUFunc_d_d.
        msg = "PyUFunc_d_d"
        x = np.zeros(10, dtype=np.double)[0::2]
        assert_almost_equal(fone(x), fone_val, err_msg=msg)
        # check unary PyUFunc_g_g.
        msg = "PyUFunc_g_g"
        x = np.zeros(10, dtype=np.longdouble)[0::2]
        assert_almost_equal(fone(x), fone_val, err_msg=msg)
        # check unary PyUFunc_F_F.
        msg = "PyUFunc_F_F"
        x = np.zeros(10, dtype=np.csingle)[0::2]
        assert_almost_equal(fone(x), fone_val, err_msg=msg)
        # check unary PyUFunc_D_D.
        msg = "PyUFunc_D_D"
        x = np.zeros(10, dtype=np.cdouble)[0::2]
        assert_almost_equal(fone(x), fone_val, err_msg=msg)
        # check unary PyUFunc_G_G.
        msg = "PyUFunc_G_G"
        x = np.zeros(10, dtype=np.clongdouble)[0::2]
        assert_almost_equal(fone(x), fone_val, err_msg=msg)

        # check binary PyUFunc_ff_f.
        msg = "PyUFunc_ff_f"
        x = np.ones(10, dtype=np.single)[0::2]
        assert_almost_equal(ftwo(x, x), ftwo_val, err_msg=msg)
        # check binary PyUFunc_dd_d.
        msg = "PyUFunc_dd_d"
        x = np.ones(10, dtype=np.double)[0::2]
        assert_almost_equal(ftwo(x, x), ftwo_val, err_msg=msg)
        # check binary PyUFunc_gg_g.
        msg = "PyUFunc_gg_g"
        x = np.ones(10, dtype=np.longdouble)[0::2]
        assert_almost_equal(ftwo(x, x), ftwo_val, err_msg=msg)
        # check binary PyUFunc_FF_F.
        msg = "PyUFunc_FF_F"
        x = np.ones(10, dtype=np.csingle)[0::2]
        assert_almost_equal(ftwo(x, x), ftwo_val, err_msg=msg)
        # check binary PyUFunc_DD_D.
        msg = "PyUFunc_DD_D"
        x = np.ones(10, dtype=np.cdouble)[0::2]
        assert_almost_equal(ftwo(x, x), ftwo_val, err_msg=msg)
        # check binary PyUFunc_GG_G.
        msg = "PyUFunc_GG_G"
        x = np.ones(10, dtype=np.clongdouble)[0::2]
        assert_almost_equal(ftwo(x, x), ftwo_val, err_msg=msg)

        # class to use in testing object method loops
        class foo(object):
            def conjugate(self) :
                return np.bool_(1)
            def logical_xor(self, obj) :
                return np.bool_(1)

        # check unary PyUFunc_O_O
        msg = "PyUFunc_O_O"
        x = np.ones(10, dtype=np.object)[0::2]
        assert_(np.all(np.abs(x) == 1), msg)
        # check unary PyUFunc_O_O_method
        msg = "PyUFunc_O_O_method"
        x = np.zeros(10, dtype=np.object)[0::2]
        for i in range(len(x)) :
            x[i] = foo()
        assert_(np.all(np.conjugate(x) == True), msg)

        # check binary PyUFunc_OO_O
        msg = "PyUFunc_OO_O"
        x = np.ones(10, dtype=np.object)[0::2]
        assert_(np.all(np.add(x, x) == 2), msg)
        # check binary PyUFunc_OO_O_method
        msg = "PyUFunc_OO_O_method"
        x = np.zeros(10, dtype=np.object)[0::2]
        for i in range(len(x)) :
            x[i] = foo()
        assert_(np.all(np.logical_xor(x, x)), msg)

        # check PyUFunc_On_Om
        # fixme -- I don't know how to do this yet

    def test_all_ufunc(self) :
        """Try to check presence and results of all ufuncs.

        The list of ufuncs comes from generate_umath.py and is as follows:

        =====  ====  =============  ===============  ========================
        done   args   function        types                notes
        =====  ====  =============  ===============  ========================
        n      1     conjugate      nums + O
        n      1     absolute       nums + O         complex -> real
        n      1     negative       nums + O
        n      1     sign           nums + O         -> int
        n      1     invert         bool + ints + O  flts raise an error
        n      1     degrees        real + M         cmplx raise an error
        n      1     radians        real + M         cmplx raise an error
        n      1     arccos         flts + M
        n      1     arccosh        flts + M
        n      1     arcsin         flts + M
        n      1     arcsinh        flts + M
        n      1     arctan         flts + M
        n      1     arctanh        flts + M
        n      1     cos            flts + M
        n      1     sin            flts + M
        n      1     tan            flts + M
        n      1     cosh           flts + M
        n      1     sinh           flts + M
        n      1     tanh           flts + M
        n      1     exp            flts + M
        n      1     expm1          flts + M
        n      1     log            flts + M
        n      1     log10          flts + M
        n      1     log1p          flts + M
        n      1     sqrt           flts + M         real x < 0 raises error
        n      1     ceil           real + M
        n      1     trunc          real + M
        n      1     floor          real + M
        n      1     fabs           real + M
        n      1     rint           flts + M
        n      1     isnan          flts             -> bool
        n      1     isinf          flts             -> bool
        n      1     isfinite       flts             -> bool
        n      1     signbit        real             -> bool
        n      1     modf           real             -> (frac, int)
        n      1     logical_not    bool + nums + M  -> bool
        n      2     left_shift     ints + O         flts raise an error
        n      2     right_shift    ints + O         flts raise an error
        n      2     add            bool + nums + O  boolean + is ||
        n      2     subtract       bool + nums + O  boolean - is ^
        n      2     multiply       bool + nums + O  boolean * is &
        n      2     divide         nums + O
        n      2     floor_divide   nums + O
        n      2     true_divide    nums + O         bBhH -> f, iIlLqQ -> d
        n      2     fmod           nums + M
        n      2     power          nums + O
        n      2     greater        bool + nums + O  -> bool
        n      2     greater_equal  bool + nums + O  -> bool
        n      2     less           bool + nums + O  -> bool
        n      2     less_equal     bool + nums + O  -> bool
        n      2     equal          bool + nums + O  -> bool
        n      2     not_equal      bool + nums + O  -> bool
        n      2     logical_and    bool + nums + M  -> bool
        n      2     logical_or     bool + nums + M  -> bool
        n      2     logical_xor    bool + nums + M  -> bool
        n      2     maximum        bool + nums + O
        n      2     minimum        bool + nums + O
        n      2     bitwise_and    bool + ints + O  flts raise an error
        n      2     bitwise_or     bool + ints + O  flts raise an error
        n      2     bitwise_xor    bool + ints + O  flts raise an error
        n      2     arctan2        real + M
        n      2     remainder      ints + real + O
        n      2     hypot          real + M
        =====  ====  =============  ===============  ========================

        Types other than those listed will be accepted, but they are cast to
        the smallest compatible type for which the function is defined. The
        casting rules are:

        bool -> int8 -> float32
        ints -> double

        """
        pass


    def test_signature(self):
        # the arguments to test_signature are: nin, nout, core_signature
        # pass
        assert_equal(umt.test_signature(2, 1, "(i),(i)->()"), 1)

        # pass. empty core signature; treat as plain ufunc (with trivial core)
        assert_equal(umt.test_signature(2, 1, "(),()->()"), 0)

        # in the following calls, a ValueError should be raised because
        # of error in core signature
        # error: extra parenthesis
        msg = "core_sig: extra parenthesis"
        try:
            ret = umt.test_signature(2, 1, "((i)),(i)->()")
            assert_equal(ret, None, err_msg=msg)
        except ValueError: None
        # error: parenthesis matching
        msg = "core_sig: parenthesis matching"
        try:
            ret = umt.test_signature(2, 1, "(i),)i(->()")
            assert_equal(ret, None, err_msg=msg)
        except ValueError: None
        # error: incomplete signature. letters outside of parenthesis are ignored
        msg = "core_sig: incomplete signature"
        try:
            ret = umt.test_signature(2, 1, "(i),->()")
            assert_equal(ret, None, err_msg=msg)
        except ValueError: None
        # error: incomplete signature. 2 output arguments are specified
        msg = "core_sig: incomplete signature"
        try:
            ret = umt.test_signature(2, 2, "(i),(i)->()")
            assert_equal(ret, None, err_msg=msg)
        except ValueError: None

        # more complicated names for variables
        assert_equal(umt.test_signature(2, 1, "(i1,i2),(J_1)->(_kAB)"), 1)

    def test_get_signature(self):
        assert_equal(umt.inner1d.signature, "(i),(i)->()")

    def test_forced_sig(self):
        a = 0.5*np.arange(3, dtype='f8')
        assert_equal(np.add(a, 0.5), [0.5, 1, 1.5])
        assert_equal(np.add(a, 0.5, sig='i', casting='unsafe'), [0, 0, 1])
        assert_equal(np.add(a, 0.5, sig='ii->i', casting='unsafe'), [0, 0, 1])
        assert_equal(np.add(a, 0.5, sig=('i4',), casting='unsafe'), [0, 0, 1])
        assert_equal(np.add(a, 0.5, sig=('i4', 'i4', 'i4'),
                                            casting='unsafe'), [0, 0, 1])

        b = np.zeros((3,), dtype='f8')
        np.add(a, 0.5, out=b)
        assert_equal(b, [0.5, 1, 1.5])
        b[:] = 0
        np.add(a, 0.5, sig='i', out=b, casting='unsafe')
        assert_equal(b, [0, 0, 1])
        b[:] = 0
        np.add(a, 0.5, sig='ii->i', out=b, casting='unsafe')
        assert_equal(b, [0, 0, 1])
        b[:] = 0
        np.add(a, 0.5, sig=('i4',), out=b, casting='unsafe')
        assert_equal(b, [0, 0, 1])
        b[:] = 0
        np.add(a, 0.5, sig=('i4', 'i4', 'i4'), out=b, casting='unsafe')
        assert_equal(b, [0, 0, 1])


    def test_inner1d(self):
        a = np.arange(6).reshape((2, 3))
        assert_array_equal(umt.inner1d(a, a), np.sum(a*a, axis=-1))
        a = np.arange(6)
        assert_array_equal(umt.inner1d(a, a), np.sum(a*a))

    def test_broadcast(self):
        msg = "broadcast"
        a = np.arange(4).reshape((2, 1, 2))
        b = np.arange(4).reshape((1, 2, 2))
        assert_array_equal(umt.inner1d(a, b), np.sum(a*b, axis=-1), err_msg=msg)
        msg = "extend & broadcast loop dimensions"
        b = np.arange(4).reshape((2, 2))
        assert_array_equal(umt.inner1d(a, b), np.sum(a*b, axis=-1), err_msg=msg)
        msg = "broadcast in core dimensions"
        a = np.arange(8).reshape((4, 2))
        b = np.arange(4).reshape((4, 1))
        assert_array_equal(umt.inner1d(a, b), np.sum(a*b, axis=-1), err_msg=msg)
        msg = "extend & broadcast core and loop dimensions"
        a = np.arange(8).reshape((4, 2))
        b = np.array(7)
        assert_array_equal(umt.inner1d(a, b), np.sum(a*b, axis=-1), err_msg=msg)
        msg = "broadcast should fail"
        a = np.arange(2).reshape((2, 1, 1))
        b = np.arange(3).reshape((3, 1, 1))
        try:
            ret = umt.inner1d(a, b)
            assert_equal(ret, None, err_msg=msg)
        except ValueError: None

    def test_type_cast(self):
        msg = "type cast"
        a = np.arange(6, dtype='short').reshape((2, 3))
        assert_array_equal(umt.inner1d(a, a), np.sum(a*a, axis=-1), err_msg=msg)
        msg = "type cast on one argument"
        a = np.arange(6).reshape((2, 3))
        b = a+0.1
        assert_array_almost_equal(umt.inner1d(a, a), np.sum(a*a, axis=-1),
            err_msg=msg)

    def test_endian(self):
        msg = "big endian"
        a = np.arange(6, dtype='>i4').reshape((2, 3))
        assert_array_equal(umt.inner1d(a, a), np.sum(a*a, axis=-1), err_msg=msg)
        msg = "little endian"
        a = np.arange(6, dtype='<i4').reshape((2, 3))
        assert_array_equal(umt.inner1d(a, a), np.sum(a*a, axis=-1), err_msg=msg)

        # Output should always be native-endian
        Ba = np.arange(1, dtype='>f8')
        La = np.arange(1, dtype='<f8')
        assert_equal((Ba+Ba).dtype, np.dtype('f8'))
        assert_equal((Ba+La).dtype, np.dtype('f8'))
        assert_equal((La+Ba).dtype, np.dtype('f8'))
        assert_equal((La+La).dtype, np.dtype('f8'))

        assert_equal(np.absolute(La).dtype, np.dtype('f8'))
        assert_equal(np.absolute(Ba).dtype, np.dtype('f8'))
        assert_equal(np.negative(La).dtype, np.dtype('f8'))
        assert_equal(np.negative(Ba).dtype, np.dtype('f8'))

    def test_incontiguous_array(self):
        msg = "incontiguous memory layout of array"
        x = np.arange(64).reshape((2, 2, 2, 2, 2, 2))
        a = x[:, 0,:, 0,:, 0]
        b = x[:, 1,:, 1,:, 1]
        a[0, 0, 0] = -1
        msg2 = "make sure it references to the original array"
        assert_equal(x[0, 0, 0, 0, 0, 0], -1, err_msg=msg2)
        assert_array_equal(umt.inner1d(a, b), np.sum(a*b, axis=-1), err_msg=msg)
        x = np.arange(24).reshape(2, 3, 4)
        a = x.T
        b = x.T
        a[0, 0, 0] = -1
        assert_equal(x[0, 0, 0], -1, err_msg=msg2)
        assert_array_equal(umt.inner1d(a, b), np.sum(a*b, axis=-1), err_msg=msg)

    def test_output_argument(self):
        msg = "output argument"
        a = np.arange(12).reshape((2, 3, 2))
        b = np.arange(4).reshape((2, 1, 2)) + 1
        c = np.zeros((2, 3), dtype='int')
        umt.inner1d(a, b, c)
        assert_array_equal(c, np.sum(a*b, axis=-1), err_msg=msg)
        c[:] = -1
        umt.inner1d(a, b, out=c)
        assert_array_equal(c, np.sum(a*b, axis=-1), err_msg=msg)

        msg = "output argument with type cast"
        c = np.zeros((2, 3), dtype='int16')
        umt.inner1d(a, b, c)
        assert_array_equal(c, np.sum(a*b, axis=-1), err_msg=msg)
        c[:] = -1
        umt.inner1d(a, b, out=c)
        assert_array_equal(c, np.sum(a*b, axis=-1), err_msg=msg)

        msg = "output argument with incontiguous layout"
        c = np.zeros((2, 3, 4), dtype='int16')
        umt.inner1d(a, b, c[..., 0])
        assert_array_equal(c[..., 0], np.sum(a*b, axis=-1), err_msg=msg)
        c[:] = -1
        umt.inner1d(a, b, out=c[..., 0])
        assert_array_equal(c[..., 0], np.sum(a*b, axis=-1), err_msg=msg)

    def test_innerwt(self):
        a = np.arange(6).reshape((2, 3))
        b = np.arange(10, 16).reshape((2, 3))
        w = np.arange(20, 26).reshape((2, 3))
        assert_array_equal(umt.innerwt(a, b, w), np.sum(a*b*w, axis=-1))
        a = np.arange(100, 124).reshape((2, 3, 4))
        b = np.arange(200, 224).reshape((2, 3, 4))
        w = np.arange(300, 324).reshape((2, 3, 4))
        assert_array_equal(umt.innerwt(a, b, w), np.sum(a*b*w, axis=-1))

    def test_innerwt_empty(self):
        """Test generalized ufunc with zero-sized operands"""
        a = np.array([], dtype='f8')
        b = np.array([], dtype='f8')
        w = np.array([], dtype='f8')
        assert_array_equal(umt.innerwt(a, b, w), np.sum(a*b*w, axis=-1))

    def test_matrix_multiply(self):
        self.compare_matrix_multiply_results(np.long)
        self.compare_matrix_multiply_results(np.double)

    def compare_matrix_multiply_results(self, tp):
        d1 = np.array(rand(2, 3, 4), dtype=tp)
        d2 = np.array(rand(2, 3, 4), dtype=tp)
        msg = "matrix multiply on type %s" % d1.dtype.name

        def permute_n(n):
            if n == 1:
                return ([0],)
            ret = ()
            base = permute_n(n-1)
            for perm in base:
                for i in range(n):
                    new = perm + [n-1]
                    new[n-1] = new[i]
                    new[i] = n-1
                    ret += (new,)
            return ret

        def slice_n(n):
            if n == 0:
                return ((),)
            ret = ()
            base = slice_n(n-1)
            for sl in base:
                ret += (sl+(slice(None),),)
                ret += (sl+(slice(0, 1),),)
            return ret

        def broadcastable(s1, s2):
            return s1 == s2 or s1 == 1 or s2 == 1

        permute_3 = permute_n(3)
        slice_3 = slice_n(3) + ((slice(None, None, -1),)*3,)

        ref = True
        for p1 in permute_3:
            for p2 in permute_3:
                for s1 in slice_3:
                    for s2 in slice_3:
                        a1 = d1.transpose(p1)[s1]
                        a2 = d2.transpose(p2)[s2]
                        ref = ref and a1.base != None
                        ref = ref and a2.base != None
                        if broadcastable(a1.shape[-1], a2.shape[-2]) and \
                           broadcastable(a1.shape[0], a2.shape[0]):
                            assert_array_almost_equal(
                                umt.matrix_multiply(a1, a2),
                                np.sum(a2[..., np.newaxis].swapaxes(-3, -1) *
                                       a1[..., np.newaxis,:], axis=-1),
                                err_msg = msg+' %s %s' % (str(a1.shape),
                                                          str(a2.shape)))

        assert_equal(ref, True, err_msg="reference check")

    def test_object_logical(self):
        a = np.array([3, None, True, False, "test", ""], dtype=object)
        assert_equal(np.logical_or(a, None),
                        np.array([x or None for x in a], dtype=object))
        assert_equal(np.logical_or(a, True),
                        np.array([x or True for x in a], dtype=object))
        assert_equal(np.logical_or(a, 12),
                        np.array([x or 12 for x in a], dtype=object))
        assert_equal(np.logical_or(a, "blah"),
                        np.array([x or "blah" for x in a], dtype=object))

        assert_equal(np.logical_and(a, None),
                        np.array([x and None for x in a], dtype=object))
        assert_equal(np.logical_and(a, True),
                        np.array([x and True for x in a], dtype=object))
        assert_equal(np.logical_and(a, 12),
                        np.array([x and 12 for x in a], dtype=object))
        assert_equal(np.logical_and(a, "blah"),
                        np.array([x and "blah" for x in a], dtype=object))

        assert_equal(np.logical_not(a),
                        np.array([not x for x in a], dtype=object))

        assert_equal(np.logical_or.reduce(a), 3)
        assert_equal(np.logical_and.reduce(a), None)

    def test_object_array_reduction(self):
        # Reductions on object arrays
        a = np.array(['a', 'b', 'c'], dtype=object)
        assert_equal(np.sum(a), 'abc')
        assert_equal(np.max(a), 'c')
        assert_equal(np.min(a), 'a')
        a = np.array([True, False, True], dtype=object)
        assert_equal(np.sum(a), 2)
        assert_equal(np.prod(a), 0)
        assert_equal(np.any(a), True)
        assert_equal(np.all(a), False)
        assert_equal(np.max(a), True)
        assert_equal(np.min(a), False)

    def test_zerosize_reduction(self):
        # Test with default dtype and object dtype
        for a in [[], np.array([], dtype=object)]:
            assert_equal(np.sum(a), 0)
            assert_equal(np.prod(a), 1)
            assert_equal(np.any(a), False)
            assert_equal(np.all(a), True)
            assert_raises(ValueError, np.max, a)
            assert_raises(ValueError, np.min, a)

    def test_axis_out_of_bounds(self):
        a = np.array([False, False])
        assert_raises(ValueError, a.all, axis=1)
        a = np.array([False, False])
        assert_raises(ValueError, a.all, axis=-2)

        a = np.array([False, False])
        assert_raises(ValueError, a.any, axis=1)
        a = np.array([False, False])
        assert_raises(ValueError, a.any, axis=-2)

    def test_scalar_reduction(self):
        # The functions 'sum', 'prod', etc allow specifying axis=0
        # even for scalars
        assert_equal(np.sum(3, axis=0), 3)
        assert_equal(np.prod(3.5, axis=0), 3.5)
        assert_equal(np.any(True, axis=0), True)
        assert_equal(np.all(False, axis=0), False)
        assert_equal(np.max(3, axis=0), 3)
        assert_equal(np.min(2.5, axis=0), 2.5)

        # Check scalar behaviour for ufuncs without an identity
        assert_equal(np.power.reduce(3), 3)

        # Make sure that scalars are coming out from this operation
        assert_(type(np.prod(np.float32(2.5), axis=0)) is np.float32)
        assert_(type(np.sum(np.float32(2.5), axis=0)) is np.float32)
        assert_(type(np.max(np.float32(2.5), axis=0)) is np.float32)
        assert_(type(np.min(np.float32(2.5), axis=0)) is np.float32)

        # check if scalars/0-d arrays get cast
        assert_(type(np.any(0, axis=0)) is np.bool_)

        # assert that 0-d arrays get wrapped
        class MyArray(np.ndarray):
            pass
        a = np.array(1).view(MyArray)
        assert_(type(np.any(a)) is MyArray)


    def test_casting_out_param(self):
        # Test that it's possible to do casts on output
        a = np.ones((200, 100), np.int64)
        b = np.ones((200, 100), np.int64)
        c = np.ones((200, 100), np.float64)
        np.add(a, b, out=c)
        assert_equal(c, 2)

        a = np.zeros(65536)
        b = np.zeros(65536, dtype=np.float32)
        np.subtract(a, 0, out=b)
        assert_equal(b, 0)

    def test_where_param(self):
        # Test that the where= ufunc parameter works with regular arrays
        a = np.arange(7)
        b = np.ones(7)
        c = np.zeros(7)
        np.add(a, b, out=c, where=(a % 2 == 1))
        assert_equal(c, [0, 2, 0, 4, 0, 6, 0])

        a = np.arange(4).reshape(2, 2) + 2
        np.power(a, [2, 3], out=a, where=[[0, 1], [1, 0]])
        assert_equal(a, [[2, 27], [16, 5]])
        # Broadcasting the where= parameter
        np.subtract(a, 2, out=a, where=[True, False])
        assert_equal(a, [[0, 27], [14, 5]])

    def test_where_param_buffer_output(self):
        # This test is temporarily skipped because it requires
        # adding masking features to the nditer to work properly

        # With casting on output
        a = np.ones(10, np.int64)
        b = np.ones(10, np.int64)
        c = 1.5 * np.ones(10, np.float64)
        np.add(a, b, out=c, where=[1, 0, 0, 1, 0, 0, 1, 1, 1, 0])
        assert_equal(c, [2, 1.5, 1.5, 2, 1.5, 1.5, 2, 2, 2, 1.5])

    def check_identityless_reduction(self, a):
        # np.minimum.reduce is a identityless reduction

        # Verify that it sees the zero at various positions
        a[...] = 1
        a[1, 0, 0] = 0
        assert_equal(np.minimum.reduce(a, axis=None), 0)
        assert_equal(np.minimum.reduce(a, axis=(0, 1)), [0, 1, 1, 1])
        assert_equal(np.minimum.reduce(a, axis=(0, 2)), [0, 1, 1])
        assert_equal(np.minimum.reduce(a, axis=(1, 2)), [1, 0])
        assert_equal(np.minimum.reduce(a, axis=0),
                                    [[0, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=1),
                                    [[1, 1, 1, 1], [0, 1, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=2),
                                    [[1, 1, 1], [0, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=()), a)

        a[...] = 1
        a[0, 1, 0] = 0
        assert_equal(np.minimum.reduce(a, axis=None), 0)
        assert_equal(np.minimum.reduce(a, axis=(0, 1)), [0, 1, 1, 1])
        assert_equal(np.minimum.reduce(a, axis=(0, 2)), [1, 0, 1])
        assert_equal(np.minimum.reduce(a, axis=(1, 2)), [0, 1])
        assert_equal(np.minimum.reduce(a, axis=0),
                                    [[1, 1, 1, 1], [0, 1, 1, 1], [1, 1, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=1),
                                    [[0, 1, 1, 1], [1, 1, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=2),
                                    [[1, 0, 1], [1, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=()), a)

        a[...] = 1
        a[0, 0, 1] = 0
        assert_equal(np.minimum.reduce(a, axis=None), 0)
        assert_equal(np.minimum.reduce(a, axis=(0, 1)), [1, 0, 1, 1])
        assert_equal(np.minimum.reduce(a, axis=(0, 2)), [0, 1, 1])
        assert_equal(np.minimum.reduce(a, axis=(1, 2)), [0, 1])
        assert_equal(np.minimum.reduce(a, axis=0),
                                    [[1, 0, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=1),
                                    [[1, 0, 1, 1], [1, 1, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=2),
                                    [[0, 1, 1], [1, 1, 1]])
        assert_equal(np.minimum.reduce(a, axis=()), a)

    def test_identityless_reduction_corder(self):
        a = np.empty((2, 3, 4), order='C')
        self.check_identityless_reduction(a)

    def test_identityless_reduction_forder(self):
        a = np.empty((2, 3, 4), order='F')
        self.check_identityless_reduction(a)

    def test_identityless_reduction_otherorder(self):
        a = np.empty((2, 4, 3), order='C').swapaxes(1, 2)
        self.check_identityless_reduction(a)

    def test_identityless_reduction_noncontig(self):
        a = np.empty((3, 5, 4), order='C').swapaxes(1, 2)
        a = a[1:, 1:, 1:]
        self.check_identityless_reduction(a)

    def test_identityless_reduction_noncontig_unaligned(self):
        a = np.empty((3*4*5*8 + 1,), dtype='i1')
        a = a[1:].view(dtype='f8')
        a.shape = (3, 4, 5)
        a = a[1:, 1:, 1:]
        self.check_identityless_reduction(a)

    def test_identityless_reduction_nonreorderable(self):
        a = np.array([[8.0, 2.0, 2.0], [1.0, 0.5, 0.25]])

        res = np.divide.reduce(a, axis=0)
        assert_equal(res, [8.0, 4.0, 8.0])

        res = np.divide.reduce(a, axis=1)
        assert_equal(res, [2.0, 8.0])

        res = np.divide.reduce(a, axis=())
        assert_equal(res, a)

        assert_raises(ValueError, np.divide.reduce, a, axis=(0, 1))

    def test_reduce_zero_axis(self):
        # If we have a n x m array and do a reduction with axis=1, then we are
        # doing n reductions, and each reduction takes an m-element array. For
        # a reduction operation without an identity, then:
        #   n > 0, m > 0: fine
        #   n = 0, m > 0: fine, doing 0 reductions of m-element arrays
        #   n > 0, m = 0: can't reduce a 0-element array, ValueError
        #   n = 0, m = 0: can't reduce a 0-element array, ValueError (for
        #     consistency with the above case)
        # This test doesn't actually look at return values, it just checks to
        # make sure that error we get an error in exactly those cases where we
        # expect one, and assumes the calculations themselves are done
        # correctly.
        def ok(f, *args, **kwargs):
            f(*args, **kwargs)
        def err(f, *args, **kwargs):
            assert_raises(ValueError, f, *args, **kwargs)
        def t(expect, func, n, m):
            expect(func, np.zeros((n, m)), axis=1)
            expect(func, np.zeros((m, n)), axis=0)
            expect(func, np.zeros((n // 2, n // 2, m)), axis=2)
            expect(func, np.zeros((n // 2, m, n // 2)), axis=1)
            expect(func, np.zeros((n, m // 2, m // 2)), axis=(1, 2))
            expect(func, np.zeros((m // 2, n, m // 2)), axis=(0, 2))
            expect(func, np.zeros((m // 3, m // 3, m // 3,
                                  n // 2, n //2)),
                                 axis=(0, 1, 2))
            # Check what happens if the inner (resp. outer) dimensions are a
            # mix of zero and non-zero:
            expect(func, np.zeros((10, m, n)), axis=(0, 1))
            expect(func, np.zeros((10, n, m)), axis=(0, 2))
            expect(func, np.zeros((m, 10, n)), axis=0)
            expect(func, np.zeros((10, m, n)), axis=1)
            expect(func, np.zeros((10, n, m)), axis=2)
        # np.maximum is just an arbitrary ufunc with no reduction identity
        assert_equal(np.maximum.identity, None)
        t(ok, np.maximum.reduce, 30, 30)
        t(ok, np.maximum.reduce, 0, 30)
        t(err, np.maximum.reduce, 30, 0)
        t(err, np.maximum.reduce, 0, 0)
        err(np.maximum.reduce, [])
        np.maximum.reduce(np.zeros((0, 0)), axis=())

        # all of the combinations are fine for a reduction that has an
        # identity
        t(ok, np.add.reduce, 30, 30)
        t(ok, np.add.reduce, 0, 30)
        t(ok, np.add.reduce, 30, 0)
        t(ok, np.add.reduce, 0, 0)
        np.add.reduce([])
        np.add.reduce(np.zeros((0, 0)), axis=())

        # OTOH, accumulate always makes sense for any combination of n and m,
        # because it maps an m-element array to an m-element array. These
        # tests are simpler because accumulate doesn't accept multiple axes.
        for uf in (np.maximum, np.add):
            uf.accumulate(np.zeros((30, 0)), axis=0)
            uf.accumulate(np.zeros((0, 30)), axis=0)
            uf.accumulate(np.zeros((30, 30)), axis=0)
            uf.accumulate(np.zeros((0, 0)), axis=0)

    def test_safe_casting(self):
        # In old versions of numpy, in-place operations used the 'unsafe'
        # casting rules. In some future version, 'same_kind' will become the
        # default.
        a = np.array([1, 2, 3], dtype=int)
        # Non-in-place addition is fine
        assert_array_equal(assert_no_warnings(np.add, a, 1.1),
                           [2.1, 3.1, 4.1])
        assert_warns(DeprecationWarning, np.add, a, 1.1, out=a)
        assert_array_equal(a, [2, 3, 4])
        def add_inplace(a, b):
            a += b
        assert_warns(DeprecationWarning, add_inplace, a, 1.1)
        assert_array_equal(a, [3, 4, 5])
        # Make sure that explicitly overriding the warning is allowed:
        assert_no_warnings(np.add, a, 1.1, out=a, casting="unsafe")
        assert_array_equal(a, [4, 5, 6])

        # There's no way to propagate exceptions from the place where we issue
        # this deprecation warning, so we must throw the exception away
        # entirely rather than cause it to be raised at some other point, or
        # trigger some other unsuspecting if (PyErr_Occurred()) { ...} at some
        # other location entirely.
        import warnings
        import sys
        if sys.version_info[0] >= 3:
            from io import StringIO
        else:
            from StringIO import StringIO
        with warnings.catch_warnings():
            warnings.simplefilter("error")
            old_stderr = sys.stderr
            try:
                sys.stderr = StringIO()
                # No error, but dumps to stderr
                a += 1.1
                # No error on the next bit of code executed either
                1 + 1
                assert_("Implicitly casting" in sys.stderr.getvalue())
            finally:
                sys.stderr = old_stderr

    def test_ufunc_custom_out(self):
        # Test ufunc with built in input types and custom output type

        a = np.array([0, 1, 2], dtype='i8')
        b = np.array([0, 1, 2], dtype='i8')
        c = np.empty(3, dtype=rational)

        # Output must be specified so numpy knows what
        # ufunc signature to look for
        result = test_add(a, b, c)
        assert_equal(result, np.array([0, 2, 4], dtype=rational))

        # no output type should raise TypeError
        assert_raises(TypeError, test_add, a, b)

    def test_operand_flags(self):
        a = np.arange(16, dtype='l').reshape(4, 4)
        b = np.arange(9, dtype='l').reshape(3, 3)
        opflag_tests.inplace_add(a[:-1, :-1], b)
        assert_equal(a, np.array([[0, 2, 4, 3], [7, 9, 11, 7],
            [14, 16, 18, 11], [12, 13, 14, 15]], dtype='l'))

        a = np.array(0)
        opflag_tests.inplace_add(a, 3)
        assert_equal(a, 3)
        opflag_tests.inplace_add(a, [3, 4])
        assert_equal(a, 10)

    def test_struct_ufunc(self):
        import numpy.core.struct_ufunc_test as struct_ufunc

        a = np.array([(1, 2, 3)], dtype='u8,u8,u8')
        b = np.array([(1, 2, 3)], dtype='u8,u8,u8')

        result = struct_ufunc.add_triplet(a, b)
        assert_equal(result, np.array([(2, 4, 6)], dtype='u8,u8,u8'))

    def test_custom_ufunc(self):
        a = np.array([rational(1, 2), rational(1, 3), rational(1, 4)],
            dtype=rational);
        b = np.array([rational(1, 2), rational(1, 3), rational(1, 4)],
            dtype=rational);

        result = test_add_rationals(a, b)
        expected = np.array([rational(1), rational(2, 3), rational(1, 2)],
            dtype=rational);
        assert_equal(result, expected);

    def test_custom_array_like(self):
        class MyThing(object):
            __array_priority__ = 1000

            rmul_count = 0
            getitem_count = 0

            def __init__(self, shape):
                self.shape = shape

            def __len__(self):
                return self.shape[0]

            def __getitem__(self, i):
                MyThing.getitem_count += 1
                if not isinstance(i, tuple):
                    i = (i,)
                if len(i) > len(self.shape):
                    raise IndexError("boo")

                return MyThing(self.shape[len(i):])

            def __rmul__(self, other):
                MyThing.rmul_count += 1
                return self

        np.float64(5)*MyThing((3, 3))
        assert_(MyThing.rmul_count == 1, MyThing.rmul_count)
        assert_(MyThing.getitem_count <= 2, MyThing.getitem_count)

    def test_inplace_fancy_indexing(self):

        a = np.arange(10)
        np.add.at(a, [2, 5, 2], 1)
        assert_equal(a, [0, 1, 4, 3, 4, 6, 6, 7, 8, 9])

        a = np.arange(10)
        b = np.array([100, 100, 100])
        np.add.at(a, [2, 5, 2], b)
        assert_equal(a, [0, 1, 202, 3, 4, 105, 6, 7, 8, 9])

        a = np.arange(9).reshape(3, 3)
        b = np.array([[100, 100, 100], [200, 200, 200], [300, 300, 300]])
        np.add.at(a, (slice(None), [1, 2, 1]), b)
        assert_equal(a, [[0, 201, 102], [3, 404, 205], [6, 607, 308]])

        a = np.arange(27).reshape(3, 3, 3)
        b = np.array([100, 200, 300])
        np.add.at(a, (slice(None), slice(None), [1, 2, 1]), b)
        assert_equal(a,
            [[[0, 401, 202],
              [3, 404, 205],
              [6, 407, 208]],

             [[9, 410, 211],
              [12, 413, 214],
              [15, 416, 217]],

             [[18, 419, 220],
              [21, 422, 223],
              [24, 425, 226]]])

        a = np.arange(9).reshape(3, 3)
        b = np.array([[100, 100, 100], [200, 200, 200], [300, 300, 300]])
        np.add.at(a, ([1, 2, 1], slice(None)), b)
        assert_equal(a, [[0, 1, 2], [403, 404, 405], [206, 207, 208]])

        a = np.arange(27).reshape(3, 3, 3)
        b = np.array([100, 200, 300])
        np.add.at(a, (slice(None), [1, 2, 1], slice(None)), b)
        assert_equal(a,
            [[[0,  1,  2  ],
              [203, 404, 605],
              [106, 207, 308]],

             [[9,  10, 11 ],
              [212, 413, 614],
              [115, 216, 317]],

             [[18, 19, 20 ],
              [221, 422, 623],
              [124, 225, 326]]])

        a = np.arange(9).reshape(3, 3)
        b = np.array([100, 200, 300])
        np.add.at(a, (0, [1, 2, 1]), b)
        assert_equal(a, [[0, 401, 202], [3, 4, 5], [6, 7, 8]])

        a = np.arange(27).reshape(3, 3, 3)
        b = np.array([100, 200, 300])
        np.add.at(a, ([1, 2, 1], 0, slice(None)), b)
        assert_equal(a,
            [[[0,  1,  2],
              [3,  4,  5],
              [6,  7,  8]],

             [[209, 410, 611],
              [12,  13, 14],
              [15,  16, 17]],

             [[118, 219, 320],
              [21,  22, 23],
              [24,  25, 26]]])

        a = np.arange(27).reshape(3, 3, 3)
        b = np.array([100, 200, 300])
        np.add.at(a, (slice(None), slice(None), slice(None)), b)
        assert_equal(a,
            [[[100, 201, 302],
              [103, 204, 305],
              [106, 207, 308]],

             [[109, 210, 311],
              [112, 213, 314],
              [115, 216, 317]],

             [[118, 219, 320],
              [121, 222, 323],
              [124, 225, 326]]])

        a = np.arange(10)
        np.negative.at(a, [2, 5, 2])
        assert_equal(a, [0, 1, 2, 3, 4, -5, 6, 7, 8, 9])

        # Test 0-dim array
        a = np.array(0)
        np.add.at(a, (), 1)
        assert_equal(a, 1)

        assert_raises(IndexError, np.add.at, a, 0, 1)
        assert_raises(IndexError, np.add.at, a, [], 1)

        # Test mixed dtypes
        a = np.arange(10)
        np.power.at(a, [1, 2, 3, 2], 3.5)
        assert_equal(a, np.array([0, 1, 4414, 46, 4, 5, 6, 7, 8, 9]))

        # Test boolean indexing and boolean ufuncs
        a = np.arange(10)
        index = a % 2 == 0
        np.equal.at(a, index, [0, 2, 4, 6, 8])
        assert_equal(a, [1, 1, 1, 3, 1, 5, 1, 7, 1, 9])

        # Test unary operator
        a = np.arange(10, dtype='u4')
        np.invert.at(a, [2, 5, 2])
        assert_equal(a, [0, 1, 2, 3, 4, 5 ^ 0xffffffff, 6, 7, 8, 9])

        # Test empty subspace
        orig = np.arange(4)
        a = orig[:, None][:, 0:0]
        np.add.at(a, [0, 1], 3)
        assert_array_equal(orig, np.arange(4))

        # Test with swapped byte order
        index = np.array([1, 2, 1], np.dtype('i').newbyteorder())
        values = np.array([1, 2, 3, 4], np.dtype('f').newbyteorder())
        np.add.at(values, index, 3)
        assert_array_equal(values, [1, 8, 6, 4])

        # Test exception thrown
        values = np.array(['a', 1], dtype=np.object)
        self.assertRaises(TypeError, np.add.at, values, [0, 1], 1)
        assert_array_equal(values, np.array(['a', 1], dtype=np.object))

if __name__ == "__main__":
    run_module_suite()
