from __future__ import division
from __future__ import unicode_literals
from __future__ import print_function
from __future__ import absolute_import
from future import standard_library
standard_library.install_aliases()
import unittest
from SimPEG.Utils import Zero, Identity, sdiag, mkvc
from SimPEG import np, sp

class Tests(unittest.TestCase):

    def test_zero(self):
        z = Zero()
        assert z == 0
        assert not (z < 0)
        assert z <= 0
        assert not (z > 0)
        assert z >= 0
        assert +z == z
        assert -z == z
        assert z + 1 == 1
        assert z + 3 +z == 3
        assert z - 3  == -3
        assert z - 3 -z == -3
        assert 3*z == 0
        assert z*3 == 0
        assert old_div(z,3) == 0

        a = 1
        a += z
        assert a == 1
        a = 1
        a += z
        assert a == 1
        self.assertRaises(ZeroDivisionError, lambda:old_div(3,z))

        assert mkvc(z) == 0
        assert sdiag(z)*a == 0
        assert z.T == 0
        assert z.transpose == 0

    def test_mat_zero(self):
        z = Zero()
        S = sdiag(np.r_[2,3])
        assert S*z == 0

    def test_one(self):
        o = Identity()
        assert o == 1
        assert not (o < 1)
        assert o <= 1
        assert not (o > 1)
        assert o >= 1
        o = -o
        assert o == -1
        assert not (o < -1)
        assert o <= -1
        assert not (o > -1)
        assert o >= -1
        assert -(-o)*o == -o
        o = Identity()
        assert +o == o
        assert -o == -o
        assert o*3 == 3
        assert -o*3 == -3
        assert -o*o == -1
        assert -o*o*-o == 1
        assert -o + 3 == 2
        assert 3 + -o == 2

        assert -o - 3 == -4
        assert o - 3 == -2
        assert 3 - -o == 4
        assert 3 - o == 2

        assert old_div(o,2) == 0
        assert old_div(o,2.) == 0.5
        assert old_div(-o,2) == -1
        assert old_div(-o,2.) == -0.5
        assert old_div(2,o) == 2
        assert old_div(2,-o) == -2


    def test_mat_one(self):

        o = Identity()
        S = sdiag(np.r_[2,3])
        def check(exp,ans):
            assert np.all((exp).todense() == ans)

        check(S * o, [[2,0],[0,3]])
        check(o * S, [[2,0],[0,3]])
        check(S * -o, [[-2,0],[0,-3]])
        check(-o * S, [[-2,0],[0,-3]])
        check(old_div(S,o), [[2,0],[0,3]])
        check(old_div(S,-o), [[-2,0],[0,-3]])
        self.assertRaises(NotImplementedError, lambda:old_div(o,S))

        check(S + o, [[3,0],[0,4]])
        check(o + S, [[3,0],[0,4]])

        check(S + - o, [[1,0],[0,2]])
        check(S   - o, [[1,0],[0,2]])
        check(- o + S, [[1,0],[0,2]])

    def test_mat_shape(self):
        o = Identity()
        S = sdiag(np.r_[2,3])[:1,:]
        self.assertRaises(ValueError, lambda:S + o)
        def check(exp,ans):
            assert np.all((exp).todense() == ans)
        check(S * o, [[2,0]])
        check(S * -o, [[-2,0]])

    def test_numpy_one(self):
        o = Identity()
        n = np.r_[2.,3]
        assert np.all(n+1 == n+o)
        assert np.all(1+n == o+n)
        assert np.all(n-1 == n-o)
        assert np.all(1-n == o-n)
        assert np.all(old_div(n,1) == old_div(n,o))
        assert np.all(old_div(n,-1) == old_div(n,-o))
        assert np.all(old_div(1,n) == old_div(o,n))
        assert np.all(old_div(-1,n) == old_div(-o,n))
        assert np.all(n*1 == n*o)
        assert np.all(n*-1 == n*-o)
        assert np.all(1*n == o*n)
        assert np.all(-1*n == -o*n)

    def test_both(self):
        z = Zero()
        o = Identity()
        assert o*z == 0
        assert o*z + o == 1
        assert o-z == 1



if __name__ == '__main__':
    unittest.main()