Python pyds.MassFunction类代码示例

 def test_gbt(self):
     def test(m, places):
         self.assertAlmostEqual(0.3 * 0.8 / (1 - 0.7 * 0.2), m['ab'], places)
         self.assertAlmostEqual(0.3 * 0.2 / (1 - 0.7 * 0.2), m['a'], places)
         self.assertAlmostEqual(0.7 * 0.8 / (1 - 0.7 * 0.2), m['b'], places)
     pl = [('a', 0.3), ('b', 0.8), ('c', 0.0)]
     test(MassFunction.gbt(pl), 10)
     test(MassFunction.gbt(pl, sample_count=10000), 2)
     pl = {'a':0.3, 'b':0.8, 'c':0.0, 'd':1.0}
     self._assert_equal_belief(MassFunction.gbt(pl), MassFunction.gbt(pl, sample_count=10000), 1)

 def test_markov(self):
     def test(m, places):
         self.assertAlmostEqual(0.4 * 0.8, m[(4, 6)], places)
         self.assertAlmostEqual(0.4 * 0.2, m[(5,)], places)
         self.assertAlmostEqual(0.6 * 0.2 * 0.2, m[(0, 1)], places)
         self.assertAlmostEqual(0.6 * 0.2 * 0.8, m[(-1, 1)], places)
         self.assertAlmostEqual(0.6 * 0.2 * 0.8, m[(0, 2)], places)
         self.assertAlmostEqual(0.6 * 0.8 * 0.8, m[(-1, 0, 1, 2)], places)
     m = MassFunction([((0, 1), 0.6), ((5,), 0.4)])
     transition_model = lambda s: MassFunction([((s - 1, s + 1), 0.8), ((s,), 0.2)])
     transition_model_mc = lambda s, n: transition_model(s).sample(n)
     test(m.markov(transition_model), 10)
     test(m.markov(transition_model_mc, sample_count=10000), 2)

 def test_combine_gbt(self):
     pl = [('b', 0.8), ('c', 0.5)]
     correct = self.m1.combine_conjunctive(MassFunction.gbt(pl))
     self._assert_equal_belief(correct, self.m1.combine_gbt(pl), 10)
     self._assert_equal_belief(self.m1.combine_gbt(pl), self.m1.combine_gbt(pl, sample_count=10000), 1)
     self._assert_equal_belief(self.m2.combine_gbt(pl), self.m2.combine_gbt(pl, sample_count=10000), 1)
     # Bayesian special case
     p_prior = self.m1.pignistic()
     p_posterior = p_prior.combine_gbt(pl)
     p_correct = MassFunction()
     for s, l in pl:
         p_correct[(s,)] = l * p_prior[(s,)]
     p_correct.normalize()
     self._assert_equal_belief(p_correct, p_posterior, 10)

 def test_combine_cautious(self):
     """
     Examples from:
     T. Denoeux (2008), "Conjunctive and disjunctive combination of belief functions induced by nondistinct bodies of evidence",
     Artificial Intelligence 172, 234-264.
     """
     m1 = MassFunction({'ab':0.3, 'bc':0.5, 'abc':0.2})
     m2 = MassFunction({'b':0.3, 'bc':0.4, 'abc':0.3})
     m = m1.combine_cautious(m2)
     self.assertAlmostEqual(0.0, m[''])
     self.assertAlmostEqual(0.0, m['a'])
     self.assertAlmostEqual(0.6, m['b'])
     self.assertAlmostEqual(0.12, m['ab'])
     self.assertAlmostEqual(0.0, m['c'])
     self.assertAlmostEqual(0.0, m['ac'])
     self.assertAlmostEqual(0.2, m['bc'])
     self.assertAlmostEqual(0.08, m['abc'])

 def test_from_samples(self):
     """
     Example 1 (default) and example 7 (ordered) from:
     T. Denoeux (2006), "Constructing belief functions from sample data using multinomial confidence regions",
     International Journal of Approximate Reasoning 42, 228-252.
     
     Example 6 (consonant) from:
     A. Aregui, T. Denoeux (2008), "Constructing consonant belief functions from sample data using confidence sets of pignistic probabilities",
     International Journal of Approximate Reasoning 49, 575-594.
     """
     precipitation_data = {1:48, 2:17, 3:19, 4:11, 5:6, 6:9}
     failure_mode_data = {1:5, 2:11, 3:19, 4:30, 5:58, 6:67, 7:92, 8:118, 9:173, 10:297}
     psych_data = {1:91, 2:49, 3:37, 4:43}
     # default
     m = MassFunction.from_samples(psych_data, 0.05, mode='default')
     p_lower, p_upper = MassFunction._confidence_intervals(psych_data, 0.05)
     def p_lower_set(hs):
         l = u = 0
         for h in psych_data.keys():
             if h in hs:
                 l += p_lower[h]
             else:
                 u += p_upper[h]
         return max(l, 1 - u)
     bel_sum = 0
     for h in m.all():
         bel = m.bel(h)
         bel_sum += bel
         self.assertLessEqual(bel, p_lower_set(h)) # constraint (24)
     self.assertEqual(1, sum(m.values())) # constraint (25)
     self.assertGreaterEqual(min(m.values()), 0) # constraint (26)
     self.assertGreaterEqual(bel_sum, 6.23) # optimization criterion
     # ordered
     m = MassFunction.from_samples(precipitation_data, 0.05, mode='ordered')
     self.assertAlmostEqual(0.32,  m[(1,)], 2)
     self.assertAlmostEqual(0.085, m[(2,)], 3)
     self.assertAlmostEqual(0.098, m[(3,)], 3)
     self.assertAlmostEqual(0.047, m[(4,)], 3)
     self.assertAlmostEqual(0.020, m[(5,)], 3)
     self.assertAlmostEqual(0.035, m[(6,)], 3)
     self.assertAlmostEqual(0.13,  m[range(1, 5)], 2)
     self.assertAlmostEqual(0.11,  m[range(1, 6)], 2)
     self.assertAlmostEqual(0.012, m[range(2, 6)], 2)
     self.assertAlmostEqual(0.14,  m[range(2, 7)], 2)
     # consonant
     poss = {1: 0.171, 2: 0.258, 3: 0.353, 4: 0.462, 5: 0.688, 6: 0.735, 7: 0.804, 8: 0.867, 9: 0.935, 10: 1.0} # 8: 0.873
     m = MassFunction.from_samples(failure_mode_data, 0.1, mode='consonant') 
     self._assert_equal_belief(MassFunction.from_possibility(poss), m, 1)
     # consonant-approximate
     m = MassFunction.from_samples(failure_mode_data, 0.1, mode='consonant-approximate')
     poss = {1: 0.171, 2: 0.258, 3: 0.353, 4: 0.462, 5: 0.688, 6: 0.747, 7: 0.875, 8: 0.973, 9: 1.0, 10: 1.0} 
     self._assert_equal_belief(MassFunction.from_possibility(poss), m, 2)
     # bayesian
     m = MassFunction.from_samples(precipitation_data, 0.05, mode='bayesian')
     for e, n in precipitation_data.items():
         self.assertEqual(n / sum(precipitation_data.values()), m[(e,)]) 

 def test_pignistic_inverse(self):
     """
     Example 1 from:
     A. Aregui, T. Denoeux (2008), "Constructing consonant belief functions from sample data using confidence sets of pignistic probabilities",
     International Journal of Approximate Reasoning 49, 575-594.
     """
     p = MassFunction({'a':0.7, 'b':0.2, 'c':0.1})
     m = MassFunction.pignistic_inverse(p)
     self.assertEqual(0.5, m['a'])
     self.assertAlmostEqual(0.2, m['ab'])
     self.assertAlmostEqual(0.3, m['abc'])

 def test_from_possibility(self):
     """
     Example 1 from:
     D. Dubois, H. Prade, P. Smets (2008), "A definition of subjective possibility",
     International Journal of Approximate Reasoning 48 (2), 352-364.
     """
     x = 0.6
     poss = {'a':1, 'b':x, 'c':1-x}
     m = MassFunction.from_possibility(poss)
     self.assertEqual(1 - x, m['a'])
     self.assertEqual(2 * x - 1, m['ab'])
     self.assertEqual(1 - x, m['abc'])

 def test_weight_function(self):
     """
     Examples from:
     T. Denoeux (2008), "Conjunctive and disjunctive combination of belief functions induced by nondistinct bodies of evidence",
     Artificial Intelligence 172, 234-264.
     """
     m1 = MassFunction({'ab':0.3, 'bc':0.5, 'abc':0.2})
     w1 = m1.weight_function()
     self.assertAlmostEqual(1.0, w1[frozenset('')])
     self.assertAlmostEqual(1.0, w1[frozenset('a')])
     self.assertAlmostEqual(7./4., w1[frozenset('b')])
     self.assertAlmostEqual(2./5., w1[frozenset('ab')])
     self.assertAlmostEqual(1.0, w1[frozenset('c')])
     self.assertAlmostEqual(1.0, w1[frozenset('ac')])
     self.assertAlmostEqual(2./7., w1[frozenset('bc')])
     m2 = MassFunction({'b':0.3, 'bc':0.4, 'abc':0.3})
     w2 = m2.weight_function()
     self.assertAlmostEqual(1.0, w2[frozenset('')])
     self.assertAlmostEqual(1.0, w2[frozenset('a')])
     self.assertAlmostEqual(0.7, w2[frozenset('b')])
     self.assertAlmostEqual(1.0, w2[frozenset('ab')])
     self.assertAlmostEqual(1.0, w2[frozenset('c')])
     self.assertAlmostEqual(1.0, w2[frozenset('ac')])
     self.assertAlmostEqual(3./7., w2[frozenset('bc')])

 def test_confidence_intervals(self):
     """
     Numbers taken from:
     W.L. May, W.D. Johnson, A SAS macro for constructing simultaneous confidence intervals for multinomial proportions,
     Computer methods and Programs in Biomedicine 53 (1997) 153–162.
     """
     hist = {1:91, 2:49, 3:37, 4:43}
     lower, upper = MassFunction._confidence_intervals(hist, 0.05)
     self.assertAlmostEqual(0.33, lower[1], places=2)
     self.assertAlmostEqual(0.16, lower[2], places=2)
     self.assertAlmostEqual(0.11, lower[3], places=2)
     self.assertAlmostEqual(0.14, lower[4], places=2)
     for h, p_u in upper.items():
         p = hist[h] / sum(hist.values())
         self.assertAlmostEqual(2 * p - lower[h], p_u, places=1)

def error_combine_conjunctive_1000_dir():
    m1 = MassFunction.gbt(random_likelihoods(6))
    m2 = MassFunction.gbt(random_likelihoods(6))
    return measure_error(m1 & m2, m1.combine_conjunctive, m2, sample_count=1000, importance_sampling=False)

def error_gbt_1000():
    lh = random_likelihoods(10)
    return measure_error(MassFunction.gbt(lh), MassFunction.gbt, lh, sample_count=1000)

def time_markov_1000():
    samples = MassFunction.gbt(random_likelihoods(4)).sample(1000)
    return measure_time(MassFunction.gbt(random_likelihoods(4)).markov, lambda s, n: samples[:n], sample_count=1000)

def time_markov():
    m = MassFunction.gbt(random_likelihoods(4))
    return measure_time(MassFunction.gbt(random_likelihoods(4)).markov, lambda s: m)

def time_pignistic():
    return measure_time(MassFunction.gbt(random_likelihoods(12)).pignistic)

def time_combine_gbt_1000_imp():
    return measure_time(MassFunction.gbt(random_likelihoods(6)).combine_gbt, random_likelihoods(6), sample_count=1000, importance_sampling=True)