Python numpy.logaddexp2函数代码示例

 def test_nan(self):
     err = np.seterr(invalid="ignore")
     try:
         assert np.isnan(np.logaddexp2(np.nan, np.inf))
         assert np.isnan(np.logaddexp2(np.inf, np.nan))
         assert np.isnan(np.logaddexp2(np.nan, 0))
         assert np.isnan(np.logaddexp2(0, np.nan))
         assert np.isnan(np.logaddexp2(np.nan, np.nan))
     finally:
         np.seterr(**err)

    def _nllx(xi, i):
        ll = 0.0
        zi[0] = sum(xi ** 2.0)
        zi[1 : k + 1] = xi
        for j in range(l):
            gij = snp_matrix[i, j]
            if gij == geosnp.MISSING:
                continue
            qnf = zi.T.dot(Y[j])
            r = numpy.logaddexp2(-qnf, 0)
            r2 = numpy.logaddexp2(qnf, 0)
            ll -= (gij * r) + ((2.0 - gij) * (r2))

        # return NLL in order to minimize
        return -ll

    def _nlly(yj, j):
        ll = 0.0
        q, a, b = yj[0], yj[1 : k + 1], yj[-1]
        for i in range(n):
            gij = snp_matrix[i, j]
            if gij == geosnp.MISSING:
                continue
            xi = X[i]
            qnf = (q * sum(xi ** 2.0)) + a.dot(xi) + b
            r = numpy.logaddexp2(-qnf, 0)
            r2 = numpy.logaddexp2(qnf, 0)
            ll -= (gij * r) + ((2.0 - gij) * (r2))

        # return NLL in order to minimize
        return -ll

 def _increment_by_frecency(self, frecency_added, multiplier=1.):
     """Increment this frecency by another frecency, with optional multiplier.
     NOTE: No attempt is made here to handle differing timescales or other parameters.
     """
     log2_multiplier = log2(multiplier)
     log2_weight_added = frecency_added.log2_value + log2_multiplier
     self.log2_value = logaddexp2(self.log2_value, log2_weight_added)

 def add(self, x, y):
     # Convert log_b probabilities to log_2 probabilities.
     x2 = x * np.log2(base)
     y2 = y * np.log2(base)
     z = np.logaddexp2(x2, y2)
     # Convert log_2 probabilities to log_b probabilities.
     z *= self.log(2)
     return z

    def _baum_welch_step(self, sequence, model, symbol_to_number):

        N = len(model._states)
        M = len(model._symbols)
        T = len(sequence)

        # compute forward and backward probabilities
        alpha = model._forward_probability(sequence)
        beta = model._backward_probability(sequence)

        # find the log probability of the sequence
        lpk = logsumexp2(alpha[T - 1])

        A_numer = _ninf_array((N, N))
        B_numer = _ninf_array((N, M))
        A_denom = _ninf_array(N)
        B_denom = _ninf_array(N)

        transitions_logprob = model._transitions_matrix().T

        for t in range(T):
            symbol = sequence[t][_TEXT]  # not found? FIXME
            next_symbol = None
            if t < T - 1:
                next_symbol = sequence[t + 1][_TEXT]  # not found? FIXME
            xi = symbol_to_number[symbol]

            next_outputs_logprob = model._outputs_vector(next_symbol)
            alpha_plus_beta = alpha[t] + beta[t]

            if t < T - 1:
                numer_add = (
                    transitions_logprob
                    + next_outputs_logprob
                    + beta[t + 1]
                    + alpha[t].reshape(N, 1)
                )
                A_numer = np.logaddexp2(A_numer, numer_add)
                A_denom = np.logaddexp2(A_denom, alpha_plus_beta)
            else:
                B_denom = np.logaddexp2(A_denom, alpha_plus_beta)

            B_numer[:, xi] = np.logaddexp2(B_numer[:, xi], alpha_plus_beta)

        return lpk, A_numer, A_denom, B_numer, B_denom

 def test_logaddexp2_range(self):
     x = [1000000, -1000000, 1000200, -1000200]
     y = [1000200, -1000200, 1000000, -1000000]
     z = [1000200, -1000000, 1000200, -1000000]
     for dt in ["f", "d", "g"]:
         logxf = np.array(x, dtype=dt)
         logyf = np.array(y, dtype=dt)
         logzf = np.array(z, dtype=dt)
         assert_almost_equal(np.logaddexp2(logxf, logyf), logzf)

 def test_logaddexp2_values(self):
     x = [1, 2, 3, 4, 5]
     y = [5, 4, 3, 2, 1]
     z = [6, 6, 6, 6, 6]
     for dt, dec in zip(["f", "d", "g"], [6, 15, 15]):
         xf = np.log2(np.array(x, dtype=dt))
         yf = np.log2(np.array(y, dtype=dt))
         zf = np.log2(np.array(z, dtype=dt))
         assert_almost_equal(np.logaddexp2(xf, yf), zf, decimal=dec)

def misc_floating(mod, x):
    "miscellaneous"
    # y0  = math.erfc(x)

    y1  = math.atan2(x, x)
    y2  = np.arctan2(x, x)
    y3  = np.logaddexp(x, x)
    y4  = np.logaddexp2(x, x)
    return (y1, y2, y3, y4) #(y0, y1)

 def test_inf(self):
     inf = np.inf
     x = [inf, -inf, inf, -inf, inf, 1, -inf, 1]
     y = [inf, inf, -inf, -inf, 1, inf, 1, -inf]
     z = [inf, inf, inf, -inf, inf, inf, 1, 1]
     for dt in ["f", "d", "g"]:
         logxf = np.array(x, dtype=dt)
         logyf = np.array(y, dtype=dt)
         logzf = np.array(z, dtype=dt)
         assert_equal(np.logaddexp2(logxf, logyf), logzf)

 def increment(self, value_added=1., event_time=None):
     """
     Increment frecency, with value_added weighted according to time of observation.
     
     * *value_added* is the number or weight of current events to add to the Frecency counter.  (e.g., 1 for one view)
     * *event_time* can be used to set the time at which the new value was added; otherwise, the present time is used.
     """
     if not event_time:
         event_time = time.time()
     log2_weight_added = (event_time - self.time0) / self.timescale + log2(value_added)
     self.log2_value = logaddexp2(self.log2_value, log2_weight_added)  # All calculations in log2 space to avoid overflow

 def test_inf(self) :
     inf = np.inf
     x = [inf, -inf,  inf, -inf, inf, 1,  -inf,  1]
     y = [inf,  inf, -inf, -inf, 1,   inf, 1,   -inf]
     z = [inf,  inf,  inf, -inf, inf, inf, 1,    1]
     with np.errstate(invalid='ignore'):
         for dt in ['f', 'd', 'g'] :
             logxf = np.array(x, dtype=dt)
             logyf = np.array(y, dtype=dt)
             logzf = np.array(z, dtype=dt)
             assert_equal(np.logaddexp2(logxf, logyf), logzf)

 def test_inf(self):
     err = np.seterr(invalid="ignore")
     inf = np.inf
     x = [inf, -inf, inf, -inf, inf, 1, -inf, 1]
     y = [inf, inf, -inf, -inf, 1, inf, 1, -inf]
     z = [inf, inf, inf, -inf, inf, inf, 1, 1]
     try:
         for dt in ["f", "d", "g"]:
             logxf = np.array(x, dtype=dt)
             logyf = np.array(y, dtype=dt)
             logzf = np.array(z, dtype=dt)
             assert_equal(np.logaddexp2(logxf, logyf), logzf)
     finally:
         np.seterr(**err)

 def add_inplace(self, x, y):
     x *= np.log2(base)
     y2 = y * np.log2(base)
     np.logaddexp2(x, y2, x)
     x *= self.log(2)
     return x

    def test_logaddexp2(self):
        import math
        import sys

        float_max, float_min = sys.float_info.max, sys.float_info.min
        from numpy import logaddexp2

        log2 = math.log(2)

        # From the numpy documentation
        prob1 = math.log(1e-50) / log2
        prob2 = math.log(2.5e-50) / log2
        prob12 = logaddexp2(prob1, prob2)
        assert math.fabs(-164.28904982231052 - prob12) < 0.000000000001

        assert logaddexp2(0, 0) == 1
        assert logaddexp2(float("-inf"), 0) == 0
        assert logaddexp2(float_max, float_max) == float_max
        assert logaddexp2(float_min, float_min) == 1.0

        assert math.isnan(logaddexp2(float("nan"), 1))
        assert math.isnan(logaddexp2(1, float("nan")))
        assert math.isnan(logaddexp2(float("nan"), float("inf")))
        assert math.isnan(logaddexp2(float("inf"), float("nan")))
        assert logaddexp2(float("-inf"), float("-inf")) == float("-inf")
        assert logaddexp2(float("-inf"), float("inf")) == float("inf")
        assert logaddexp2(float("inf"), float("-inf")) == float("inf")
        assert logaddexp2(float("inf"), float("inf")) == float("inf")