Python numpy.mean函数代码示例

def figure_2_4():
    """Replicate figure 2.4 of Sutton and Barto's book."""
    print('Running figure 2.4 simulation ...')
    np.random.seed(1234)
    epsilons = (0.1, 0)
    q_inits = (0, 5)
    ars, pos = [], []
    for epsilon, q_init in zip(epsilons, q_inits):
        ar, po = run_experiment(2000, 1000, epsilon=epsilon, Q_init=q_init,
                                alpha=0.1)
        ars.append(np.mean(ar, 0))
        pos.append(np.mean(po, 0))
        
    # plot the results
    plt.close('all')
    f, (ax1, ax2) = plt.subplots(2)
    labels = ('$\epsilon$-greedy', 'optimistic')
    for i,label in enumerate(labels):
        ax1.plot(ars[i].T, label=label)
        ax2.plot(pos[i].T, label=label)
    ax1.legend(loc='lower right')
    ax1.set_ylabel('Average reward')
    ax1.set_xlim(xmin=-10)
    ax2.legend(loc='lower right')
    ax2.set_xlabel('Plays')
    ax2.set_ylabel('% Optimal action')
    ax2.set_xlim(xmin=-20)
    plt.savefig('fig_2_4.pdf')
    plt.show()

def getIdealWins(errors, testErrors, p=0.01): 
    """
    Figure out whether the ideal error obtained using the test set is an improvement 
    over model selection using CV. 
    """
    winsShape = list(errors.shape[1:-1]) 
    winsShape.append(3)
    stdWins = numpy.zeros(winsShape, numpy.int)
       
    for i in range(len(sampleSizes)):
        for j in range(foldsSet.shape[0]): 
            s1 = errors[:, i, j, 0]
            s2 = testErrors[:, i]
            
            s1Mean = numpy.mean(s1)
            s2Mean = numpy.mean(s2)                
            
            t, prob = scipy.stats.wilcoxon(s1, s2)
            if prob < p: 
                if s1Mean > s2Mean: 
                    stdWins[i, j, 2] = 1 
                elif s1Mean < s2Mean:
                    stdWins[i, j, 0] = 1
            else: 
                print("Test draw samplesize:" + str(sampleSizes[i]) + " folds " + str(foldsSet[j]))
                stdWins[i, j, 1] = 1 
                    
    return stdWins

def add_noise_evoked(evoked, noise, snr, tmin=None, tmax=None):
    """Adds noise to evoked object with specified SNR.

    SNR is computed in the interval from tmin to tmax.

    Parameters
    ----------
    evoked : Evoked object
        An instance of evoked with signal
    noise : Evoked object
        An instance of evoked with noise
    snr : float
        signal to noise ratio in dB. It corresponds to
        10 * log10( var(signal) / var(noise) )
    tmin : float
        start time before event
    tmax : float
        end time after event

    Returns
    -------
    evoked_noise : Evoked object
        An instance of evoked corrupted by noise
    """
    evoked = copy.deepcopy(evoked)
    tmask = _time_mask(evoked.times, tmin, tmax)
    tmp = 10 * np.log10(np.mean((evoked.data[:, tmask] ** 2).ravel()) /
                        np.mean((noise.data ** 2).ravel()))
    noise.data = 10 ** ((tmp - float(snr)) / 20) * noise.data
    evoked.data += noise.data
    return evoked

    def work(self, **kwargs):
        self.__dict__.update(kwargs)
        self.worked = True
        samples = LGMM1(rng=self.rng,
                size=(self.n_samples,),
                **self.LGMM1_kwargs)
        samples = np.sort(samples)
        edges = samples[::self.samples_per_bin]
        centers = .5 * edges[:-1] + .5 * edges[1:]
        print edges

        pdf = np.exp(LGMM1_lpdf(centers, **self.LGMM1_kwargs))
        dx = edges[1:] - edges[:-1]
        y = 1 / dx / len(dx)

        if self.show:
            plt.scatter(centers, y)
            plt.plot(centers, pdf)
            plt.show()
        err = (pdf - y) ** 2
        print np.max(err)
        print np.mean(err)
        print np.median(err)
        if not self.show:
            assert np.max(err) < .1
            assert np.mean(err) < .01
            assert np.median(err) < .01

def Haffine_from_points(fp, tp):
    '''计算仿射变换的单应性矩阵H，使得tp是由fp经过仿射变换得到的'''
    if fp.shape != tp.shape:
        raise RuntimeError('number of points do not match')

    # 对点进行归一化
    # 映射起始点
    m = numpy.mean(fp[:2], axis=1)
    maxstd = numpy.max(numpy.std(fp[:2], axis=1)) + 1e-9
    C1 = numpy.diag([1/maxstd, 1/maxstd, 1])
    C1[0, 2] = -m[0] / maxstd
    C1[1, 2] = -m[1] / maxstd
    fp_cond = numpy.dot(C1, fp)

    # 映射对应点
    m = numpy.mean(tp[:2], axis=1)
    maxstd = numpy.max(numpy.std(tp[:2], axis=1)) + 1e-9
    C2 = numpy.diag([1/maxstd, 1/maxstd, 1])
    C2[0, 2] = -m[0] / maxstd
    C2[1, 2] = -m[1] / maxstd
    tp_cond = numpy.dot(C2, tp)

    # 因为归一化之后点的均值为0，所以平移量为0
    A = numpy.concatenate((fp_cond[:2], tp_cond[:2]), axis=0)
    U, S, V = numpy.linalg.svd(A.T)
    # 创建矩阵B和C
    tmp = V[:2].T
    B = tmp[:2]
    C = tmp[2:4]

    tmp2 = numpy.concatenate((numpy.dot(C, numpy.linalg.pinv(B)), numpy.zeros((2, 1))), axis=1)
    H = numpy.vstack((tmp2, [0, 0, 1]))

    H = numpy.dot(numpy.linalg.inv(C2), numpy.dot(H, C1))  # 反归一化
    return H / H[2, 2]  # 归一化，然后返回

def trainer(model, data, epochs, validate_period, model_path, prob_lm=0.1, runid=''):
    def valid_loss():
        result = dict(lm=[], visual=[])
        for item in data.iter_valid_batches():
            result['lm'].append(model.lm.loss_test(*model.lm.args(item)))
            result['visual'].append(model.visual.loss_test(*model.visual.args(item)))
        return result
    costs = Counter(dict(cost_v=0.0, N_v=0.0, cost_t=0.0, N_t=0.0))
    print "LM: {} parameters".format(count_params(model.lm.params()))
    print "Vi: {} parameters".format(count_params(model.visual.params()))
    for epoch in range(1,epochs+1):
        for _j, item in enumerate(data.iter_train_batches()):
            j = _j +1
            if random.random() <= prob_lm:
                cost_t = model.lm.train(*model.lm.args(item))
                costs += Counter(dict(cost_t=cost_t, N_t=1))
            else:
                cost_v = model.visual.train(*model.visual.args(item))
                costs += Counter(dict(cost_v=cost_v, N_v=1))
            print epoch, j, j*data.batch_size, "train", \
                    numpy.divide(costs['cost_v'], costs['N_v']),\
                    numpy.divide(costs['cost_t'], costs['N_t'])
            if j % validate_period == 0:
                result = valid_loss()
                print epoch, j, 0, "valid", \
                    numpy.mean(result['visual']),\
                    numpy.mean(result['lm'])
                sys.stdout.flush()
        model.save(path='model.r{}.e{}.zip'.format(runid, epoch))
    model.save(path='model.zip')

def sample_every_two_correlation_times(energy_data, magnetization_data, correlation_time, no_of_sites):
    """Sample the given data every 2 correlation times and determine value and error."""
    magnet_samples = []
    energy_samples = []

    for t in np.arange(0, len(energy_data), 2 * int(np.ceil(correlation_time))):
        magnet_samples.append(magnetization_data[t])
        energy_samples.append(energy_data[t])

    magnet_samples = np.asarray(magnet_samples)
    energy_samples = np.asarray(energy_samples)

    abs_magnetization = np.mean(np.absolute(magnet_samples))
    abs_magnetization_error = calculate_error(magnet_samples)
    print("<m> (<|M|/N>) = {0} +/- {1}".format(abs_magnetization, abs_magnetization_error))

    magnetization = np.mean(magnet_samples)
    magnetization_error = calculate_error(magnet_samples)
    print("<M/N> = {0} +/- {1}".format(magnetization, magnetization_error))

    energy = np.mean(energy_samples)
    energy_error = calculate_error(energy_samples)
    print("<E/N> = {0} +/- {1}".format(energy, energy_error))

    magnetization_squared = np.mean((magnet_samples * no_of_sites)**2)
    magnetization_squared_error = calculate_error((magnet_samples * no_of_sites)**2)
    print("<M^2> = {0} +/- {1}".format(magnetization_squared, magnetization_squared_error))

def modulate_image(gabor_def,
                    visuals,
                    spacials,
                    position,
                    min_contrast=0.0,
                    frequency_data=None,
                    use_local_rms=False):
    
    (pixels_per_degree, gabor_diameter, xf, yf, gaussian, ramp, grating, g) = frequency_data if isinstance(frequency_data, FREQ_DATA) else load_spacial_data(visuals, spacials)
    import time
    st = time.time()
    top_left_pos = (position[0] - (gabor_diameter / 2.0), position[1] - (gabor_diameter / 2.0))
    
    patch = gabor_def.rms_matrix[top_left_pos[0] : top_left_pos[0] + gabor_diameter, top_left_pos[1] : top_left_pos[1] + gabor_diameter, :]
    
    if use_local_rms:
        patch_avg = gabor_def.avg_matrix[top_left_pos[0] : top_left_pos[0] + gabor_diameter, top_left_pos[1] : top_left_pos[1] + gabor_diameter]
        R = (patch_avg / 127.0) - 1
        R = R / (numpy.max(numpy.abs(R))) / 2.0
        rms_measure = numpy.std(R + 0.5) / numpy.mean(R + 0.5)
        print rms_measure
        if min_contrast > 0:
            rms_measure = max(rms_measure, min_contrast)
        g = g * (255.0 * rms_measure)
    else:
        g = g * (255.0 * gabor_def.rms_measure)
    
    g = g - numpy.mean(g)
    
    gabor = numpy.transpose(numpy.tile(g, (3,1,1)), (1,2,0))
    print "took {0}".format((time.time() - st) * 1000.0)
    return GABOR_DATA._make([top_left_pos, gabor_diameter, gabor_diameter / 2.0, patch, numpy.clip(patch + gabor, 0, 255).astype('uint8')])

    def update(self, y):
    
        L = Loss().MSE(self.output, y)
        
        # stopping criteria
        self.errors[self.epoch%5] =  numpy.mean(L.E**2)**0.5
        score = numpy.mean(self.errors)    
            
        # stop when error starts to diverge too much
        print " " , self.bestScore
        self.stop = score/self.bestScore > 1e60
        
        # save the best weights
        if score < self.bestScore:
            self.bestW = self.W
            self.bestScore = score
            self.bestEpoch = self.epoch
        norm_W = numpy.linalg.norm(self.W)
        sys.stdout.write( "\rEpoch %d: RMSE: %2.3f, Norm(W): %2.2f"%(self.epoch, numpy.mean((y-self.output)**2)**0.5, norm_W) )
        sys.stdout.flush()
        
        # gradients
        grad_outputs = L.dE_dY*(1 - self.output**2)
        dE_dK = numpy.dot(self.hidden.reshape(self.n_hidden, 1), grad_outputs.reshape(1, self.n_output))
        
        transfer = numpy.dot(grad_outputs, self.K.T)        
               
        # hidden layer
        grad_hidden =  transfer * (1 - self.hidden**2) 
        dE_dW = numpy.dot(self.X.T , grad_hidden)

        # updating weights
        self.K -= 1.2*self.alpha*dE_dK
        
        self.W -= self.alpha*dE_dW

 def testPdfOfSampleMultiDims(self):
   student = student_t.StudentT(df=[7., 11.], loc=[[5.], [6.]], scale=3.)
   self.assertAllEqual([], student.event_shape)
   self.assertAllEqual([], self.evaluate(student.event_shape_tensor()))
   self.assertAllEqual([2, 2], student.batch_shape)
   self.assertAllEqual([2, 2], self.evaluate(student.batch_shape_tensor()))
   num = 50000
   samples = student.sample(num, seed=123456)
   pdfs = student.prob(samples)
   sample_vals, pdf_vals = self.evaluate([samples, pdfs])
   self.assertEqual(samples.get_shape(), (num, 2, 2))
   self.assertEqual(pdfs.get_shape(), (num, 2, 2))
   self.assertNear(5., np.mean(sample_vals[:, 0, :]), err=.03)
   self.assertNear(6., np.mean(sample_vals[:, 1, :]), err=.03)
   self._assertIntegral(sample_vals[:, 0, 0], pdf_vals[:, 0, 0], err=0.02)
   self._assertIntegral(sample_vals[:, 0, 1], pdf_vals[:, 0, 1], err=0.02)
   self._assertIntegral(sample_vals[:, 1, 0], pdf_vals[:, 1, 0], err=0.02)
   self._assertIntegral(sample_vals[:, 1, 1], pdf_vals[:, 1, 1], err=0.02)
   if not stats:
     return
   self.assertNear(
       stats.t.var(7., loc=0., scale=3.),  # loc d.n. effect var
       np.var(sample_vals[:, :, 0]),
       err=.4)
   self.assertNear(
       stats.t.var(11., loc=0., scale=3.),  # loc d.n. effect var
       np.var(sample_vals[:, :, 1]),
       err=.4)

 def testEpsilon_MOEA_NegativeDTLZ2(self):
     random = pyotl.utility.Random(1)
     problemGen = lambda: pyotl.problem.real.NegativeDTLZ2(3)
     problem = problemGen()
     pathProblem = os.path.join(self.pathData, type(problem).__name__.replace('Negative', ''), str(problem.GetNumberOfObjectives()))
     crossover = pyotl.crossover.real.SimulatedBinaryCrossover(random, 1, problem.GetBoundary(), 20)
     mutation = pyotl.mutation.real.PolynomialMutation(random, 1 / float(len(problem.GetBoundary())), problem.GetBoundary(), 20)
     epsilon = pyotl.utility.PyList2Vector_Real([0.06] * problem.GetNumberOfObjectives())
     pfList = []
     for _ in range(self.repeat):
         problem = problemGen()
         initial = pyotl.initial.real.BatchUniform(random, problem.GetBoundary(), 100)
         optimizer = pyotl.optimizer.couple_couple.real.Epsilon_MOEA(random, problem, initial, crossover, mutation, epsilon)
         while optimizer.GetProblem().GetNumberOfEvaluations() < 30000:
             optimizer()
         pf = pyotl.utility.PyListList2VectorVector_Real(
             [list(solution.objective_) for solution in optimizer.GetSolutionSet()])
         for objective in pf:
             problem.Fix(objective)
         pfList.append(pf)
     pathCrossover = os.path.join(pathProblem, type(crossover).__name__)
     pathOptimizer = os.path.join(pathCrossover, type(optimizer).__name__)
     pfTrue = pyotl.utility.PyListList2VectorVector_Real(numpy.loadtxt(os.path.join(pathProblem, 'PF.csv')).tolist())
     # GD
     indicator = pyotl.indicator.real.DTLZ2GD()
     metricList = [indicator(pf) for pf in pfList]
     rightList = numpy.loadtxt(os.path.join(pathOptimizer, 'GD.csv')).tolist()
     self.assertGreater(scipy.stats.ttest_ind(rightList, metricList)[1], 0.05, [numpy.mean(rightList), numpy.mean(metricList), metricList])
     # IGD
     indicator = pyotl.indicator.real.InvertedGenerationalDistance(pfTrue)
     metricList = [indicator(pf) for pf in pfList]
     rightList = numpy.loadtxt(os.path.join(pathOptimizer, 'IGD.csv')).tolist()
     self.assertGreater(scipy.stats.ttest_ind(rightList, metricList)[1], 0.05, [numpy.mean(rightList), numpy.mean(metricList), metricList])

def SB_MotifTwo(y,binarizeHow='diff'):
    """
    Looks at local motifs in a binary symbolization of the time series, which is performed by a
    given binarization method
    
    Arguments
    ---------

    y: a nitime time-series object, or numpy vector

    """
    
    # Make the input a row vector of numbers:
    y = makeRowVector(vectorize(y))

    # Make binarization on incremental differences:
    if binarizeHow == 'diff':
        yBin = ((np.sign(np.diff(y)))+1.)/2.
    else:
        raise ValueError(binarizeHow)
        
    # Initialize output dictionary
    out = {}
    
    # Where the difference is 0, 1
    r0 = yBin==0
    r1 = yBin==1
    

    out['u'] = np.mean(r1)
    out['d'] = np.mean(r0)
    out['h'] = -(out['u']*np.log2(out['u']) + out['d']*np.log2(out['d']))
    
    return out

def EN_CID(y):
    """
    CID measure from Batista, G. E. A. P. A., Keogh, E. J., Tataw, O. M. & de
    Souza, V. M. A. CID: an efficient complexity-invariant distance for time
    series. Data Min Knowl. Disc. 28, 634-669 (2014).
    
    Arguments
    ---------

    y: a nitime time-series object, or numpy vector

    """

    # Make the input a row vector of numbers:
    y = makeRowVector(vectorize(y))

    # Prepare the output dictionary
    out = {}
    
     # Original definition (in Table 2 of paper cited above)
    out['CE1'] = np.sqrt(np.mean(np.power(np.diff(y),2))); # sum -> mean to deal with non-equal time-series lengths

    # Definition corresponding to the line segment example in Fig. 9 of the paper
    # cited above (using Pythagoras's theorum):
    out['CE2'] = np.mean(np.sqrt(1 + np.power(np.diff(y),2)));

    return out

def softmax_experiment():
    """Run softmax experiment."""
    print('Running softmax experiment.')
    taus = [0.01, 0.1, 1]
    ars, pos = [], []
    for tau in taus:
        ar, po = run_experiment(2000, 1000, tau=tau, alpha=0.1)
        ars.append
        ars.append(np.mean(ar, 0))
        pos.append(np.mean(po, 0))
        
    # plot the results
    plt.close('all')
    f, (ax1, ax2) = plt.subplots(2)
    for i,tau in enumerate(taus):
        ax1.plot(ars[i].T, label='$\\tau$ = %.2f' % tau)
        ax2.plot(pos[i].T, label='$\\tau$ = %.2f' % tau)
    ax1.legend(loc='lower right')
    ax1.set_ylabel('Average reward')
    ax1.set_xlim(xmin=-10)
    ax2.legend(loc='lower right')
    ax2.set_xlabel('Plays')
    ax2.set_ylabel('% Optimal action')
    ax2.set_xlim(xmin=-20)
    plt.savefig('softmax_experiment.pdf')
    plt.show()

def getClass(imageWindow, models,z):
	hasLabel=False
	label=999
	for k in models.keys():
		m=models[k]
		l1=m[0]
		l2=m[1]
		l3=m[2]
		
		h1=m[3]
		h2=m[4]
		h3=m[5]

		ch1=numpy.mean(imageWindow[:,:,0])
		ch2=numpy.mean(imageWindow[:,:,1])
		ch3=numpy.mean(imageWindow[:,:,2])
		#print "checking if ", ch1, ch2, ch3, " is between ", h1, l1, h2, l2, h3, l3
		if(l1<ch1<h1 and l2<ch2<h2 and l3<ch3<h3):
			if(not hasLabel):
				label=k
				print "got label ", z[k]
				hasLabel=True
			else:
				print "error, relabeling as :", z[k]
				return 999
	if(not hasLabel):
		return 999
	else:
		return label