def statistics_kmm (n,d): from modshogun import RealFeatures from modshogun import DataGenerator from modshogun import GaussianKernel, MSG_DEBUG from modshogun import KernelMeanMatching from modshogun import Math # init seed for reproducability Math.init_random(1) random.seed(1); data = random.randn(d,n) # create shogun feature representation features=RealFeatures(data) # use a kernel width of sigma=2, which is 8 in SHOGUN's parametrization # which is k(x,y)=exp(-||x-y||^2 / tau), in constrast to the standard # k(x,y)=exp(-||x-y||^2 / (2*sigma^2)), so tau=2*sigma^2 kernel=GaussianKernel(10,8) kernel.init(features,features) kmm = KernelMeanMatching(kernel,array([0,1,2,3,7,8,9],dtype=int32),array([4,5,6],dtype=int32)) w = kmm.compute_weights() #print w return w
def kernel_io_modular(train_fname=traindat, test_fname=testdat, width=1.9):
from modshogun import RealFeatures, GaussianKernel, CSVFile
feats_train = RealFeatures(CSVFile(train_fname))
feats_test = RealFeatures(CSVFile(test_fname))
kernel = GaussianKernel(feats_train, feats_train, width)
km_train = kernel.get_kernel_matrix()
f = CSVFile("tmp/gaussian_train.csv", "w")
kernel.save(f)
del f
kernel.init(feats_train, feats_test)
km_test = kernel.get_kernel_matrix()
f = CSVFile("tmp/gaussian_test.csv", "w")
kernel.save(f)
del f
# clean up
import os
os.unlink("tmp/gaussian_test.csv")
os.unlink("tmp/gaussian_train.csv")
return km_train, km_test, kernel
def kernel_gaussian_modular (train_fname=traindat,test_fname=testdat, width=1.3): from modshogun import RealFeatures, GaussianKernel, CSVFile feats_train=RealFeatures(CSVFile(train_fname)) feats_test=RealFeatures(CSVFile(test_fname)) kernel=GaussianKernel(feats_train, feats_train, width) km_train=kernel.get_kernel_matrix() kernel.init(feats_train, feats_test) km_test=kernel.get_kernel_matrix() return km_train,km_test,kernel
def kernel_sparse_gaussian_modular (fm_train_real=traindat,fm_test_real=testdat,width=1.1 ): from modshogun import SparseRealFeatures from modshogun import GaussianKernel feats_train=SparseRealFeatures(fm_train_real) feats_test=SparseRealFeatures(fm_test_real) kernel=GaussianKernel(feats_train, feats_train, width) km_train=kernel.get_kernel_matrix() kernel.init(feats_train, feats_test) km_test=kernel.get_kernel_matrix() return km_train,km_test,kernel
def classifier_multiclasslibsvm_modular (fm_train_real=traindat,fm_test_real=testdat,label_train_multiclass=label_traindat,width=2.1,C=1,epsilon=1e-5): from modshogun import RealFeatures, MulticlassLabels from modshogun import GaussianKernel from modshogun import MulticlassLibSVM feats_train=RealFeatures(fm_train_real) feats_test=RealFeatures(fm_test_real) kernel=GaussianKernel(feats_train, feats_train, width) labels=MulticlassLabels(label_train_multiclass) svm=MulticlassLibSVM(C, kernel, labels) svm.set_epsilon(epsilon) svm.train() kernel.init(feats_train, feats_test) out = svm.apply().get_labels() predictions = svm.apply() return predictions, svm, predictions.get_labels()
def regression_kernel_ridge_modular (n=100,n_test=100, \ x_range=6,x_range_test=10,noise_var=0.5,width=1, tau=1e-6, seed=1): from modshogun import RegressionLabels, RealFeatures from modshogun import GaussianKernel from modshogun import KernelRidgeRegression # reproducable results random.seed(seed) # easy regression data: one dimensional noisy sine wave n=15 n_test=100 x_range_test=10 noise_var=0.5; X=random.rand(1,n)*x_range X_test=array([[float(i)/n_test*x_range_test for i in range(n_test)]]) Y_test=sin(X_test) Y=sin(X)+random.randn(n)*noise_var # shogun representation labels=RegressionLabels(Y[0]) feats_train=RealFeatures(X) feats_test=RealFeatures(X_test) kernel=GaussianKernel(feats_train, feats_train, width) krr=KernelRidgeRegression(tau, kernel, labels) krr.train(feats_train) kernel.init(feats_train, feats_test) out = krr.apply().get_labels() # plot results #plot(X[0],Y[0],'x') # training observations #plot(X_test[0],Y_test[0],'-') # ground truth of test #plot(X_test[0],out, '-') # mean predictions of test #legend(["training", "ground truth", "mean predictions"]) #show() return out,kernel,krr
def regression_libsvr_modular (svm_c=1, svr_param=0.1, n=100,n_test=100, \ x_range=6,x_range_test=10,noise_var=0.5,width=1, seed=1): from modshogun import RegressionLabels, RealFeatures from modshogun import GaussianKernel from modshogun import LibSVR, LIBSVR_NU_SVR, LIBSVR_EPSILON_SVR # reproducable results random.seed(seed) # easy regression data: one dimensional noisy sine wave n=15 n_test=100 x_range_test=10 noise_var=0.5; X=random.rand(1,n)*x_range X_test=array([[float(i)/n_test*x_range_test for i in range(n_test)]]) Y_test=sin(X_test) Y=sin(X)+random.randn(n)*noise_var # shogun representation labels=RegressionLabels(Y[0]) feats_train=RealFeatures(X) feats_test=RealFeatures(X_test) kernel=GaussianKernel(feats_train, feats_train, width) # two svr models: epsilon and nu svr_epsilon=LibSVR(svm_c, svr_param, kernel, labels, LIBSVR_EPSILON_SVR) svr_epsilon.train() svr_nu=LibSVR(svm_c, svr_param, kernel, labels, LIBSVR_NU_SVR) svr_nu.train() # predictions kernel.init(feats_train, feats_test) out1_epsilon=svr_epsilon.apply().get_labels() out2_epsilon=svr_epsilon.apply(feats_test).get_labels() out1_nu=svr_epsilon.apply().get_labels() out2_nu=svr_epsilon.apply(feats_test).get_labels() return out1_epsilon,out2_epsilon,out1_nu,out2_nu ,kernel
def classifier_multiclassmachine_modular (fm_train_real=traindat,fm_test_real=testdat,label_train_multiclass=label_traindat,width=2.1,C=1,epsilon=1e-5): from modshogun import RealFeatures, MulticlassLabels from modshogun import GaussianKernel from modshogun import LibSVM, KernelMulticlassMachine, MulticlassOneVsRestStrategy feats_train=RealFeatures(fm_train_real) feats_test=RealFeatures(fm_test_real) kernel=GaussianKernel(feats_train, feats_train, width) labels=MulticlassLabels(label_train_multiclass) classifier = LibSVM() classifier.set_epsilon(epsilon) #print labels.get_labels() mc_classifier = KernelMulticlassMachine(MulticlassOneVsRestStrategy(),kernel,classifier,labels) mc_classifier.train() kernel.init(feats_train, feats_test) out = mc_classifier.apply().get_labels() return out
from modshogun import GaussianKernel
from modshogun import LibSVM, LDA
from modshogun import ROCEvaluation
import util
util.set_title('ROC example')
util.DISTANCE=0.5
subplots_adjust(hspace=0.3)
pos=util.get_realdata(True)
neg=util.get_realdata(False)
features=util.get_realfeatures(pos, neg)
labels=util.get_labels()
# classifiers
gk=GaussianKernel(features, features, 1.0)
svm = LibSVM(1000.0, gk, labels)
svm.train()
lda=LDA(1,features,labels)
lda.train()
## plot points
subplot(211)
plot(pos[0,:], pos[1,:], "r.")
plot(neg[0,:], neg[1,:], "b.")
grid(True)
title('Data',size=10)
# plot ROC for SVM
subplot(223)
ROC_evaluation=ROCEvaluation()
def statistics_quadratic_time_mmd (m,dim,difference): from modshogun import RealFeatures from modshogun import MeanShiftDataGenerator from modshogun import GaussianKernel, CustomKernel from modshogun import QuadraticTimeMMD from modshogun import PERMUTATION, MMD2_SPECTRUM, MMD2_GAMMA, BIASED, BIASED_DEPRECATED from modshogun import Statistics, IntVector, RealVector, Math # init seed for reproducability Math.init_random(1) random.seed(17) # number of examples kept low in order to make things fast # streaming data generator for mean shift distributions gen_p=MeanShiftDataGenerator(0, dim); #gen_p.parallel.set_num_threads(1) gen_q=MeanShiftDataGenerator(difference, dim); # stream some data from generator feat_p=gen_p.get_streamed_features(m); feat_q=gen_q.get_streamed_features(m); # set kernel a-priori. usually one would do some kernel selection. See # other examples for this. width=10; kernel=GaussianKernel(10, width); # create quadratic time mmd instance. Note that this constructor # copies p and q and does not reference them mmd=QuadraticTimeMMD(kernel, feat_p, feat_q); # perform test: compute p-value and test if null-hypothesis is rejected for # a test level of 0.05 alpha=0.05; # using permutation (slow, not the most reliable way. Consider pre- # computing the kernel when using it, see below). # Also, in practice, use at least 250 iterations mmd.set_null_approximation_method(PERMUTATION); mmd.set_num_null_samples(3); p_value_null=mmd.perform_test(); # reject if p-value is smaller than test level #print "bootstrap: p!=q: ", p_value_null<alpha # using spectrum method. Use at least 250 samples from null. # This is consistent but sometimes breaks, always monitor type I error. # See tutorial for number of eigenvalues to use . mmd.set_statistic_type(BIASED); mmd.set_null_approximation_method(MMD2_SPECTRUM); mmd.set_num_eigenvalues_spectrum(3); mmd.set_num_samples_spectrum(250); p_value_spectrum=mmd.perform_test(); # reject if p-value is smaller than test level #print "spectrum: p!=q: ", p_value_spectrum<alpha # using gamma method. This is a quick hack, which works most of the time # but is NOT guaranteed to. See tutorial for details. # Only works with BIASED_DEPRECATED statistic mmd.set_statistic_type(BIASED_DEPRECATED); mmd.set_null_approximation_method(MMD2_GAMMA); p_value_gamma=mmd.perform_test(); # reject if p-value is smaller than test level #print "gamma: p!=q: ", p_value_gamma<alpha # compute tpye I and II error (use many more trials in practice). # Type I error is not necessary if one uses permutation. We do it here # anyway, but note that this is an efficient way of computing it. # Also note that testing has to happen on # difference data than kernel selection, but the linear time mmd does this # implicitly and we used a fixed kernel here. mmd.set_statistic_type(BIASED); mmd.set_null_approximation_method(PERMUTATION); mmd.set_num_null_samples(5); num_trials=5; type_I_errors=RealVector(num_trials); type_II_errors=RealVector(num_trials); inds=int32(array([x for x in range(2*m)])) # numpy p_and_q=mmd.get_p_and_q(); # use a precomputed kernel to be faster kernel.init(p_and_q, p_and_q); precomputed=CustomKernel(kernel); mmd.set_kernel(precomputed); for i in range(num_trials): # this effectively means that p=q - rejecting is tpye I error inds=random.permutation(inds) # numpy permutation precomputed.add_row_subset(inds); precomputed.add_col_subset(inds); type_I_errors[i]=mmd.perform_test()>alpha; precomputed.remove_row_subset(); precomputed.remove_col_subset(); # on normal data, this gives type II error type_II_errors[i]=mmd.perform_test()>alpha; return type_I_errors.get(),type_I_errors.get(),p_value_null,p_value_spectrum,p_value_gamma,
def serialization_svmlight_modular(num, dist, width, C):
from modshogun import MSG_DEBUG
from modshogun import RealFeatures, BinaryLabels, DNA, Alphabet
from modshogun import WeightedDegreeStringKernel, GaussianKernel
try:
from modshogun import SVMLight
except ImportError:
print("SVMLight not available")
exit(0)
from numpy import concatenate, ones
from numpy.random import randn, seed
import sys
import types
import random
import bz2
import pickle
import inspect
def save(filename, myobj):
"""
save object to file using pickle
@param filename: name of destination file
@type filename: str
@param myobj: object to save (has to be pickleable)
@type myobj: obj
"""
try:
f = bz2.BZ2File(filename, 'wb')
except IOError as details:
sys.stderr.write('File ' + filename + ' cannot be written\n')
sys.stderr.write(details)
return
pickle.dump(myobj, f, protocol=2)
f.close()
def load(filename):
"""
Load from filename using pickle
@param filename: name of file to load from
@type filename: str
"""
try:
f = bz2.BZ2File(filename, 'rb')
except IOError as details:
sys.stderr.write('File ' + filename + ' cannot be read\n')
sys.stderr.write(details)
return
myobj = pickle.load(f)
f.close()
return myobj
##################################################
# set up toy data and svm
traindata_real = concatenate((randn(2, num) - dist, randn(2, num) + dist),
axis=1)
testdata_real = concatenate((randn(2, num) - dist, randn(2, num) + dist),
axis=1)
trainlab = concatenate((-ones(num), ones(num)))
testlab = concatenate((-ones(num), ones(num)))
feats_train = RealFeatures(traindata_real)
feats_test = RealFeatures(testdata_real)
kernel = GaussianKernel(feats_train, feats_train, width)
#kernel.io.set_loglevel(MSG_DEBUG)
labels = BinaryLabels(trainlab)
svm = SVMLight(C, kernel, labels)
svm.train()
#svm.io.set_loglevel(MSG_DEBUG)
##################################################
# serialize to file
fn = "serialized_svm.bz2"
#print("serializing SVM to file", fn)
save(fn, svm)
##################################################
# unserialize and sanity check
#print("unserializing SVM")
svm2 = load(fn)
#print("comparing objectives")
svm2.train()
#print("objective before serialization:", svm.get_objective())
#print("objective after serialization:", svm2.get_objective())
#print("comparing predictions")
out = svm.apply(feats_test).get_labels()
out2 = svm2.apply(feats_test).get_labels()
# assert outputs are close
for i in range(len(out)):
assert abs(out[i] - out2[i] < 0.000001)
#print("all checks passed.")
return True
def quadratic_time_mmd_graphical():
# parameters, change to get different results
m=100
dim=2
# setting the difference of the first dimension smaller makes a harder test
difference=0.5
# number of samples taken from null and alternative distribution
num_null_samples=500
# streaming data generator for mean shift distributions
gen_p=MeanShiftDataGenerator(0, dim)
gen_q=MeanShiftDataGenerator(difference, dim)
# Stream examples and merge them in order to compute MMD on joint sample
# alternative is to call a different constructor of QuadraticTimeMMD
features=gen_p.get_streamed_features(m)
features=features.create_merged_copy(gen_q.get_streamed_features(m))
# use the median kernel selection
# create combined kernel with Gaussian kernels inside (shoguns Gaussian kernel is
# compute median data distance in order to use for Gaussian kernel width
# 0.5*median_distance normally (factor two in Gaussian kernel)
# However, shoguns kernel width is different to usual parametrization
# Therefore 0.5*2*median_distance^2
# Use a subset of data for that, only 200 elements. Median is stable
sigmas=[2**x for x in range(-3,10)]
widths=[x*x*2 for x in sigmas]
print "kernel widths:", widths
combined=CombinedKernel()
for i in range(len(sigmas)):
combined.append_kernel(GaussianKernel(10, widths[i]))
# create MMD instance, use biased statistic
mmd=QuadraticTimeMMD(combined,features, m)
mmd.set_statistic_type(BIASED)
# kernel selection instance (this can easily replaced by the other methods for selecting
# single kernels
selection=MMDKernelSelectionMax(mmd)
# perform kernel selection
kernel=selection.select_kernel()
kernel=GaussianKernel.obtain_from_generic(kernel)
mmd.set_kernel(kernel);
print "selected kernel width:", kernel.get_width()
# sample alternative distribution (new data each trial)
alt_samples=zeros(num_null_samples)
for i in range(len(alt_samples)):
# Stream examples and merge them in order to replace in MMD
features=gen_p.get_streamed_features(m)
features=features.create_merged_copy(gen_q.get_streamed_features(m))
mmd.set_p_and_q(features)
alt_samples[i]=mmd.compute_statistic()
# sample from null distribution
# bootstrapping, biased statistic
mmd.set_null_approximation_method(BOOTSTRAP)
mmd.set_statistic_type(BIASED)
mmd.set_bootstrap_iterations(num_null_samples)
null_samples_boot=mmd.bootstrap_null()
# sample from null distribution
# spectrum, biased statistic
if "sample_null_spectrum" in dir(QuadraticTimeMMD):
mmd.set_null_approximation_method(MMD2_SPECTRUM)
mmd.set_statistic_type(BIASED)
null_samples_spectrum=mmd.sample_null_spectrum(num_null_samples, m-10)
# fit gamma distribution, biased statistic
mmd.set_null_approximation_method(MMD2_GAMMA)
mmd.set_statistic_type(BIASED)
gamma_params=mmd.fit_null_gamma()
# sample gamma with parameters
null_samples_gamma=array([gamma(gamma_params[0], gamma_params[1]) for _ in range(num_null_samples)])
# to plot data, sample a few examples from stream first
features=gen_p.get_streamed_features(m)
features=features.create_merged_copy(gen_q.get_streamed_features(m))
data=features.get_feature_matrix()
# plot
figure()
title('Quadratic Time MMD')
# plot data of p and q
subplot(2,3,1)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 4) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 4) ) # reduce number of x-ticks
plot(data[0][0:m], data[1][0:m], 'ro', label='$x$')
plot(data[0][m+1:2*m], data[1][m+1:2*m], 'bo', label='$x$', alpha=0.5)
title('Data, shift in $x_1$='+str(difference)+'\nm='+str(m))
xlabel('$x_1, y_1$')
ylabel('$x_2, y_2$')
# histogram of first data dimension and pdf
subplot(2,3,2)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3 )) # reduce number of x-ticks
hist(data[0], bins=50, alpha=0.5, facecolor='r', normed=True)
hist(data[1], bins=50, alpha=0.5, facecolor='b', normed=True)
xs=linspace(min(data[0])-1,max(data[0])+1, 50)
plot(xs,normpdf( xs, 0, 1), 'r', linewidth=3)
plot(xs,normpdf( xs, difference, 1), 'b', linewidth=3)
xlabel('$x_1, y_1$')
ylabel('$p(x_1), p(y_1)$')
title('Data PDF in $x_1, y_1$')
# compute threshold for test level
alpha=0.05
null_samples_boot.sort()
null_samples_spectrum.sort()
null_samples_gamma.sort()
thresh_boot=null_samples_boot[floor(len(null_samples_boot)*(1-alpha))];
thresh_spectrum=null_samples_spectrum[floor(len(null_samples_spectrum)*(1-alpha))];
thresh_gamma=null_samples_gamma[floor(len(null_samples_gamma)*(1-alpha))];
type_one_error_boot=sum(null_samples_boot<thresh_boot)/float(num_null_samples)
type_one_error_spectrum=sum(null_samples_spectrum<thresh_boot)/float(num_null_samples)
type_one_error_gamma=sum(null_samples_gamma<thresh_boot)/float(num_null_samples)
# plot alternative distribution with threshold
subplot(2,3,4)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
hist(alt_samples, 20, normed=True);
axvline(thresh_boot, 0, 1, linewidth=2, color='red')
type_two_error=sum(alt_samples<thresh_boot)/float(num_null_samples)
title('Alternative Dist.\n' + 'Type II error is ' + str(type_two_error))
# compute range for all null distribution histograms
hist_range=[min([min(null_samples_boot), min(null_samples_spectrum), min(null_samples_gamma)]), max([max(null_samples_boot), max(null_samples_spectrum), max(null_samples_gamma)])]
# plot null distribution with threshold
subplot(2,3,3)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3 )) # reduce number of x-ticks
hist(null_samples_boot, 20, range=hist_range, normed=True);
axvline(thresh_boot, 0, 1, linewidth=2, color='red')
title('Bootstrapped Null Dist.\n' + 'Type I error is ' + str(type_one_error_boot))
grid(True)
# plot null distribution spectrum
subplot(2,3,5)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
hist(null_samples_spectrum, 20, range=hist_range, normed=True);
axvline(thresh_spectrum, 0, 1, linewidth=2, color='red')
title('Null Dist. Spectrum\nType I error is ' + str(type_one_error_spectrum))
# plot null distribution gamma
subplot(2,3,6)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
hist(null_samples_gamma, 20, range=hist_range, normed=True);
axvline(thresh_gamma, 0, 1, linewidth=2, color='red')
title('Null Dist. Gamma\nType I error is ' + str(type_one_error_gamma))
# pull plots a bit apart
subplots_adjust(hspace=0.5)
subplots_adjust(wspace=0.5)
def regression_gaussian_process_modelselection (n=100, n_test=100, \
x_range=5, x_range_test=10, noise_var=0.4):
from modshogun import RealFeatures, RegressionLabels
from modshogun import GaussianKernel
from modshogun import GradientModelSelection, ModelSelectionParameters
from modshogun import GaussianLikelihood, ZeroMean, \
ExactInferenceMethod, GaussianProcessRegression, GradientCriterion, \
GradientEvaluation
# easy regression data: one dimensional noisy sine wave
X_train = random.rand(1, n) * x_range
X_test = array([[float(i) / n_test * x_range_test for i in range(n_test)]])
y_test = sin(X_test)
y_train = sin(X_train) + random.randn(n) * noise_var
# shogun representation
labels = RegressionLabels(y_train[0])
feats_train = RealFeatures(X_train)
feats_test = RealFeatures(X_test)
# GP specification
kernel = GaussianKernel(10, 0.05)
mean = ZeroMean()
likelihood = GaussianLikelihood(0.8)
inf = ExactInferenceMethod(kernel, feats_train, mean, labels, likelihood)
inf.set_scale(2.5)
gp = GaussianProcessRegression(inf)
means = gp.get_mean_vector(feats_test)
variances = gp.get_variance_vector(feats_test)
# plot results
figure()
subplot(2, 1, 1)
title('Initial parameter\'s values')
plot(X_train[0], y_train[0], 'bx') # training observations
plot(X_test[0], y_test[0], 'g-') # ground truth of test
plot(X_test[0], means, 'r-') # mean predictions of test
fill_between(X_test[0],
means - 1.96 * sqrt(variances),
means + 1.96 * sqrt(variances),
color='grey')
legend(["training", "ground truth", "mean predictions"])
# evaluate our inference method for its derivatives
grad = GradientEvaluation(gp, feats_train, labels, GradientCriterion(),
False)
grad.set_function(inf)
# handles all of the above structures in memory
grad_search = GradientModelSelection(grad)
# search for best parameters
best_combination = grad_search.select_model(True)
# outputs all result and information
best_combination.apply_to_machine(gp)
means = gp.get_mean_vector(feats_test)
variances = gp.get_variance_vector(feats_test)
# plot results
subplot(2, 1, 2)
title('Selected by gradient search parameter\'s values')
plot(X_train[0], y_train[0], 'bx') # training observations
plot(X_test[0], y_test[0], 'g-') # ground truth of test
plot(X_test[0], means, 'r-') # mean predictions of test
fill_between(X_test[0],
means - 1.96 * sqrt(variances),
means + 1.96 * sqrt(variances),
color='grey')
legend(["training", "ground truth", "mean predictions"])
show()
def serialization_complex_example (num=5, dist=1, dim=10, C=2.0, width=10):
import os
from numpy import concatenate, zeros, ones
from numpy.random import randn, seed
from modshogun import RealFeatures, MulticlassLabels
from modshogun import GMNPSVM
from modshogun import GaussianKernel
try:
from modshogun import SerializableHdf5File,SerializableAsciiFile, \
SerializableJsonFile,SerializableXmlFile,MSG_DEBUG
except ImportError:
return
from modshogun import NormOne, LogPlusOne
seed(17)
data=concatenate((randn(dim, num), randn(dim, num) + dist,
randn(dim, num) + 2*dist,
randn(dim, num) + 3*dist), axis=1)
lab=concatenate((zeros(num), ones(num), 2*ones(num), 3*ones(num)))
feats=RealFeatures(data)
#feats.io.set_loglevel(MSG_DEBUG)
#feats.io.enable_file_and_line()
kernel=GaussianKernel(feats, feats, width)
labels=MulticlassLabels(lab)
svm = GMNPSVM(C, kernel, labels)
feats.add_preprocessor(NormOne())
feats.add_preprocessor(LogPlusOne())
feats.set_preprocessed(1)
svm.train(feats)
bias_ref = svm.get_svm(0).get_bias()
#svm.print_serializable()
fstream = SerializableHdf5File("blaah.h5", "w")
status = svm.save_serializable(fstream)
check_status(status,'h5')
fstream = SerializableAsciiFile("blaah.asc", "w")
status = svm.save_serializable(fstream)
check_status(status,'asc')
fstream = SerializableJsonFile("blaah.json", "w")
status = svm.save_serializable(fstream)
check_status(status,'json')
fstream = SerializableXmlFile("blaah.xml", "w")
status = svm.save_serializable(fstream)
check_status(status,'xml')
fstream = SerializableHdf5File("blaah.h5", "r")
new_svm=GMNPSVM()
status = new_svm.load_serializable(fstream)
check_status(status,'h5')
new_svm.train()
bias_h5 = new_svm.get_svm(0).get_bias()
fstream = SerializableAsciiFile("blaah.asc", "r")
new_svm=GMNPSVM()
status = new_svm.load_serializable(fstream)
check_status(status,'asc')
new_svm.train()
bias_asc = new_svm.get_svm(0).get_bias()
fstream = SerializableJsonFile("blaah.json", "r")
new_svm=GMNPSVM()
status = new_svm.load_serializable(fstream)
check_status(status,'json')
new_svm.train()
bias_json = new_svm.get_svm(0).get_bias()
fstream = SerializableXmlFile("blaah.xml", "r")
new_svm=GMNPSVM()
status = new_svm.load_serializable(fstream)
check_status(status,'xml')
new_svm.train()
bias_xml = new_svm.get_svm(0).get_bias()
os.unlink("blaah.h5")
os.unlink("blaah.asc")
os.unlink("blaah.json")
os.unlink("blaah.xml")
return svm,new_svm, bias_ref, bias_h5, bias_asc, bias_json, bias_xml
def modelselection_grid_search_libsvr_modular (fm_train=traindat,fm_test=testdat,label_train=label_traindat,\
width=2.1,C=1,epsilon=1e-5,tube_epsilon=1e-2):
from modshogun import CrossValidation, CrossValidationResult
from modshogun import MeanSquaredError
from modshogun import CrossValidationSplitting
from modshogun import RegressionLabels
from modshogun import RealFeatures
from modshogun import GaussianKernel
from modshogun import LibSVR
from modshogun import GridSearchModelSelection
from modshogun import ModelSelectionParameters, R_EXP
from modshogun import ParameterCombination
# training data
features_train = RealFeatures(traindat)
labels = RegressionLabels(label_traindat)
# kernel
kernel = GaussianKernel(features_train, features_train, width)
# print all parameter available for modelselection
# Dont worry if yours is not included but, write to the mailing list
#kernel.print_modsel_params()
labels = RegressionLabels(label_train)
# predictor
predictor = LibSVR(C, tube_epsilon, kernel, labels)
predictor.set_epsilon(epsilon)
# splitting strategy for 5 fold cross-validation (for classification its better
# to use "StratifiedCrossValidation", but the standard
# "StratifiedCrossValidationSplitting" is also available
splitting_strategy = CrossValidationSplitting(labels, 5)
# evaluation method
evaluation_criterium = MeanSquaredError()
# cross-validation instance
cross_validation = CrossValidation(predictor, features_train, labels,
splitting_strategy,
evaluation_criterium)
# (optional) repeat x-val (set larger to get better estimates, at least two
# for confidence intervals)
cross_validation.set_num_runs(2)
# (optional) request 95% confidence intervals for results (not actually
# needed for this toy example)
cross_validation.set_conf_int_alpha(0.05)
# print all parameter available for modelselection
# Dont worry if yours is not included but, write to the mailing list
#predictor.print_modsel_params()
# build parameter tree to select C1 and C2
param_tree_root = ModelSelectionParameters()
c1 = ModelSelectionParameters("C1")
param_tree_root.append_child(c1)
c1.build_values(-1.0, 0.0, R_EXP)
c2 = ModelSelectionParameters("C2")
param_tree_root.append_child(c2)
c2.build_values(-1.0, 0.0, R_EXP)
# model selection instance
model_selection = GridSearchModelSelection(cross_validation,
param_tree_root)
# perform model selection with selected methods
#print "performing model selection of"
#print "parameter tree"
#param_tree_root.print_tree()
#print "starting model selection"
# print the current parameter combination, if no parameter nothing is printed
print_state = False
# lock data before since model selection will not change the kernel matrix
# (use with care) This avoids that the kernel matrix is recomputed in every
# iteration of the model search
predictor.data_lock(labels, features_train)
best_parameters = model_selection.select_model(print_state)
# print best parameters
#print "best parameters:"
#best_parameters.print_tree()
# apply them and print result
best_parameters.apply_to_machine(predictor)
result = cross_validation.evaluate()
def evaluation_cross_validation_multiclass_storage (traindat=traindat, label_traindat=label_traindat):
from modshogun import CrossValidation, CrossValidationResult
from modshogun import CrossValidationPrintOutput
from modshogun import CrossValidationMKLStorage, CrossValidationMulticlassStorage
from modshogun import MulticlassAccuracy, F1Measure
from modshogun import StratifiedCrossValidationSplitting
from modshogun import MulticlassLabels
from modshogun import RealFeatures, CombinedFeatures
from modshogun import GaussianKernel, CombinedKernel
from modshogun import MKLMulticlass
from modshogun import Statistics, MSG_DEBUG, Math
Math.init_random(1)
# training data, combined features all on same data
features=RealFeatures(traindat)
comb_features=CombinedFeatures()
comb_features.append_feature_obj(features)
comb_features.append_feature_obj(features)
comb_features.append_feature_obj(features)
labels=MulticlassLabels(label_traindat)
# kernel, different Gaussians combined
kernel=CombinedKernel()
kernel.append_kernel(GaussianKernel(10, 0.1))
kernel.append_kernel(GaussianKernel(10, 1))
kernel.append_kernel(GaussianKernel(10, 2))
# create mkl using libsvm, due to a mem-bug, interleaved is not possible
svm=MKLMulticlass(1.0,kernel,labels);
svm.set_kernel(kernel);
# splitting strategy for 5 fold cross-validation (for classification its better
# to use "StratifiedCrossValidation", but the standard
# "StratifiedCrossValidationSplitting" is also available
splitting_strategy=StratifiedCrossValidationSplitting(labels, 3)
# evaluation method
evaluation_criterium=MulticlassAccuracy()
# cross-validation instance
cross_validation=CrossValidation(svm, comb_features, labels,
splitting_strategy, evaluation_criterium)
cross_validation.set_autolock(False)
# append cross vlaidation output classes
#cross_validation.add_cross_validation_output(CrossValidationPrintOutput())
#mkl_storage=CrossValidationMKLStorage()
#cross_validation.add_cross_validation_output(mkl_storage)
multiclass_storage=CrossValidationMulticlassStorage()
multiclass_storage.append_binary_evaluation(F1Measure())
cross_validation.add_cross_validation_output(multiclass_storage)
cross_validation.set_num_runs(3)
# perform cross-validation
result=cross_validation.evaluate()
roc_0_0_0 = multiclass_storage.get_fold_ROC(0,0,0)
#print roc_0_0_0
auc_0_0_0 = multiclass_storage.get_fold_evaluation_result(0,0,0,0)
#print auc_0_0_0
return roc_0_0_0, auc_0_0_0
def statistics_linear_time_mmd(n, dim, difference):
from modshogun import RealFeatures
from modshogun import MeanShiftDataGenerator
from modshogun import GaussianKernel
from modshogun import LinearTimeMMD
from modshogun import PERMUTATION, MMD1_GAUSSIAN
from modshogun import EuclideanDistance
from modshogun import Statistics, Math
# init seed for reproducability
Math.init_random(1)
# note that the linear time statistic is designed for much larger datasets
# so increase to get reasonable results
# streaming data generator for mean shift distributions
gen_p = MeanShiftDataGenerator(0, dim)
gen_q = MeanShiftDataGenerator(difference, dim)
# compute median data distance in order to use for Gaussian kernel width
# 0.5*median_distance normally (factor two in Gaussian kernel)
# However, shoguns kernel width is different to usual parametrization
# Therefore 0.5*2*median_distance^2
# Use a subset of data for that, only 200 elements. Median is stable
# Stream examples and merge them in order to compute median on joint sample
features = gen_p.get_streamed_features(100)
features = features.create_merged_copy(gen_q.get_streamed_features(100))
# compute all pairwise distances
dist = EuclideanDistance(features, features)
distances = dist.get_distance_matrix()
# compute median and determine kernel width (using shogun)
median_distance = Statistics.matrix_median(distances, True)
sigma = median_distance**2
#print "median distance for Gaussian kernel:", sigma
kernel = GaussianKernel(10, sigma)
# mmd instance using streaming features, blocksize of 10000
mmd = LinearTimeMMD(kernel, gen_p, gen_q, n, 10000)
# perform test: compute p-value and test if null-hypothesis is rejected for
# a test level of 0.05
statistic = mmd.compute_statistic()
#print "test statistic:", statistic
# do the same thing using two different way to approximate null-dstribution
# sampling null and gaussian approximation (ony for really large samples)
alpha = 0.05
#print "computing p-value using sampling null"
mmd.set_null_approximation_method(PERMUTATION)
mmd.set_num_null_samples(50) # normally, far more iterations are needed
p_value_boot = mmd.compute_p_value(statistic)
#print "p_value_boot:", p_value_boot
#print "p_value_boot <", alpha, ", i.e. test sais p!=q:", p_value_boot<alpha
#print "computing p-value using gaussian approximation"
mmd.set_null_approximation_method(MMD1_GAUSSIAN)
p_value_gaussian = mmd.compute_p_value(statistic)
#print "p_value_gaussian:", p_value_gaussian
#print "p_value_gaussian <", alpha, ", i.e. test sais p!=q:", p_value_gaussian<alpha
# sample from null distribution (these may be plotted or whatsoever)
# mean should be close to zero, variance stronly depends on data/kernel
mmd.set_null_approximation_method(PERMUTATION)
mmd.set_num_null_samples(10) # normally, far more iterations are needed
null_samples = mmd.sample_null()
#print "null mean:", mean(null_samples)
#print "null variance:", var(null_samples)
# compute type I and type II errors for Gaussian approximation
# number of trials should be larger to compute tight confidence bounds
mmd.set_null_approximation_method(MMD1_GAUSSIAN)
num_trials = 5
alpha = 0.05 # test power
typeIerrors = [0 for x in range(num_trials)]
typeIIerrors = [0 for x in range(num_trials)]
for i in range(num_trials):
# this effectively means that p=q - rejecting is tpye I error
mmd.set_simulate_h0(True)
typeIerrors[i] = mmd.perform_test() > alpha
mmd.set_simulate_h0(False)
typeIIerrors[i] = mmd.perform_test() > alpha
#print "type I error:", mean(typeIerrors), ", type II error:", mean(typeIIerrors)
return statistic, p_value_boot, p_value_gaussian, null_samples, typeIerrors, typeIIerrors
def RunKPCAShogun(q):
totalTimer = Timer()
try:
# Load input dataset.
Log.Info("Loading dataset", self.verbose)
data = np.genfromtxt(self.dataset, delimiter=',')
dataFeat = RealFeatures(data.T)
with totalTimer:
# Get the new dimensionality, if it is necessary.
if "new_dimensionality" in options:
d = int(options.pop("new_dimensionality"))
if (d > data.shape[1]):
Log.Fatal("New dimensionality (" + str(d) +
") cannot be greater " +
"than existing dimensionality (" +
str(data.shape[1]) + ")!")
q.put(-1)
return -1
else:
d = data.shape[1]
# Get the kernel type and make sure it is valid.
if "kernel" in options:
kernel = str(options.pop("kernel"))
else:
Log.Fatal(
"Choose kernel type, valid choices are 'linear'," +
" 'hyptan', 'polynomial' and 'gaussian'.")
q.put(-1)
return -1
if "degree" in options:
degree = int(options.pop("degree"))
if len(options) > 0:
Log.Fatal("Unknown parameters: " + str(options))
raise Exception("unknown parameters")
if kernel == "polynomial":
kernel = PolyKernel(dataFeat, dataFeat, degree, True)
elif kernel == "gaussian":
kernel = GaussianKernel(dataFeat, dataFeat, 2.0)
elif kernel == "linear":
kernel = LinearKernel(dataFeat, dataFeat)
elif kernel == "hyptan":
kernel = SigmoidKernel(dataFeat, dataFeat, 2, 1.0, 1.0)
else:
Log.Fatal(
"Invalid kernel type (" + kernel.group(1) +
"); valid " +
"choices are 'linear', 'hyptan', 'polynomial' and 'gaussian'."
)
q.put(-1)
return -1
# Perform Kernel Principal Components Analysis.
model = KernelPCA(kernel)
model.set_target_dim(d)
model.init(dataFeat)
model.apply_to_feature_matrix(dataFeat)
except Exception as e:
q.put(-1)
return -1
time = totalTimer.ElapsedTime()
q.put(time)
return time
def predict_new_data(graph_file, cons_file, tri_file, other_feature_file):
print 'reading extracted features'
graph_feature = read_feature_data(graph_file)
graph_feature = get_normalized_given_max_min(graph_feature,
'models/grtaph_max_size')
cons_feature = read_feature_data(cons_file)
cons_feature = get_normalized_given_max_min(cons_feature,
'models/cons_max_size')
CC_feature = read_feature_data(tri_file)
CC_feature = get_normalized_given_max_min(CC_feature,
'models/tri_max_size')
ATOS_feature = read_feature_data(other_feature_file)
ATOS_feature = get_normalized_given_max_min(ATOS_feature,
'models/alu_max_size')
width, C, epsilon, num_threads, mkl_epsilon, mkl_norm = 0.5, 1.2, 1e-5, 1, 0.001, 3.5
kernel = CombinedKernel()
feats_train = CombinedFeatures()
feats_test = CombinedFeatures()
#pdb.set_trace()
subkfeats_train = RealFeatures()
subkfeats_test = RealFeatures(np.transpose(np.array(graph_feature)))
subkernel = GaussianKernel(10, width)
feats_test.append_feature_obj(subkfeats_test)
fstream = SerializableAsciiFile("models/graph.dat", "r")
status = subkfeats_train.load_serializable(fstream)
feats_train.append_feature_obj(subkfeats_train)
kernel.append_kernel(subkernel)
subkfeats_train = RealFeatures()
subkfeats_test = RealFeatures(np.transpose(np.array(cons_feature)))
subkernel = GaussianKernel(10, width)
feats_test.append_feature_obj(subkfeats_test)
fstream = SerializableAsciiFile("models/cons.dat", "r")
status = subkfeats_train.load_serializable(fstream)
feats_train.append_feature_obj(subkfeats_train)
kernel.append_kernel(subkernel)
subkfeats_train = RealFeatures()
subkfeats_test = RealFeatures(np.transpose(np.array(CC_feature)))
subkernel = GaussianKernel(10, width)
feats_test.append_feature_obj(subkfeats_test)
fstream = SerializableAsciiFile("models/tri.dat", "r")
status = subkfeats_train.load_serializable(fstream)
feats_train.append_feature_obj(subkfeats_train)
kernel.append_kernel(subkernel)
subkfeats_train = RealFeatures()
subkfeats_test = RealFeatures(np.transpose(np.array(ATOS_feature)))
subkernel = GaussianKernel(10, width)
feats_test.append_feature_obj(subkfeats_test)
fstream = SerializableAsciiFile("models/alu.dat", "r")
status = subkfeats_train.load_serializable(fstream)
feats_train.append_feature_obj(subkfeats_train)
kernel.append_kernel(subkernel)
model_file = "models/mkl.dat"
if not os.path.exists(model_file):
print 'downloading model file'
url_add = 'http://rth.dk/resources/mirnasponge/data/mkl.dat'
urllib.urlretrieve(url_add, model_file)
print 'loading trained model'
fstream = SerializableAsciiFile("models/mkl.dat", "r")
new_mkl = MKLClassification()
status = new_mkl.load_serializable(fstream)
print 'model predicting'
kernel.init(feats_train, feats_test)
new_mkl.set_kernel(kernel)
y_out = new_mkl.apply().get_labels()
return y_out
# of the authors and should not be interpreted as representing official policies,
# either expressed or implied, of the Shogun Development Team.
import argparse
import logging
from contextlib import contextmanager, closing
from modshogun import (LibSVMFile, GaussianKernel, MulticlassLibSVM,
SerializableHdf5File, LinearKernel)
from utils import get_features_and_labels, track_execution
LOGGER = logging.getLogger(__file__)
KERNELS = {
'linear': lambda feats, width: LinearKernel(feats, feats),
'gaussian': lambda feats, width: GaussianKernel(feats, feats, width),
}
def parse_arguments():
parser = argparse.ArgumentParser(description="Train a multiclass SVM \
stored in libsvm format")
parser.add_argument('--dataset', required=True, type=str,
help='Path to training dataset in LibSVM format.')
parser.add_argument('--capacity', default=1.0, type=float,
help='SVM capacity parameter')
parser.add_argument('--width', default=2.1, type=float,
help='Width of the Gaussian Kernel to approximate')
parser.add_argument('--epsilon', default=0.01, type=float,
help='SVMOcas epsilon parameter')
parser.add_argument('--kernel', type=str, default='linear',
choices=['linear', 'gaussian'],
def linear_time_mmd_graphical():
# parameters, change to get different results
m=1000 # set to 10000 for a good test result
dim=2
# setting the difference of the first dimension smaller makes a harder test
difference=1
# number of samples taken from null and alternative distribution
num_null_samples=150
# streaming data generator for mean shift distributions
gen_p=MeanShiftDataGenerator(0, dim)
gen_q=MeanShiftDataGenerator(difference, dim)
# use the median kernel selection
# create combined kernel with Gaussian kernels inside (shoguns Gaussian kernel is
# compute median data distance in order to use for Gaussian kernel width
# 0.5*median_distance normally (factor two in Gaussian kernel)
# However, shoguns kernel width is different to usual parametrization
# Therefore 0.5*2*median_distance^2
# Use a subset of data for that, only 200 elements. Median is stable
sigmas=[2**x for x in range(-3,10)]
widths=[x*x*2 for x in sigmas]
print "kernel widths:", widths
combined=CombinedKernel()
for i in range(len(sigmas)):
combined.append_kernel(GaussianKernel(10, widths[i]))
# mmd instance using streaming features, blocksize of 10000
block_size=1000
mmd=LinearTimeMMD(combined, gen_p, gen_q, m, block_size)
# kernel selection instance (this can easily replaced by the other methods for selecting
# single kernels
selection=MMDKernelSelectionOpt(mmd)
# perform kernel selection
kernel=selection.select_kernel()
kernel=GaussianKernel.obtain_from_generic(kernel)
mmd.set_kernel(kernel);
print "selected kernel width:", kernel.get_width()
# sample alternative distribution, stream ensures different samples each run
alt_samples=zeros(num_null_samples)
for i in range(len(alt_samples)):
alt_samples[i]=mmd.compute_statistic()
# sample from null distribution
# bootstrapping, biased statistic
mmd.set_null_approximation_method(PERMUTATION)
mmd.set_num_null_samples(num_null_samples)
null_samples_boot=mmd.sample_null()
# fit normal distribution to null and sample a normal distribution
mmd.set_null_approximation_method(MMD1_GAUSSIAN)
variance=mmd.compute_variance_estimate()
null_samples_gaussian=normal(0,sqrt(variance),num_null_samples)
# to plot data, sample a few examples from stream first
features=gen_p.get_streamed_features(m)
features=features.create_merged_copy(gen_q.get_streamed_features(m))
data=features.get_feature_matrix()
# plot
figure()
# plot data of p and q
subplot(2,3,1)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 4) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 4) ) # reduce number of x-ticks
plot(data[0][0:m], data[1][0:m], 'ro', label='$x$')
plot(data[0][m+1:2*m], data[1][m+1:2*m], 'bo', label='$x$', alpha=0.5)
title('Data, shift in $x_1$='+str(difference)+'\nm='+str(m))
xlabel('$x_1, y_1$')
ylabel('$x_2, y_2$')
# histogram of first data dimension and pdf
subplot(2,3,2)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
hist(data[0], bins=50, alpha=0.5, facecolor='r', normed=True)
hist(data[1], bins=50, alpha=0.5, facecolor='b', normed=True)
xs=linspace(min(data[0])-1,max(data[0])+1, 50)
plot(xs,normpdf( xs, 0, 1), 'r', linewidth=3)
plot(xs,normpdf( xs, difference, 1), 'b', linewidth=3)
xlabel('$x_1, y_1$')
ylabel('$p(x_1), p(y_1)$')
title('Data PDF in $x_1, y_1$')
# compute threshold for test level
alpha=0.05
null_samples_boot.sort()
null_samples_gaussian.sort()
thresh_boot=null_samples_boot[floor(len(null_samples_boot)*(1-alpha))];
thresh_gaussian=null_samples_gaussian[floor(len(null_samples_gaussian)*(1-alpha))];
type_one_error_boot=sum(null_samples_boot<thresh_boot)/float(num_null_samples)
type_one_error_gaussian=sum(null_samples_gaussian<thresh_boot)/float(num_null_samples)
# plot alternative distribution with threshold
subplot(2,3,4)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
hist(alt_samples, 20, normed=True);
axvline(thresh_boot, 0, 1, linewidth=2, color='red')
type_two_error=sum(alt_samples<thresh_boot)/float(num_null_samples)
title('Alternative Dist.\n' + 'Type II error is ' + str(type_two_error))
# compute range for all null distribution histograms
hist_range=[min([min(null_samples_boot), min(null_samples_gaussian)]), max([max(null_samples_boot), max(null_samples_gaussian)])]
# plot null distribution with threshold
subplot(2,3,3)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
hist(null_samples_boot, 20, range=hist_range, normed=True);
axvline(thresh_boot, 0, 1, linewidth=2, color='red')
title('Sampled Null Dist.\n' + 'Type I error is ' + str(type_one_error_boot))
# plot null distribution gaussian
subplot(2,3,5)
grid(True)
gca().xaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
gca().yaxis.set_major_locator( MaxNLocator(nbins = 3) ) # reduce number of x-ticks
hist(null_samples_gaussian, 20, range=hist_range, normed=True);
axvline(thresh_gaussian, 0, 1, linewidth=2, color='red')
title('Null Dist. Gaussian\nType I error is ' + str(type_one_error_gaussian))
# pull plots a bit apart
subplots_adjust(hspace=0.5)
subplots_adjust(wspace=0.5)
def gaussian_process_binary_classification_laplace(X_train,
y_train,
n_test=50):
# import all necessary modules from Shogun (some of them require Eigen3)
try:
from modshogun import RealFeatures, BinaryLabels, GaussianKernel, \
LogitLikelihood, ProbitLikelihood, ZeroMean, LaplacianInferenceMethod, \
EPInferenceMethod, GaussianProcessClassification
except ImportError:
print('Eigen3 needed for Gaussian Processes')
return
# convert training data into Shogun representation
train_features = RealFeatures(X_train)
train_labels = BinaryLabels(y_train)
# generate all pairs in 2d range of testing data
x1 = linspace(X_train[0, :].min() - 1, X_train[0, :].max() + 1, n_test)
x2 = linspace(X_train[1, :].min() - 1, X_train[1, :].max() + 1, n_test)
X_test = asarray(list(product(x1, x2))).T
# convert testing features into Shogun representation
test_features = RealFeatures(X_test)
# create Gaussian kernel with width = 2.0
kernel = GaussianKernel(10, 2.0)
# create zero mean function
mean = ZeroMean()
# you can easily switch between probit and logit likelihood models
# by uncommenting/commenting the following lines:
# create probit likelihood model
# lik = ProbitLikelihood()
# create logit likelihood model
lik = LogitLikelihood()
# you can easily switch between Laplace and EP approximation by
# uncommenting/commenting the following lines:
# specify Laplace approximation inference method
# inf = LaplacianInferenceMethod(kernel, train_features, mean, train_labels, lik)
# specify EP approximation inference method
inf = EPInferenceMethod(kernel, train_features, mean, train_labels, lik)
# create and train GP classifier, which uses Laplace approximation
gp = GaussianProcessClassification(inf)
gp.train()
# get probabilities p(y*=1|x*) for each testing feature x*
p_test = gp.get_probabilities(test_features)
# create figure
figure()
title('Training examples, predictive probability and decision boundary')
# plot training data
plot(X_train[0, argwhere(y_train == 1)], X_train[1,
argwhere(y_train == 1)],
'ro')
plot(X_train[0, argwhere(y_train == -1)], X_train[1,
argwhere(y_train == -1)],
'bo')
# plot decision boundary
contour(x1,
x2,
reshape(p_test, (n_test, n_test)),
levels=[0.5],
colors=('black'))
# plot probabilities
pcolor(x1, x2, reshape(p_test, (n_test, n_test)))
# show color bar
colorbar()
# show figure
show()
def statistics_hsic(n, difference, angle):
from modshogun import RealFeatures
from modshogun import DataGenerator
from modshogun import GaussianKernel
from modshogun import HSIC
from modshogun import PERMUTATION, HSIC_GAMMA
from modshogun import EuclideanDistance
from modshogun import Statistics, Math
# for reproducable results (the numpy one might not be reproducible across
# different OS/Python-distributions
Math.init_random(1)
np.random.seed(1)
# note that the HSIC has to store kernel matrices
# which upper bounds the sample size
# use data generator class to produce example data
data = DataGenerator.generate_sym_mix_gauss(n, difference, angle)
#plot(data[0], data[1], 'x');show()
# create shogun feature representation
features_x = RealFeatures(np.array([data[0]]))
features_y = RealFeatures(np.array([data[1]]))
# compute median data distance in order to use for Gaussian kernel width
# 0.5*median_distance normally (factor two in Gaussian kernel)
# However, shoguns kernel width is different to usual parametrization
# Therefore 0.5*2*median_distance^2
# Use a subset of data for that, only 200 elements. Median is stable
subset = np.random.permutation(features_x.get_num_vectors()).astype(
np.int32)
subset = subset[0:200]
features_x.add_subset(subset)
dist = EuclideanDistance(features_x, features_x)
distances = dist.get_distance_matrix()
features_x.remove_subset()
median_distance = np.median(distances)
sigma_x = median_distance**2
features_y.add_subset(subset)
dist = EuclideanDistance(features_y, features_y)
distances = dist.get_distance_matrix()
features_y.remove_subset()
median_distance = np.median(distances)
sigma_y = median_distance**2
#print "median distance for Gaussian kernel on x:", sigma_x
#print "median distance for Gaussian kernel on y:", sigma_y
kernel_x = GaussianKernel(10, sigma_x)
kernel_y = GaussianKernel(10, sigma_y)
hsic = HSIC(kernel_x, kernel_y, features_x, features_y)
# perform test: compute p-value and test if null-hypothesis is rejected for
# a test level of 0.05 using different methods to approximate
# null-distribution
statistic = hsic.compute_statistic()
#print "HSIC:", statistic
alpha = 0.05
#print "computing p-value using sampling null"
hsic.set_null_approximation_method(PERMUTATION)
# normally, at least 250 iterations should be done, but that takes long
hsic.set_num_null_samples(100)
# sampling null allows usage of unbiased or biased statistic
p_value_boot = hsic.compute_p_value(statistic)
thresh_boot = hsic.compute_threshold(alpha)
#print "p_value:", p_value_boot
#print "threshold for 0.05 alpha:", thresh_boot
#print "p_value <", alpha, ", i.e. test sais p and q are dependend:", p_value_boot<alpha
#print "computing p-value using gamma method"
hsic.set_null_approximation_method(HSIC_GAMMA)
p_value_gamma = hsic.compute_p_value(statistic)
thresh_gamma = hsic.compute_threshold(alpha)
#print "p_value:", p_value_gamma
#print "threshold for 0.05 alpha:", thresh_gamma
#print "p_value <", alpha, ", i.e. test sais p and q are dependend:", p_value_gamma<alpha
# sample from null distribution (these may be plotted or whatsoever)
# mean should be close to zero, variance stronly depends on data/kernel
# sampling null, biased statistic
#print "sampling null distribution using sample_null"
hsic.set_null_approximation_method(PERMUTATION)
hsic.set_num_null_samples(100)
null_samples = hsic.sample_null()
#print "null mean:", np.mean(null_samples)
#print "null variance:", np.var(null_samples)
#hist(null_samples, 100); show()
return p_value_boot, thresh_boot, p_value_gamma, thresh_gamma, statistic, null_samples
def statistics_mmd_kernel_selection_single(m,distance,stretch,num_blobs,angle,selection_method):
from modshogun import RealFeatures
from modshogun import GaussianBlobsDataGenerator
from modshogun import GaussianKernel, CombinedKernel
from modshogun import LinearTimeMMD
from modshogun import MMDKernelSelectionMedian
from modshogun import MMDKernelSelectionMax
from modshogun import MMDKernelSelectionOpt
from modshogun import PERMUTATION, MMD1_GAUSSIAN
from modshogun import EuclideanDistance
from modshogun import Statistics, Math
# init seed for reproducability
Math.init_random(1)
# note that the linear time statistic is designed for much larger datasets
# results for this low number will be bad (unstable, type I error wrong)
m=1000
distance=10
stretch=5
num_blobs=3
angle=pi/4
# streaming data generator
gen_p=GaussianBlobsDataGenerator(num_blobs, distance, 1, 0)
gen_q=GaussianBlobsDataGenerator(num_blobs, distance, stretch, angle)
# stream some data and plot
num_plot=1000
features=gen_p.get_streamed_features(num_plot)
features=features.create_merged_copy(gen_q.get_streamed_features(num_plot))
data=features.get_feature_matrix()
#figure()
#subplot(2,2,1)
#grid(True)
#plot(data[0][0:num_plot], data[1][0:num_plot], 'r.', label='$x$')
#title('$X\sim p$')
#subplot(2,2,2)
#grid(True)
#plot(data[0][num_plot+1:2*num_plot], data[1][num_plot+1:2*num_plot], 'b.', label='$x$', alpha=0.5)
#title('$Y\sim q$')
# create combined kernel with Gaussian kernels inside (shoguns Gaussian kernel is
# different to the standard form, see documentation)
sigmas=[2**x for x in range(-3,10)]
widths=[x*x*2 for x in sigmas]
combined=CombinedKernel()
for i in range(len(sigmas)):
combined.append_kernel(GaussianKernel(10, widths[i]))
# mmd instance using streaming features, blocksize of 10000
block_size=1000
mmd=LinearTimeMMD(combined, gen_p, gen_q, m, block_size)
# kernel selection instance (this can easily replaced by the other methods for selecting
# single kernels
if selection_method=="opt":
selection=MMDKernelSelectionOpt(mmd)
elif selection_method=="max":
selection=MMDKernelSelectionMax(mmd)
elif selection_method=="median":
selection=MMDKernelSelectionMedian(mmd)
# print measures (just for information)
# in case Opt: ratios of MMD and standard deviation
# in case Max: MMDs for each kernel
# Does not work for median method
if selection_method!="median":
ratios=selection.compute_measures()
#print "Measures:", ratios
#subplot(2,2,3)
#plot(ratios)
#title('Measures')
# perform kernel selection
kernel=selection.select_kernel()
kernel=GaussianKernel.obtain_from_generic(kernel)
#print "selected kernel width:", kernel.get_width()
# compute tpye I and II error (use many more trials). Type I error is only
# estimated to check MMD1_GAUSSIAN method for estimating the null
# distribution. Note that testing has to happen on difference data than
# kernel selecting, but the linear time mmd does this implicitly
mmd.set_kernel(kernel)
mmd.set_null_approximation_method(MMD1_GAUSSIAN)
# number of trials should be larger to compute tight confidence bounds
num_trials=5;
alpha=0.05 # test power
typeIerrors=[0 for x in range(num_trials)]
typeIIerrors=[0 for x in range(num_trials)]
for i in range(num_trials):
# this effectively means that p=q - rejecting is tpye I error
mmd.set_simulate_h0(True)
typeIerrors[i]=mmd.perform_test()>alpha
mmd.set_simulate_h0(False)
typeIIerrors[i]=mmd.perform_test()>alpha
#print "type I error:", mean(typeIerrors), ", type II error:", mean(typeIIerrors)
return kernel,typeIerrors,typeIIerrors
def modelselection_parameter_tree_modular(dummy):
from modshogun import ParameterCombination
from modshogun import ModelSelectionParameters, R_EXP, R_LINEAR
from modshogun import PowerKernel
from modshogun import GaussianKernel
from modshogun import DistantSegmentsKernel
from modshogun import MinkowskiMetric
root = ModelSelectionParameters()
combinations = root.get_combinations()
combinations.get_num_elements()
c = ModelSelectionParameters('C')
root.append_child(c)
c.build_values(1, 11, R_EXP)
power_kernel = PowerKernel()
# print all parameter available for modelselection
# Dont worry if yours is not included but, write to the mailing list
#power_kernel.print_modsel_params()
param_power_kernel = ModelSelectionParameters('kernel', power_kernel)
root.append_child(param_power_kernel)
param_power_kernel_degree = ModelSelectionParameters('degree')
param_power_kernel_degree.build_values(1, 1, R_EXP)
param_power_kernel.append_child(param_power_kernel_degree)
metric1 = MinkowskiMetric(10)
# print all parameter available for modelselection
# Dont worry if yours is not included but, write to the mailing list
#metric1.print_modsel_params()
param_power_kernel_metric1 = ModelSelectionParameters('distance', metric1)
param_power_kernel.append_child(param_power_kernel_metric1)
param_power_kernel_metric1_k = ModelSelectionParameters('k')
param_power_kernel_metric1_k.build_values(1, 12, R_LINEAR)
param_power_kernel_metric1.append_child(param_power_kernel_metric1_k)
gaussian_kernel = GaussianKernel()
# print all parameter available for modelselection
# Dont worry if yours is not included but, write to the mailing list
#gaussian_kernel.print_modsel_params()
param_gaussian_kernel = ModelSelectionParameters('kernel', gaussian_kernel)
root.append_child(param_gaussian_kernel)
param_gaussian_kernel_width = ModelSelectionParameters('width')
param_gaussian_kernel_width.build_values(1, 2, R_EXP)
param_gaussian_kernel.append_child(param_gaussian_kernel_width)
ds_kernel = DistantSegmentsKernel()
# print all parameter available for modelselection
# Dont worry if yours is not included but, write to the mailing list
#ds_kernel.print_modsel_params()
param_ds_kernel = ModelSelectionParameters('kernel', ds_kernel)
root.append_child(param_ds_kernel)
param_ds_kernel_delta = ModelSelectionParameters('delta')
param_ds_kernel_delta.build_values(1, 2, R_EXP)
param_ds_kernel.append_child(param_ds_kernel_delta)
param_ds_kernel_theta = ModelSelectionParameters('theta')
param_ds_kernel_theta.build_values(1, 2, R_EXP)
param_ds_kernel.append_child(param_ds_kernel_theta)
# root.print_tree()
combinations = root.get_combinations()
# for i in range(combinations.get_num_elements()):
# combinations.get_element(i).print_tree()
return
def statistics_quadratic_time_mmd(m, dim, difference):
from modshogun import RealFeatures
from modshogun import MeanShiftDataGenerator
from modshogun import GaussianKernel, CustomKernel
from modshogun import QuadraticTimeMMD
from modshogun import BOOTSTRAP, MMD2_SPECTRUM, MMD2_GAMMA, BIASED, UNBIASED
from modshogun import Statistics, IntVector, RealVector, Math
# init seed for reproducability
Math.init_random(1)
random.seed(17)
# number of examples kept low in order to make things fast
# streaming data generator for mean shift distributions
gen_p = MeanShiftDataGenerator(0, dim)
#gen_p.parallel.set_num_threads(1)
gen_q = MeanShiftDataGenerator(difference, dim)
# stream some data from generator
feat_p = gen_p.get_streamed_features(m)
feat_q = gen_q.get_streamed_features(m)
# set kernel a-priori. usually one would do some kernel selection. See
# other examples for this.
width = 10
kernel = GaussianKernel(10, width)
# create quadratic time mmd instance. Note that this constructor
# copies p and q and does not reference them
mmd = QuadraticTimeMMD(kernel, feat_p, feat_q)
# perform test: compute p-value and test if null-hypothesis is rejected for
# a test level of 0.05
alpha = 0.05
# using bootstrapping (slow, not the most reliable way. Consider pre-
# computing the kernel when using it, see below).
# Also, in practice, use at least 250 iterations
mmd.set_null_approximation_method(BOOTSTRAP)
mmd.set_bootstrap_iterations(3)
p_value_boot = mmd.perform_test()
# reject if p-value is smaller than test level
#print "bootstrap: p!=q: ", p_value_boot<alpha
# using spectrum method. Use at least 250 samples from null.
# This is consistent but sometimes breaks, always monitor type I error.
# See tutorial for number of eigenvalues to use .
# Only works with BIASED statistic
mmd.set_statistic_type(BIASED)
mmd.set_null_approximation_method(MMD2_SPECTRUM)
mmd.set_num_eigenvalues_spectrum(3)
mmd.set_num_samples_sepctrum(250)
p_value_spectrum = mmd.perform_test()
# reject if p-value is smaller than test level
#print "spectrum: p!=q: ", p_value_spectrum<alpha
# using gamma method. This is a quick hack, which works most of the time
# but is NOT guaranteed to. See tutorial for details.
# Only works with BIASED statistic
mmd.set_statistic_type(BIASED)
mmd.set_null_approximation_method(MMD2_GAMMA)
p_value_gamma = mmd.perform_test()
# reject if p-value is smaller than test level
#print "gamma: p!=q: ", p_value_gamma<alpha
# compute tpye I and II error (use many more trials in practice).
# Type I error is not necessary if one uses bootstrapping. We do it here
# anyway, but note that this is an efficient way of computing it.
# Also note that testing has to happen on
# difference data than kernel selection, but the linear time mmd does this
# implicitly and we used a fixed kernel here.
mmd.set_null_approximation_method(BOOTSTRAP)
mmd.set_bootstrap_iterations(5)
num_trials = 5
type_I_errors = RealVector(num_trials)
type_II_errors = RealVector(num_trials)
inds = int32(array([x for x in range(2 * m)])) # numpy
p_and_q = mmd.get_p_and_q()
# use a precomputed kernel to be faster
kernel.init(p_and_q, p_and_q)
precomputed = CustomKernel(kernel)
mmd.set_kernel(precomputed)
for i in range(num_trials):
# this effectively means that p=q - rejecting is tpye I error
inds = random.permutation(inds) # numpy permutation
precomputed.add_row_subset(inds)
precomputed.add_col_subset(inds)
type_I_errors[i] = mmd.perform_test() > alpha
precomputed.remove_row_subset()
precomputed.remove_col_subset()
# on normal data, this gives type II error
type_II_errors[i] = mmd.perform_test() > alpha
return type_I_errors.get(), type_I_errors.get(
), p_value_boot, p_value_spectrum, p_value_gamma,
def quadratic_time_mmd_graphical():
# parameters, change to get different results
m = 100
dim = 2
# setting the difference of the first dimension smaller makes a harder test
difference = 0.5
# number of samples taken from null and alternative distribution
num_null_samples = 500
# streaming data generator for mean shift distributions
gen_p = MeanShiftDataGenerator(0, dim)
gen_q = MeanShiftDataGenerator(difference, dim)
# Stream examples and merge them in order to compute MMD on joint sample
# alternative is to call a different constructor of QuadraticTimeMMD
features = gen_p.get_streamed_features(m)
features = features.create_merged_copy(gen_q.get_streamed_features(m))
# use the median kernel selection
# create combined kernel with Gaussian kernels inside (shoguns Gaussian kernel is
# compute median data distance in order to use for Gaussian kernel width
# 0.5*median_distance normally (factor two in Gaussian kernel)
# However, shoguns kernel width is different to usual parametrization
# Therefore 0.5*2*median_distance^2
# Use a subset of data for that, only 200 elements. Median is stable
sigmas = [2**x for x in range(-3, 10)]
widths = [x * x * 2 for x in sigmas]
print "kernel widths:", widths
combined = CombinedKernel()
for i in range(len(sigmas)):
combined.append_kernel(GaussianKernel(10, widths[i]))
# create MMD instance, use biased statistic
mmd = QuadraticTimeMMD(combined, features, m)
mmd.set_statistic_type(BIASED)
# kernel selection instance (this can easily replaced by the other methods for selecting
# single kernels
selection = MMDKernelSelectionMax(mmd)
# perform kernel selection
kernel = selection.select_kernel()
kernel = GaussianKernel.obtain_from_generic(kernel)
mmd.set_kernel(kernel)
print "selected kernel width:", kernel.get_width()
# sample alternative distribution (new data each trial)
alt_samples = zeros(num_null_samples)
for i in range(len(alt_samples)):
# Stream examples and merge them in order to replace in MMD
features = gen_p.get_streamed_features(m)
features = features.create_merged_copy(gen_q.get_streamed_features(m))
mmd.set_p_and_q(features)
alt_samples[i] = mmd.compute_statistic()
# sample from null distribution
# bootstrapping, biased statistic
mmd.set_null_approximation_method(BOOTSTRAP)
mmd.set_statistic_type(BIASED)
mmd.set_bootstrap_iterations(num_null_samples)
null_samples_boot = mmd.bootstrap_null()
# sample from null distribution
# spectrum, biased statistic
if "sample_null_spectrum" in dir(QuadraticTimeMMD):
mmd.set_null_approximation_method(MMD2_SPECTRUM)
mmd.set_statistic_type(BIASED)
null_samples_spectrum = mmd.sample_null_spectrum(
num_null_samples, m - 10)
# fit gamma distribution, biased statistic
mmd.set_null_approximation_method(MMD2_GAMMA)
mmd.set_statistic_type(BIASED)
gamma_params = mmd.fit_null_gamma()
# sample gamma with parameters
null_samples_gamma = array([
gamma(gamma_params[0], gamma_params[1])
for _ in range(num_null_samples)
])
# to plot data, sample a few examples from stream first
features = gen_p.get_streamed_features(m)
features = features.create_merged_copy(gen_q.get_streamed_features(m))
data = features.get_feature_matrix()
# plot
figure()
title('Quadratic Time MMD')
# plot data of p and q
subplot(2, 3, 1)
grid(True)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=4)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=4)) # reduce number of x-ticks
plot(data[0][0:m], data[1][0:m], 'ro', label='$x$')
plot(data[0][m + 1:2 * m],
data[1][m + 1:2 * m],
'bo',
label='$x$',
alpha=0.5)
title('Data, shift in $x_1$=' + str(difference) + '\nm=' + str(m))
xlabel('$x_1, y_1$')
ylabel('$x_2, y_2$')
# histogram of first data dimension and pdf
subplot(2, 3, 2)
grid(True)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
hist(data[0], bins=50, alpha=0.5, facecolor='r', normed=True)
hist(data[1], bins=50, alpha=0.5, facecolor='b', normed=True)
xs = linspace(min(data[0]) - 1, max(data[0]) + 1, 50)
plot(xs, normpdf(xs, 0, 1), 'r', linewidth=3)
plot(xs, normpdf(xs, difference, 1), 'b', linewidth=3)
xlabel('$x_1, y_1$')
ylabel('$p(x_1), p(y_1)$')
title('Data PDF in $x_1, y_1$')
# compute threshold for test level
alpha = 0.05
null_samples_boot.sort()
null_samples_spectrum.sort()
null_samples_gamma.sort()
thresh_boot = null_samples_boot[floor(
len(null_samples_boot) * (1 - alpha))]
thresh_spectrum = null_samples_spectrum[floor(
len(null_samples_spectrum) * (1 - alpha))]
thresh_gamma = null_samples_gamma[floor(
len(null_samples_gamma) * (1 - alpha))]
type_one_error_boot = sum(
null_samples_boot < thresh_boot) / float(num_null_samples)
type_one_error_spectrum = sum(
null_samples_spectrum < thresh_boot) / float(num_null_samples)
type_one_error_gamma = sum(
null_samples_gamma < thresh_boot) / float(num_null_samples)
# plot alternative distribution with threshold
subplot(2, 3, 4)
grid(True)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
hist(alt_samples, 20, normed=True)
axvline(thresh_boot, 0, 1, linewidth=2, color='red')
type_two_error = sum(alt_samples < thresh_boot) / float(num_null_samples)
title('Alternative Dist.\n' + 'Type II error is ' + str(type_two_error))
# compute range for all null distribution histograms
hist_range = [
min([
min(null_samples_boot),
min(null_samples_spectrum),
min(null_samples_gamma)
]),
max([
max(null_samples_boot),
max(null_samples_spectrum),
max(null_samples_gamma)
])
]
# plot null distribution with threshold
subplot(2, 3, 3)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
hist(null_samples_boot, 20, range=hist_range, normed=True)
axvline(thresh_boot, 0, 1, linewidth=2, color='red')
title('Bootstrapped Null Dist.\n' + 'Type I error is ' +
str(type_one_error_boot))
grid(True)
# plot null distribution spectrum
subplot(2, 3, 5)
grid(True)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
hist(null_samples_spectrum, 20, range=hist_range, normed=True)
axvline(thresh_spectrum, 0, 1, linewidth=2, color='red')
title('Null Dist. Spectrum\nType I error is ' +
str(type_one_error_spectrum))
# plot null distribution gamma
subplot(2, 3, 6)
grid(True)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
hist(null_samples_gamma, 20, range=hist_range, normed=True)
axvline(thresh_gamma, 0, 1, linewidth=2, color='red')
title('Null Dist. Gamma\nType I error is ' + str(type_one_error_gamma))
# pull plots a bit apart
subplots_adjust(hspace=0.5)
subplots_adjust(wspace=0.5)
def hsic_graphical():
# parameters, change to get different results
m = 250
difference = 3
# setting the angle lower makes a harder test
angle = pi / 30
# number of samples taken from null and alternative distribution
num_null_samples = 500
# use data generator class to produce example data
data = DataGenerator.generate_sym_mix_gauss(m, difference, angle)
# create shogun feature representation
features_x = RealFeatures(array([data[0]]))
features_y = RealFeatures(array([data[1]]))
# compute median data distance in order to use for Gaussian kernel width
# 0.5*median_distance normally (factor two in Gaussian kernel)
# However, shoguns kernel width is different to usual parametrization
# Therefore 0.5*2*median_distance^2
# Use a subset of data for that, only 200 elements. Median is stable
subset = int32(array([x for x in range(features_x.get_num_vectors())
])) # numpy
subset = random.permutation(subset) # numpy permutation
subset = subset[0:200]
features_x.add_subset(subset)
dist = EuclideanDistance(features_x, features_x)
distances = dist.get_distance_matrix()
features_x.remove_subset()
median_distance = Statistics.matrix_median(distances, True)
sigma_x = median_distance**2
features_y.add_subset(subset)
dist = EuclideanDistance(features_y, features_y)
distances = dist.get_distance_matrix()
features_y.remove_subset()
median_distance = Statistics.matrix_median(distances, True)
sigma_y = median_distance**2
print "median distance for Gaussian kernel on x:", sigma_x
print "median distance for Gaussian kernel on y:", sigma_y
kernel_x = GaussianKernel(10, sigma_x)
kernel_y = GaussianKernel(10, sigma_y)
# create hsic instance. Note that this is a convienience constructor which copies
# feature data. features_x and features_y are not these used in hsic.
# This is only for user-friendlyness. Usually, its ok to do this.
# Below, the alternative distribution is sampled, which means
# that new feature objects have to be created in each iteration (slow)
# However, normally, the alternative distribution is not sampled
hsic = HSIC(kernel_x, kernel_y, features_x, features_y)
# sample alternative distribution
alt_samples = zeros(num_null_samples)
for i in range(len(alt_samples)):
data = DataGenerator.generate_sym_mix_gauss(m, difference, angle)
features_x.set_feature_matrix(array([data[0]]))
features_y.set_feature_matrix(array([data[1]]))
# re-create hsic instance everytime since feature objects are copied due to
# useage of convienience constructor
hsic = HSIC(kernel_x, kernel_y, features_x, features_y)
alt_samples[i] = hsic.compute_statistic()
# sample from null distribution
# permutation, biased statistic
hsic.set_null_approximation_method(PERMUTATION)
hsic.set_num_null_samples(num_null_samples)
null_samples_boot = hsic.sample_null()
# fit gamma distribution, biased statistic
hsic.set_null_approximation_method(HSIC_GAMMA)
gamma_params = hsic.fit_null_gamma()
# sample gamma with parameters
null_samples_gamma = array([
gamma(gamma_params[0], gamma_params[1])
for _ in range(num_null_samples)
])
# plot
figure()
# plot data x and y
subplot(2, 2, 1)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=4)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=4)) # reduce number of x-ticks
grid(True)
plot(data[0], data[1], 'o')
title('Data, rotation=$\pi$/' + str(1 / angle * pi) + '\nm=' + str(m))
xlabel('$x$')
ylabel('$y$')
# compute threshold for test level
alpha = 0.05
null_samples_boot.sort()
null_samples_gamma.sort()
thresh_boot = null_samples_boot[floor(
len(null_samples_boot) * (1 - alpha))]
thresh_gamma = null_samples_gamma[floor(
len(null_samples_gamma) * (1 - alpha))]
type_one_error_boot = sum(
null_samples_boot < thresh_boot) / float(num_null_samples)
type_one_error_gamma = sum(
null_samples_gamma < thresh_boot) / float(num_null_samples)
# plot alternative distribution with threshold
subplot(2, 2, 2)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
grid(True)
hist(alt_samples, 20, normed=True)
axvline(thresh_boot, 0, 1, linewidth=2, color='red')
type_two_error = sum(alt_samples < thresh_boot) / float(num_null_samples)
title('Alternative Dist.\n' + 'Type II error is ' + str(type_two_error))
# compute range for all null distribution histograms
hist_range = [
min([min(null_samples_boot),
min(null_samples_gamma)]),
max([max(null_samples_boot),
max(null_samples_gamma)])
]
# plot null distribution with threshold
subplot(2, 2, 3)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
grid(True)
hist(null_samples_boot, 20, range=hist_range, normed=True)
axvline(thresh_boot, 0, 1, linewidth=2, color='red')
title('Sampled Null Dist.\n' + 'Type I error is ' +
str(type_one_error_boot))
# plot null distribution gamma
subplot(2, 2, 4)
gca().xaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
gca().yaxis.set_major_locator(
MaxNLocator(nbins=3)) # reduce number of x-ticks
grid(True)
hist(null_samples_gamma, 20, range=hist_range, normed=True)
axvline(thresh_gamma, 0, 1, linewidth=2, color='red')
title('Null Dist. Gamma\nType I error is ' + str(type_one_error_gamma))
grid(True)
# pull plots a bit apart
subplots_adjust(hspace=0.5)
subplots_adjust(wspace=0.5)
def RunKPCAShogun(q):
totalTimer = Timer()
try:
# Load input dataset.
Log.Info("Loading dataset", self.verbose)
data = np.genfromtxt(self.dataset, delimiter=',')
dataFeat = RealFeatures(data.T)
with totalTimer:
# Get the new dimensionality, if it is necessary.
dimension = re.search('-d (\d+)', options)
if not dimension:
d = data.shape[1]
else:
d = int(dimension.group(1))
if (d > data.shape[1]):
Log.Fatal("New dimensionality (" + str(d) +
") cannot be greater " +
"than existing dimensionality (" +
str(data.shape[1]) + ")!")
q.put(-1)
return -1
# Get the kernel type and make sure it is valid.
kernel = re.search("-k ([^\s]+)", options)
if not kernel:
Log.Fatal(
"Choose kernel type, valid choices are 'linear'," +
" 'hyptan', 'polynomial' and 'gaussian'.")
q.put(-1)
return -1
elif kernel.group(1) == "polynomial":
degree = re.search('-D (\d+)', options)
degree = 1 if not degree else int(degree.group(1))
kernel = PolyKernel(dataFeat, dataFeat, degree, True)
elif kernel.group(1) == "gaussian":
kernel = GaussianKernel(dataFeat, dataFeat, 2.0)
elif kernel.group(1) == "linear":
kernel = LinearKernel(dataFeat, dataFeat)
elif kernel.group(1) == "hyptan":
kernel = SigmoidKernel(dataFeat, dataFeat, 2, 1.0, 1.0)
else:
Log.Fatal(
"Invalid kernel type (" + kernel.group(1) +
"); valid " +
"choices are 'linear', 'hyptan', 'polynomial' and 'gaussian'."
)
q.put(-1)
return -1
# Perform Kernel Principal Components Analysis.
model = KernelPCA(kernel)
model.set_target_dim(d)
model.init(dataFeat)
model.apply_to_feature_matrix(dataFeat)
except Exception as e:
q.put(-1)
return -1
time = totalTimer.ElapsedTime()
q.put(time)
return time