Python base.dataset_wizard函数代码示例

    def test_correct_dimensions_order(self, clf):
        """To check if known/present Classifiers are working properly
        with samples being first dimension. Started to worry about
        possible problems while looking at sg where samples are 2nd
        dimension
        """
        # specially crafted dataset -- if dimensions are flipped over
        # the same storage, problem becomes unseparable. Like in this case
        # incorrect order of dimensions lead to equal samples [0, 1, 0]
        traindatas = [
            dataset_wizard(samples=np.array([ [0, 0, 1.0],
                                        [1, 0, 0] ]), targets=[0, 1]),
            dataset_wizard(samples=np.array([ [0, 0.0],
                                      [1, 1] ]), targets=[0, 1])]

        clf.ca.change_temporarily(enable_ca = ['training_stats'])
        for traindata in traindatas:
            clf.train(traindata)
            self.assertEqual(clf.ca.training_stats.percent_correct, 100.0,
                "Classifier %s must have 100%% correct learning on %s. Has %f" %
                (`clf`, traindata.samples, clf.ca.training_stats.percent_correct))

            # and we must be able to predict every original sample thus
            for i in xrange(traindata.nsamples):
                sample = traindata.samples[i,:]
                predicted = clf.predict([sample])
                self.assertEqual([predicted], traindata.targets[i],
                    "We must be able to predict sample %s using " % sample +
                    "classifier %s" % `clf`)
        clf.ca.reset_changed_temporarily()

    def test_feature_selection_classifier(self):
        from mvpa2.featsel.base import \
             SensitivityBasedFeatureSelection
        from mvpa2.featsel.helpers import \
             FixedNElementTailSelector

        # should give lowest weight to the feature with lowest index
        sens_ana = SillySensitivityAnalyzer()
        # should give lowest weight to the feature with highest index
        sens_ana_rev = SillySensitivityAnalyzer(mult=-1)

        # corresponding feature selections
        feat_sel = SensitivityBasedFeatureSelection(sens_ana,
            FixedNElementTailSelector(1, mode='discard'))

        feat_sel_rev = SensitivityBasedFeatureSelection(sens_ana_rev,
            FixedNElementTailSelector(1))

        samples = np.array([ [0, 0, -1], [1, 0, 1], [-1, -1, 1],
                            [-1, 0, 1], [1, -1, 1] ])

        testdata3 = dataset_wizard(samples=samples, targets=1)
        # dummy train data so proper mapper gets created
        traindata = dataset_wizard(samples=np.array([ [0, 0, -1], [1, 0, 1] ]),
                            targets=[1, 2])

        # targets
        res110 = [1, 1, 1, -1, -1]
        res011 = [-1, 1, -1, 1, -1]

        # first classifier -- 0th feature should be discarded
        clf011 = FeatureSelectionClassifier(self.clf_sign, feat_sel,
                    enable_ca=['feature_ids'])

        self.clf_sign.ca.change_temporarily(enable_ca=['estimates'])
        clf011.train(traindata)

        self.assertEqual(clf011.predict(testdata3.samples), res011)
        # just silly test if we get values assigned in the 'ProxyClassifier'
        self.assertTrue(len(clf011.ca.estimates) == len(res110),
                        msg="We need to pass values into ProxyClassifier")
        self.clf_sign.ca.reset_changed_temporarily()

        self.assertEqual(clf011.mapper._oshape, (2,))
        "Feature selection classifier had to be trained on 2 features"

        # first classifier -- last feature should be discarded
        clf011 = FeatureSelectionClassifier(self.clf_sign, feat_sel_rev)
        clf011.train(traindata)
        self.assertEqual(clf011.predict(testdata3.samples), res110)

    def test_coarsen_chunks(self):
        """Just basic testing for now"""
        chunks = [1,1,2,2,3,3,4,4]
        ds = dataset_wizard(samples=np.arange(len(chunks)).reshape(
            (len(chunks),1)), targets=[1]*8, chunks=chunks)
        coarsen_chunks(ds, nchunks=2)
        chunks1 = coarsen_chunks(chunks, nchunks=2)
        self.assertTrue((chunks1 == ds.chunks).all())
        self.assertTrue((chunks1 == np.asarray([0,0,0,0,1,1,1,1])).all())

        ds2 = dataset_wizard(samples=np.arange(len(chunks)).reshape(
            (len(chunks),1)), targets=[1]*8, chunks=range(len(chunks)))
        coarsen_chunks(ds2, nchunks=2)
        self.assertTrue((chunks1 == ds.chunks).all())

def dumb_feature_binary_dataset():
    """Very simple binary (2 labels) dataset
    """
    data = [
        [1, 0],
        [1, 1],
        [2, 0],
        [2, 1],
        [3, 0],
        [3, 1],
        [4, 0],
        [4, 1],
        [5, 0],
        [5, 1],
        [6, 0],
        [6, 1],
        [7, 0],
        [7, 1],
        [8, 0],
        [8, 1],
        [9, 0],
        [9, 1],
        [10, 0],
        [10, 1],
        [11, 0],
        [11, 1],
        [12, 0],
        [12, 1],
    ]
    regs = ([0] * 12) + ([1] * 12)

    return dataset_wizard(samples=np.array(data), targets=regs, chunks=range(len(regs)))

def dumb_feature_dataset():
    """Create a very simple dataset with 2 features and 3 labels
    """
    data = [
        [1, 0],
        [1, 1],
        [2, 0],
        [2, 1],
        [3, 0],
        [3, 1],
        [4, 0],
        [4, 1],
        [5, 0],
        [5, 1],
        [6, 0],
        [6, 1],
        [7, 0],
        [7, 1],
        [8, 0],
        [8, 1],
        [9, 0],
        [9, 1],
        [10, 0],
        [10, 1],
        [11, 0],
        [11, 1],
        [12, 0],
        [12, 1],
    ]
    regs = ([1] * 8) + ([2] * 8) + ([3] * 8)

    return dataset_wizard(samples=np.array(data), targets=regs, chunks=range(len(regs)))

def linear1d_gaussian_noise(size=100, slope=0.5, intercept=1.0, x_min=-2.0, x_max=3.0, sigma=0.2):
    """A straight line with some Gaussian noise.
    """
    x = np.linspace(start=x_min, stop=x_max, num=size)
    noise = np.random.randn(size) * sigma
    y = x * slope + intercept + noise
    return dataset_wizard(samples=x[:, None], targets=y)

def test_DissimilarityConsistencyMeasure():
    targets = np.tile(xrange(3),2)
    chunks = np.repeat(np.array((0,1)),3)
    # correct results
    cres1 = 0.41894348
    cres2 = np.array([[ 0.16137995, 0.73062639, 0.59441713]])
    dc1 = data[0:3,:] - np.mean(data[0:3,:],0)
    dc2 = data[3:6,:] - np.mean(data[3:6,:],0)
    center = squareform(np.corrcoef(pdist(dc1,'correlation'),pdist(dc2,'correlation')), 
                        checks=False).reshape((1,-1))
    dsm1 = stats.rankdata(pdist(data[0:3,:],'correlation').reshape((1,-1)))
    dsm2 = stats.rankdata(pdist(data[3:6,:],'correlation').reshape((1,-1)))

    spearman = squareform(np.corrcoef(np.vstack((dsm1,dsm2))), 
                        checks=False).reshape((1,-1))
    
    ds = dataset_wizard(samples=data, targets=targets, chunks=chunks)
    dscm = DissimilarityConsistencyMeasure()
    res1 = dscm(ds)
    dscm_c = DissimilarityConsistencyMeasure(center_data=True)
    res2 = dscm_c(ds)
    dscm_sp = DissimilarityConsistencyMeasure(consistency_metric='spearman')
    res3 = dscm_sp(ds)
    ds.append(ds)
    chunks = np.repeat(np.array((0,1,2,)),4)
    ds.sa['chunks'] = chunks
    res4 = dscm(ds)
    assert_almost_equal(np.mean(res1.samples),cres1)
    assert_array_almost_equal(res2.samples, center)
    assert_array_almost_equal(res3.samples, spearman)
    assert_array_almost_equal(res4.samples,cres2)

def test_PDist():
    targets = np.tile(xrange(3),2)
    chunks = np.repeat(np.array((0,1)),3)
    ds = dataset_wizard(samples=data, targets=targets, chunks=chunks)
    data_c = data - np.mean(data,0)
    # DSM matrix elements should come out as samples of one feature
    # to be in line with what e.g. a classifier returns -- facilitates
    # collection in a searchlight ...
    euc = pdist(data, 'euclidean')[None].T
    pear = pdist(data, 'correlation')[None].T
    city = pdist(data, 'cityblock')[None].T
    center_sq = squareform(pdist(data_c,'correlation'))

    # Now center each chunk separately
    dsm1 = PDist()
    dsm2 = PDist(pairwise_metric='euclidean')
    dsm3 = PDist(pairwise_metric='cityblock')
    dsm4 = PDist(center_data=True,square=True)
    assert_array_almost_equal(dsm1(ds).samples,pear)
    assert_array_almost_equal(dsm2(ds).samples,euc)
    dsm_res = dsm3(ds)
    assert_array_almost_equal(dsm_res.samples,city)
    # length correspondings to a single triangular matrix
    assert_equal(len(dsm_res.sa.pairs), len(ds) * (len(ds) - 1) / 2)
    # generate label pairs actually reflect the vectorform generated by
    # squareform()
    dsm_res_square = squareform(dsm_res.samples.T[0])
    for i, p in enumerate(dsm_res.sa.pairs):
        assert_equal(dsm_res_square[p[0], p[1]], dsm_res.samples[i, 0])
    dsm_res = dsm4(ds)
    assert_array_almost_equal(dsm_res.samples,center_sq)
    # sample attributes are carried over
    assert_almost_equal(ds.sa.targets, dsm_res.sa.targets)

def _test_mcasey20120222():  # pragma: no cover
    # http://lists.alioth.debian.org/pipermail/pkg-exppsy-pymvpa/2012q1/002034.html

    # This one is conditioned on allowing # of samples to be changed
    # by the mapper provided to MappedClassifier.  See
    # https://github.com/yarikoptic/PyMVPA/tree/_tent/allow_ch_nsamples

    import numpy as np
    from mvpa2.datasets.base import dataset_wizard
    from mvpa2.generators.partition import NFoldPartitioner
    from mvpa2.mappers.base import ChainMapper
    from mvpa2.mappers.svd import SVDMapper
    from mvpa2.mappers.fx import mean_group_sample
    from mvpa2.clfs.svm import LinearCSVMC
    from mvpa2.clfs.meta import MappedClassifier
    from mvpa2.measures.base import CrossValidation

    mapper = ChainMapper([mean_group_sample(['targets','chunks']),
                          SVDMapper()])
    clf = MappedClassifier(LinearCSVMC(), mapper)
    cvte = CrossValidation(clf, NFoldPartitioner(),
                           enable_ca=['repetition_results', 'stats'])

    ds = dataset_wizard(
        samples=np.arange(32).reshape((8, -1)),
        targets=[1, 1, 2, 2, 1, 1, 2, 2],
        chunks=[1, 1, 1, 1, 2, 2, 2, 2])

    errors = cvte(ds)

    def test_feature_selection_classifier_with_regression(self):
        from mvpa2.featsel.base import \
             SensitivityBasedFeatureSelection
        from mvpa2.featsel.helpers import \
             FixedNElementTailSelector
        if sample_clf_reg is None:
            # none regression was found, so nothing to test
            return
        # should give lowest weight to the feature with lowest index
        sens_ana = SillySensitivityAnalyzer()

        # corresponding feature selections
        feat_sel = SensitivityBasedFeatureSelection(sens_ana,
            FixedNElementTailSelector(1, mode='discard'))

        # now test with regression-based classifier. The problem is
        # that it is determining predictions twice from values and
        # then setting the values from the results, which the second
        # time is set to predictions.  The final outcome is that the
        # values are actually predictions...
        dat = dataset_wizard(samples=np.random.randn(4, 10),
                      targets=[-1, -1, 1, 1])
        clf_reg = FeatureSelectionClassifier(sample_clf_reg, feat_sel)
        clf_reg.train(dat)
        _ = clf_reg.predict(dat.samples)
        self.failIf((np.array(clf_reg.ca.estimates)
                     - clf_reg.ca.predictions).sum()==0,
                    msg="Values were set to the predictions in %s." %
                    sample_clf_reg)

def test_mapper_vs_zscore():
    """Test by comparing to results of elderly z-score function
    """
    # data: 40 sample feature line in 20d space (40x20; samples x features)
    dss = [
        dataset_wizard(np.concatenate(
            [np.arange(40) for i in range(20)]).reshape(20,-1).T,
                targets=1, chunks=1),
        ] + datasets.values()

    for ds in dss:
        ds1 = deepcopy(ds)
        ds2 = deepcopy(ds)

        zsm = ZScoreMapper(chunks_attr=None)
        assert_raises(RuntimeError, zsm.forward, ds1.samples)
        idhashes = (idhash(ds1), idhash(ds1.samples))
        zsm.train(ds1)
        idhashes_train = (idhash(ds1), idhash(ds1.samples))
        assert_equal(idhashes, idhashes_train)

        # forward dataset
        ds1z_ds = zsm.forward(ds1)
        idhashes_forwardds = (idhash(ds1), idhash(ds1.samples))
        # must not modify samples in place!
        assert_equal(idhashes, idhashes_forwardds)

        # forward samples explicitly
        ds1z = zsm.forward(ds1.samples)
        idhashes_forward = (idhash(ds1), idhash(ds1.samples))
        assert_equal(idhashes, idhashes_forward)

        zscore(ds2, chunks_attr=None)
        assert_array_almost_equal(ds1z, ds2.samples)
        assert_array_equal(ds1.samples, ds.samples)

def test_origid_handling():
    ds = dataset_wizard(np.atleast_2d(np.arange(35)).T)
    ds.init_origids('both')
    ok_(ds.nsamples == 35)
    assert_equal(len(np.unique(ds.sa.origids)), 35)
    assert_equal(len(np.unique(ds.fa.origids)), 1)
    selector = [3, 7, 10, 15]
    subds = ds[selector]
    assert_array_equal(subds.sa.origids, ds.sa.origids[selector])

    # Now if we request new origids if they are present we could
    # expect different behavior
    assert_raises(ValueError, subds.init_origids, 'both', mode='raises')
    sa_origids = subds.sa.origids.copy()
    fa_origids = subds.fa.origids.copy()
    for s in ('both', 'samples', 'features'):
        assert_raises(RuntimeError, subds.init_origids, s, mode='raise')
        subds.init_origids(s, mode='existing')
        # we should have the same origids as before
        assert_array_equal(subds.sa.origids, sa_origids)
        assert_array_equal(subds.fa.origids, fa_origids)

    # Lets now change, which should be default behavior
    subds.init_origids('both')
    assert_equal(len(sa_origids), len(subds.sa.origids))
    assert_equal(len(fa_origids), len(subds.fa.origids))
    # values should change though
    ok_((sa_origids != subds.sa.origids).any())
    ok_((fa_origids != subds.fa.origids).any())

def test_idhash():
    ds = dataset_wizard(np.arange(12).reshape((4, 3)),
                 targets=1, chunks=1)
    origid = ds.idhash
    #XXX BUG -- no assurance that labels would become an array... for now -- do manually
    ds.targets = np.array([3, 1, 2, 3])   # change all labels
    ok_(origid != ds.idhash,
                    msg="Changing all targets should alter dataset's idhash")

    origid = ds.idhash

    z = ds.targets[1]
    assert_equal(origid, ds.idhash,
                 msg="Accessing shouldn't change idhash")
    z = ds.chunks
    assert_equal(origid, ds.idhash,
                 msg="Accessing shouldn't change idhash")
    z[2] = 333
    ok_(origid != ds.idhash,
        msg="Changing value in attribute should change idhash")

    origid = ds.idhash
    ds.samples[1, 1] = 1000
    ok_(origid != ds.idhash,
        msg="Changing value in data should change idhash")

    origid = ds.idhash
    orig_labels = ds.targets #.copy()
    ds.sa.targets = range(len(ds))
    ok_(origid != ds.idhash,
        msg="Chaging attribute also changes idhash")

    ds.targets = orig_labels
    ok_(origid == ds.idhash,
        msg="idhash should be restored after reassigning orig targets")

def pure_multivariate_signal(patterns, signal2noise = 1.5, chunks=None, targets=[0, 1]):
    """ Create a 2d dataset with a clear multivariate signal, but no
    univariate information.

    ::

      %%%%%%%%%
      % O % X %
      %%%%%%%%%
      % X % O %
      %%%%%%%%%
    """

    # start with noise
    data = np.random.normal(size=(4*patterns, 2))

    # add signal
    data[:2*patterns, 1] += signal2noise

    data[2*patterns:4*patterns, 1] -= signal2noise
    data[:patterns, 0] -= signal2noise
    data[2*patterns:3*patterns, 0] -= signal2noise
    data[patterns:2*patterns, 0] += signal2noise
    data[3*patterns:4*patterns, 0] += signal2noise

    # two conditions
    regs = np.array((targets[0:1] * patterns) + (targets[1:2] * 2 * patterns) + (targets[0:1] * patterns))

    if chunks is None:
        chunks = range(len(data))
    return dataset_wizard(samples=data, targets=regs, chunks=chunks)

    def test_aggregation(self):
        data = dataset_wizard(np.arange( 20 ).reshape((4, 5)), targets=1, chunks=1)

        ag_data = aggregate_features(data, np.mean)

        ok_(ag_data.nsamples == 4)
        ok_(ag_data.nfeatures == 1)
        assert_array_equal(ag_data.samples[:, 0], [2, 7, 12, 17])