Python Dataset.sa['dissimilarity']方法代码示例

# 需要导入模块: from mvpa2.datasets.base import Dataset [as 别名]
# 或者: from mvpa2.datasets.base.Dataset import sa['dissimilarity'] [as 别名]

#.........这里部分代码省略.........
    # fisher
    dissims = np.arctanh(dissims)

    # generate target clean "picture"
    d = np.asanyarray(dissims[0])
    signal_clean = np.zeros(shape + (len(vector_form(d)),))

    # generate ground truth for clustering
    cluster_truth = np.zeros(shape, dtype='int')

    if rois_arrangement == 'circle':
        radius = min(shape[:2])/4.
        center = np.array((radius*2,) * len(shape)).astype(int)
        # arrange at quarter distance from center
        for i, dissim in enumerate(dissims):
            dissim = vector_form(dissim)
            # that is kinda boring -- the same dissimilarity to each
            # voxel???
            #
            # TODO: come up with a better arrangement/idea, e.g. to
            # generate an MVPA pattern which would satisfy the
            # dissimilarity (not exactly but at least close).  That
            # would make more sense
            roi_center = center.copy()
            roi_center[0] += int(radius * np.cos(2*np.pi*i/ndissims))
            roi_center[1] += int(radius * np.sin(2*np.pi*i/ndissims))
            for coords in roi_neighborhood(roi_center):
                acoords = np.asanyarray(coords)
                if np.all(acoords >= [0]*len(coords)) and \
                   np.all(acoords < signal_clean.shape[:len(coords)]):
                    signal_clean.__setitem__(coords, dissim)
                    cluster_truth.__setitem__(coords, i+1)
    else:
        raise ValueError("I know only circle")

    # generated randomly and will be mixed into subjects with different weights
    # TODO: static across runs within subject??  if so -- would be no different
    #       from having RSAs?
    common_noises = get_intrinsic_noises(
        signal_clean.shape,
        std=noise_common_std,
        sigma=noise_common_smooth,
        n=noise_common_n)
    assert common_noises[0].ndim == 3, "There should be no time comp"

    # Now lets generate per subject and per run data by adding some noise(s)
    # all_signals = []
    dss = []
    for isubject in xrange(nsubjects):
        # Interesting noise, simulating some underlying process which has nothing
        # to do with original design/similarity but having spatial structure which
        # repeats through runs with random weights (consider it to be a principal component)

        # generated randomly for each subject separately, but they should have
        # common structure across runs
        subj_specific_noises = get_intrinsic_noises(signal_clean.shape,
                                                std=noise_subject_std,
                                                sigma=noise_subject_smooth,
                                                n=noise_subject_n)
        assert subj_specific_noises[0].ndim == 3, "There should be no time comp"
        # subject_signals = []
        dss_subject = []
        subj_common_noises = [noise * np.random.normal()
                              for noise in common_noises]

        subj_specific_mixins = generate_mixins(nruns)
        subj_common_mixins = generate_mixins(nruns)

        for run in range(nruns):
            signal_run = signal_clean.copy()
            for noise in subj_specific_noises:
                signal_run += noise * subj_specific_mixins[run]
            for noise in subj_common_noises:
                signal_run += noise * subj_common_mixins[run]
            # generic noise -- no common structure across subjects/runs
            signal_run += filter_each_2d(
                np.random.normal(size=signal_clean.shape)*noise_independent_std,
                noise_independent_smooth)

            # go back to correlations with inverse of fisher
            signal_run = np.tanh(signal_run)
            # rollaxis to bring similarities into leading dimension
            ds = Dataset(np.rollaxis(signal_run, 2, 0))
            ds.sa['chunks'] = [run]
            ds.sa['dissimilarity'] = np.arange(len(dissim))  # Lame one for now
            ds_flat = ds.get_mapped(FlattenMapper(shape=ds.shape[1:],
                                                  space='pixel_indices'))
            dss_subject.append(ds_flat)
            #subject_signals.append(signal_run)
        #all_signals.append(subject_signals)
        ds = dsvstack(dss_subject)
        ds.a['mapper'] = dss_subject[0].a.mapper   # .a are not transferred by vstack
        dss.append(ds)

    # Instrumental noise -- the most banal
    assert(len(dss) == nsubjects)
    assert(len(dss) == nsubjects)
    assert(len(dss[0]) == nruns*len(dissim))

    return np.tanh(signal_clean), cluster_truth, dss