def preprocessor_apply_to_train(preproc, X):
"""
Apply Preprocessor to training data and memorize parameters
preproc is initially a struct with the following fields [default]
standardize_X - if True, makes columns of X zero mean and unit var. [True]
rescale_X - if True, scale columns of X to lie in [-1, +1] [False]
kernel_fn - if not None, apply kernel fn to X default [None]
The returned preproc object has several more fields added to it,
which are used by preprocessor_apply_to_test
"""
# Set defaults
try:
preproc.standardize_X
except AttributeError:
preproc.standardize_X = True
try:
preproc.rescale_X
except AttributeError:
preproc.rescale_X = False
try:
preproc.kernel_fn
except AttributeError:
preproc.kernel_fn = None
try:
preproc.poly
except AttributeError:
preproc.poly = None
try:
preproc.add_ones
except AttributeError:
preproc.add_ones = None
if preproc.standardize_X:
X, preproc.Xmu = util.center_cols(X)
X, preproc.Xstnd = util.mk_unit_variance(X)
if preproc.rescale_X:
try:
preproc.Xscale
except AttributeError:
preproc.Xscale = [-1, 1]
X = util.rescale_data(X, preproc.Xscale[0], preproc.Xscale[1])
if preproc.kernel_fn is not None:
preproc.basis = X
X = preproc.kernel_fn(X, preproc.basis)
if preproc.poly is not None:
assert preproc.poly > 0, 'polynomial degree must be greater than 0'
X = util.degexpand(X, preproc.poly, False)
if preproc.add_ones:
X = util.add_ones(X)
return preproc, X
def preprocessor_apply_to_test(preproc, X):
"""Transform the test data in the same way as the training data"""
try:
X = util.center_cols(X, preproc.Xmu)
except AttributeError:
pass
try:
X = util.mk_unit_variance(X, preproc.Xstnd)
except AttributeError:
pass
try:
X = util.rescale_data(X, preproc.Xscale[0], preproc.Xscale[1])
except AttributeError:
pass
try:
if preproc.kernel_fn is not None:
X = preproc.kernel_fn(X, preproc.basis)
except AttributeError:
pass
try:
if preproc.poly is not None:
X = util.degexpand(X, preproc.poly, False)
except AttributeError:
pass
try:
if preproc.add_ones:
X = util.add_ones(X)
except AttributeError:
pass
return X
