def __potential_boundaries__(segmentation_a, segmentation_b, **kwargs):
boundary_format = kwargs['boundary_format']
boundary_string_a = segmentation_a
boundary_string_b = segmentation_b
# Convert from NLTK types
if boundary_format == BoundaryFormat.nltk:
boundary_string_a = convert_nltk_to_masses(segmentation_a)
boundary_string_b = convert_nltk_to_masses(segmentation_b)
boundary_format = BoundaryFormat.mass
# Check format
if boundary_format == BoundaryFormat.sets:
pass
elif boundary_format == BoundaryFormat.mass:
boundary_string_a = boundary_string_from_masses(boundary_string_a)
boundary_string_b = boundary_string_from_masses(boundary_string_b)
elif boundary_format == BoundaryFormat.position:
boundary_string_a = convert_positions_to_masses(boundary_string_a)
boundary_string_b = convert_positions_to_masses(boundary_string_b)
boundary_string_a = boundary_string_from_masses(boundary_string_a)
boundary_string_b = boundary_string_from_masses(boundary_string_b)
else:
raise SegmentationMetricError('Unsupported boundary format')
# Compute boundary types if required
boundary_types = identify_types(boundary_string_a, boundary_string_b)
return len(boundary_string_a) * len(boundary_types)
def __boundary_statistics__(
segs_a, segs_b, boundary_types, boundary_format, n_t, weight):
'''
Compute boundary similarity applying the weighting functions specified.
'''
# Convert from NLTK types
if boundary_format == BoundaryFormat.nltk:
segs_a = convert_nltk_to_masses(segs_a)
segs_b = convert_nltk_to_masses(segs_b)
boundary_format = BoundaryFormat.mass
# Check format
if boundary_format == BoundaryFormat.sets:
pass # Correct boundary format
elif boundary_format == BoundaryFormat.mass:
segs_a = boundary_string_from_masses(segs_a)
segs_b = boundary_string_from_masses(segs_b)
elif boundary_format == BoundaryFormat.position:
segs_a = convert_positions_to_masses(segs_a)
segs_b = convert_positions_to_masses(segs_b)
segs_a = boundary_string_from_masses(segs_a)
segs_b = boundary_string_from_masses(segs_b)
else:
raise SegmentationMetricError('Unsupported boundary format')
# Check length
if len(segs_a) != len(segs_b):
raise SegmentationMetricError(
'Segmentations differ in length ({0} != {1})'.format(
len(segs_a), len(segs_b)))
# Determine the boundary types
boundary_types = identify_types(segs_a, segs_b)
# Calculate the total pbs
pbs = len(segs_b) * len(boundary_types)
# Compute edits
additions, substitutions, transpositions = \
boundary_edit_distance(segs_a, segs_b, n_t=n_t)
# Apply weighting functions
fnc_weight_a, fnc_weight_s, fnc_weight_t = weight
count_additions = fnc_weight_a(additions)
count_substitutions = fnc_weight_s(substitutions,
max(boundary_types),
min(boundary_types))
count_transpositions = fnc_weight_t(transpositions, n_t)
count_edits = count_additions + count_substitutions + count_transpositions
# Compute
matches = list()
full_misses = list()
boundaries_all = 0
for set_a, set_b in zip(segs_a, segs_b):
matches.extend(set_a.intersection(set_b))
full_misses.extend(set_a.symmetric_difference(set_b))
boundaries_all += len(set_a) + len(set_b)
return {'count_edits': count_edits, 'additions': additions,
'substitutions': substitutions, 'transpositions': transpositions,
'full_misses': full_misses, 'boundaries_all': boundaries_all,
'matches': matches, 'pbs': pbs, 'boundary_types': boundary_types}
def __pk__(hypothesis, reference, window_size, one_minus, boundary_format,
return_parts, fnc_round):
# Convert from NLTK types
if boundary_format == BoundaryFormat.nltk:
reference = convert_nltk_to_masses(reference)
hypothesis = convert_nltk_to_masses(hypothesis)
boundary_format = BoundaryFormat.mass
# Convert from masses into positions
if boundary_format == BoundaryFormat.mass:
reference = convert_masses_to_positions(reference)
hypothesis = convert_masses_to_positions(hypothesis)
elif boundary_format != BoundaryFormat.position:
raise SegmentationMetricError('Unsupported boundary format')
# Check for input errors
if len(reference) != len(hypothesis):
raise SegmentationMetricError(
'Reference and hypothesis segmentations differ in position length ({0} is not {1}).'
.format(len(reference), len(hypothesis)))
# Compute window size to use if unspecified
if window_size is None:
window_size = __compute_window_size__(reference, fnc_round,
BoundaryFormat.position)
# Create a set of pairs of units from each segmentation to go over using a
# window
sum_differences = 0
# Slide window over and sum the number of varying windows
measurements = 0
for i in range(0, len(reference) - (window_size)):
# Create probe windows with k boundaries inside
window_ref = reference[i:i + window_size + 1]
window_hyp = hypothesis[i:i + window_size + 1]
# Probe agreement
agree_ref = window_ref[0] is window_ref[-1]
agree_hyp = window_hyp[0] is window_hyp[-1]
# If the windows agreements agree
if agree_ref is not agree_hyp:
sum_differences += 1
measurements += 1
# Perform final division
value = Decimal(sum_differences) / measurements if measurements > 0 else 0
if return_parts:
return sum_differences, measurements
else:
if one_minus:
return Decimal('1.0') - value
else:
return value
def __pk__(hypothesis, reference, window_size, one_minus, boundary_format,
return_parts, fnc_round):
# Convert from NLTK types
if boundary_format == BoundaryFormat.nltk:
reference = convert_nltk_to_masses(reference)
hypothesis = convert_nltk_to_masses(hypothesis)
boundary_format = BoundaryFormat.mass
# Convert from masses into positions
if boundary_format == BoundaryFormat.mass:
reference = convert_masses_to_positions(reference)
hypothesis = convert_masses_to_positions(hypothesis)
elif boundary_format != BoundaryFormat.position:
raise SegmentationMetricError('Unsupported boundary format')
# Check for input errors
if len(reference) != len(hypothesis):
raise SegmentationMetricError(
'Reference and hypothesis segmentations differ in position length ({0} is not {1}).'.format(len(reference), len(hypothesis)))
# Compute window size to use if unspecified
if window_size is None:
window_size = __compute_window_size__(reference, fnc_round,
BoundaryFormat.position)
# Create a set of pairs of units from each segmentation to go over using a
# window
sum_differences = 0
# Slide window over and sum the number of varying windows
measurements = 0
for i in range(0, len(reference) - (window_size)):
# Create probe windows with k boundaries inside
window_ref = reference[i:i + window_size + 1]
window_hyp = hypothesis[i:i + window_size + 1]
# Probe agreement
agree_ref = window_ref[0] is window_ref[-1]
agree_hyp = window_hyp[0] is window_hyp[-1]
# If the windows agreements agree
if agree_ref is not agree_hyp:
sum_differences += 1
measurements += 1
# Perform final division
value = Decimal(sum_differences) / measurements if measurements > 0 else 0
if return_parts:
return sum_differences, measurements
else:
if one_minus:
return Decimal('1.0') - value
else:
return value
def __boundaries__(segmentation, **kwargs):
boundary_format = kwargs['boundary_format']
boundary_string = segmentation
# Convert from NLTK types
if boundary_format == BoundaryFormat.nltk:
boundary_string = convert_nltk_to_masses(segmentation)
boundary_format = BoundaryFormat.mass
# Check format
if boundary_format == BoundaryFormat.sets:
pass
elif boundary_format == BoundaryFormat.mass:
boundary_string = boundary_string_from_masses(boundary_string)
elif boundary_format == BoundaryFormat.position:
boundary_string = convert_positions_to_masses(boundary_string)
boundary_string = boundary_string_from_masses(boundary_string)
else:
raise SegmentationMetricError('Unsupported boundary format')
return sum([len(position) for position in boundary_string])
def __boundary_statistics__(segs_a, segs_b, boundary_types, boundary_format,
n_t, weight):
'''
Compute boundary similarity applying the weighting functions specified.
'''
# Convert from NLTK types
if boundary_format == BoundaryFormat.nltk:
segs_a = convert_nltk_to_masses(segs_a)
segs_b = convert_nltk_to_masses(segs_b)
boundary_format = BoundaryFormat.mass
# Check format
if boundary_format == BoundaryFormat.sets:
pass # Correct boundary format
elif boundary_format == BoundaryFormat.mass:
segs_a = boundary_string_from_masses(segs_a)
segs_b = boundary_string_from_masses(segs_b)
elif boundary_format == BoundaryFormat.position:
segs_a = convert_positions_to_masses(segs_a)
segs_b = convert_positions_to_masses(segs_b)
segs_a = boundary_string_from_masses(segs_a)
segs_b = boundary_string_from_masses(segs_b)
else:
raise SegmentationMetricError('Unsupported boundary format')
# Check length
if len(segs_a) != len(segs_b):
raise SegmentationMetricError(
'Segmentations differ in length ({0} != {1})'.format(
len(segs_a), len(segs_b)))
# Determine the boundary types
boundary_types = identify_types(segs_a, segs_b)
# Calculate the total pbs
pbs = len(segs_b) * len(boundary_types)
# Compute edits
additions, substitutions, transpositions = \
boundary_edit_distance(segs_a, segs_b, n_t=n_t)
# Apply weighting functions
fnc_weight_a, fnc_weight_s, fnc_weight_t = weight
count_additions = fnc_weight_a(additions)
count_substitutions = fnc_weight_s(substitutions, max(boundary_types),
min(boundary_types))
count_transpositions = fnc_weight_t(transpositions, n_t)
count_edits = count_additions + count_substitutions + count_transpositions
# Compute
matches = list()
full_misses = list()
boundaries_all = 0
for set_a, set_b in zip(segs_a, segs_b):
matches.extend(set_a.intersection(set_b))
full_misses.extend(set_a.symmetric_difference(set_b))
boundaries_all += len(set_a) + len(set_b)
return {
'count_edits': count_edits,
'additions': additions,
'substitutions': substitutions,
'transpositions': transpositions,
'full_misses': full_misses,
'boundaries_all': boundaries_all,
'matches': matches,
'pbs': pbs,
'boundary_types': boundary_types
}
def test_convert_nltk_to_masses_pk_long(self):
'''
NLTK-style segmentations starting with a boundary.
'''
self.assertEqual(convert_nltk_to_masses('0100100000'), (2, 3, 6))
self.assertEqual(convert_nltk_to_masses('0101000000'), (2, 2, 7))
def test_convert_nltk_to_masses_pk_ab(self):
'''
NLTK-style segmentations starting with a boundary.
'''
self.assertEqual(convert_nltk_to_masses('100'), (1,3))
self.assertEqual(convert_nltk_to_masses('010'), (2,2))
def __window_diff__(hypothesis, reference, window_size, one_minus,
boundary_format, return_parts, fnc_round,
lamprier_et_al_2007_fix):
'''
Calculates the WindowDiff segmentation evaluation metric score for a
hypothetical segmentation against a reference segmentation for a given
window size. The standard method of calculating the window size
is performed a window size is not specified.
:param hypothesis: Hypothesis segmentation section labels
sequence.
:param reference: Reference segmentation section labels
sequence.
:param window_size: The size of the window that is slid over \
the two segmentations used to count \
mismatches (default is None and will \
use the average window size)
:param one_minus: Return 1-WindowDiff to make it no longer \
a penalty-metric.
:param lamprier_et_al_2007_fix: Apply a fix for improperly counted errors \
at the beginning and end of \
segmentations, provided by \
_[LamprierEtAl2007].
:param convert_from_masses: Convert the segmentations provided from \
masses into positions.
:type hypothesis: list
:type reference: list
:type window_size: int
:type one_minus: bool
:type lamprier_et_al_2007_fix: bool
:type convert_from_masses: bool
.. note:: See :func:`segeval.convert_masses_to_positions` for an example of
the input format.
'''
# Convert from NLTK types
if boundary_format == BoundaryFormat.nltk:
reference = convert_nltk_to_masses(reference)
hypothesis = convert_nltk_to_masses(hypothesis)
boundary_format = BoundaryFormat.mass
# Convert from masses into positions
if boundary_format == BoundaryFormat.mass:
reference = convert_masses_to_positions(reference)
hypothesis = convert_masses_to_positions(hypothesis)
elif boundary_format != BoundaryFormat.position:
raise SegmentationMetricError('Unsupported boundary format')
# Check for input errors
if len(reference) != len(hypothesis):
raise SegmentationMetricError(
'Reference and hypothesis segmentations differ in position \
length (%(ref)i is not %(hyp)i).' % {
'ref': len(reference),
'hyp': len(hypothesis)
})
# Compute window size to use if unspecified
if window_size is None:
window_size = __compute_window_size__(reference, fnc_round,
BoundaryFormat.position)
# Create a set of pairs of units from each segmentation to go over using a
# window
units_ref_hyp = __create_paired_window__(hypothesis, reference,
window_size,
lamprier_et_al_2007_fix)[0]
# Slide window over and sum the number of varying windows
sum_differences = 0
measurements = len(units_ref_hyp) - window_size
for i in range(0, measurements):
window = units_ref_hyp[i:i + window_size + 1]
ref_boundaries = 0
hyp_boundaries = 0
# Check that the number of loops is correct
assert len(window) == window_size + 1
# For pair in window
for j in range(0, len(window) - 1):
ref_part, hyp_part = zip(*window[j:j + 2])
# Boundary exists in the reference segmentation
if ref_part[0] is not ref_part[1]:
ref_boundaries += 1
# Boundary exists in the hypothesis segmentation
if hyp_part[0] is not hyp_part[1]:
hyp_boundaries += 1
# If the number of boundaries per segmentation in the window differs
if ref_boundaries is not hyp_boundaries:
sum_differences += 1
# Perform final division
n = sum(convert_positions_to_masses(reference))
denominator = n - window_size
if lamprier_et_al_2007_fix:
denominator = measurements + 1
win_diff = Decimal(sum_differences) / denominator
# Check normalization
assert denominator == measurements or lamprier_et_al_2007_fix
# Check value
assert win_diff <= 1
if not one_minus:
if return_parts:
return sum_differences, denominator
else:
return win_diff
else:
return Decimal('1.0') - win_diff
def __window_diff__(hypothesis, reference, window_size, one_minus,
boundary_format, return_parts, fnc_round,
lamprier_et_al_2007_fix):
'''
Calculates the WindowDiff segmentation evaluation metric score for a
hypothetical segmentation against a reference segmentation for a given
window size. The standard method of calculating the window size
is performed a window size is not specified.
:param hypothesis: Hypothesis segmentation section labels
sequence.
:param reference: Reference segmentation section labels
sequence.
:param window_size: The size of the window that is slid over \
the two segmentations used to count \
mismatches (default is None and will \
use the average window size)
:param one_minus: Return 1-WindowDiff to make it no longer \
a penalty-metric.
:param lamprier_et_al_2007_fix: Apply a fix for improperly counted errors \
at the beginning and end of \
segmentations, provided by \
_[LamprierEtAl2007].
:param convert_from_masses: Convert the segmentations provided from \
masses into positions.
:type hypothesis: list
:type reference: list
:type window_size: int
:type one_minus: bool
:type lamprier_et_al_2007_fix: bool
:type convert_from_masses: bool
.. note:: See :func:`segeval.convert_masses_to_positions` for an example of
the input format.
'''
# Convert from NLTK types
if boundary_format == BoundaryFormat.nltk:
reference = convert_nltk_to_masses(reference)
hypothesis = convert_nltk_to_masses(hypothesis)
boundary_format = BoundaryFormat.mass
# Convert from masses into positions
if boundary_format == BoundaryFormat.mass:
reference = convert_masses_to_positions(reference)
hypothesis = convert_masses_to_positions(hypothesis)
elif boundary_format != BoundaryFormat.position:
raise SegmentationMetricError('Unsupported boundary format')
# Check for input errors
if len(reference) != len(hypothesis):
raise SegmentationMetricError(
'Reference and hypothesis segmentations differ in position \
length (%(ref)i is not %(hyp)i).' % {'ref': len(reference),
'hyp': len(hypothesis)})
# Compute window size to use if unspecified
if window_size is None:
window_size = __compute_window_size__(reference, fnc_round,
BoundaryFormat.position)
# Create a set of pairs of units from each segmentation to go over using a
# window
units_ref_hyp = __create_paired_window__(hypothesis, reference,
window_size,
lamprier_et_al_2007_fix)[0]
# Slide window over and sum the number of varying windows
sum_differences = 0
measurements = len(units_ref_hyp) - window_size
for i in range(0, measurements):
window = units_ref_hyp[i: i + window_size + 1]
ref_boundaries = 0
hyp_boundaries = 0
# Check that the number of loops is correct
assert len(window) is window_size + 1
# For pair in window
for j in range(0, len(window) - 1):
ref_part, hyp_part = zip(*window[j:j + 2])
# Boundary exists in the reference segmentation
if ref_part[0] is not ref_part[1]:
ref_boundaries += 1
# Boundary exists in the hypothesis segmentation
if hyp_part[0] is not hyp_part[1]:
hyp_boundaries += 1
# If the number of boundaries per segmentation in the window differs
if ref_boundaries is not hyp_boundaries:
sum_differences += 1
# Perform final division
n = sum(convert_positions_to_masses(reference))
denominator = n - window_size
if lamprier_et_al_2007_fix:
denominator = measurements + 1
win_diff = Decimal(sum_differences) / denominator
# Check normalization
assert denominator == measurements or lamprier_et_al_2007_fix
# Check value
assert win_diff <= 1
if not one_minus:
if return_parts:
return sum_differences, denominator
else:
return win_diff
else:
return Decimal('1.0') - win_diff