def monte_carlo_group_distances_within_between(single_field, \
paired_field, dmat, dir_prefix = '', \
subdir_prefix='monte_carlo_group_distances',\
num_iters=10):
"""Calculate Monte Carlo stats within and between fields.
Specifically:
- find the groups for each specified col (or combination of cols)
- do t test between each pair of groups
- randomize matrix n times and find empirical value of t for each pair
- compare the actual value of t to the randomized values
WARNING: Only symmetric, hollow distance matrices may be used as input.
Asymmetric distance matrices, such as those obtained by the UniFrac Gain
metric (i.e. beta_diversity.py -m unifrac_g), should not be used as input.
"""
path_prefix = path.join(dir_prefix, subdir_prefix)
#if dir doesn't exist
if not path.isdir(path_prefix):
# make directory
mkdir(path_prefix)
real_dists = []
within_category_distances = \
within_category_distances_grouped(single_field,label_suffix='')
real_dists.extend([['Within',field,distances] for field,\
distances in within_category_distances.items()])
between_category_distances = \
between_category_distances_grouped(single_field,label_suffix='')
real_dists.extend([['Between',field,distances] for field,\
distances in between_category_distances.items()])
within_and_between = \
within_and_between_fields(paired_field)
real_dists.extend([[field.split('_',1)[0],\
field.split('_',1)[1],distances] for \
field, distances in within_and_between.items()])
outfile = open(
path.join(path_prefix, 'group_distances_within_and_between.txt'), 'w')
outfile.write('\t'.join(['Comparison','Category_1','Avg',\
'Comparison','Category_2','Avg','t','p',\
'p_greater','p_less','Iterations\n']))
rand_distances = get_random_dists(real_dists, dmat, num_iters)
#iterate over the groups
for i, (first_g1, second_g1, distances_g1) in \
enumerate(real_dists[:-1]):
real_dist_1 = average(distances_g1)
rand_dists_1 = [rand_distances[n][i][-1] for n in range(num_iters)]
#then for each other pair (not including same group)
for j in range(i + 1, len(real_dists)):
first_g2, second_g2, distances_g2 = real_dists[j]
real_dist_2 = average(distances_g2)
rand_dists_2 = [rand_distances[n][j][-1] \
for n in range(num_iters)]
ttests = [t_two_sample(rand_dists_1[n],rand_dists_2[n])[0] \
for n in range(num_iters)]
real_ttest = t_two_sample(distances_g1, distances_g2)
curr_line = [first_g1, second_g1, real_dist_1, \
first_g2, second_g2, real_dist_2]
curr_line.extend([real_ttest[0], real_ttest[1],\
(array(ttests)>real_ttest[0]).sum()/float(num_iters), \
(array(ttests)<real_ttest[0]).sum()/float(num_iters), \
num_iters])
outfile.write('\t'.join(map(str, curr_line)))
outfile.write('\n')
def compare_alpha_diversities(rarefaction_lines,
mapping_lines,
category,
depth=None,
test_type='nonparametric',
num_permutations=999):
"""Compares alpha diversity values for differences per category treatment.
Notes:
Returns a defaultdict which as keys has the pairs of treatments being
compared, and as values, lists of (pval,tval) tuples for each comparison at
for a given iteration.
Inputs:
rarefaction_lines - list of lines, result of multiple rarefactions.
mapping_lines - list of lines, mapping file lines.
category - str, the category to be compared, eg 'Treatment' or 'Age'.
depth - int, depth of the rarefaction file to use. if None, then will use
the deepest available in the file.
test_type - str, the type of t-test to perform. Must be either
'parametric' or 'nonparametric'.
num_permutations - int, the number of Monte Carlo permutations to use if
test_type is 'nonparametric'.
"""
if test_type == 'nonparametric' and num_permutations < 1:
raise ValueError("Invalid number of permutations: %d. Must be greater "
"than zero." % num_permutations)
rarefaction_data = parse_rarefaction(rarefaction_lines)
mapping_data = parse_mapping_file_to_dict(mapping_lines)[0]
# samid_pairs, treatment_pairs are in the same order
samid_pairs, treatment_pairs = sampleId_pairs(mapping_data,
rarefaction_data, category)
# extract only rows of the rarefaction data that are at the given depth
# if depth is not given default to the deepest rarefaction available
# rarefaction file is not guaranteed to be in order of rarefaction depth
if depth == None:
depth = array(rarefaction_data[3])[:, 0].max()
rare_mat = array([row for row in rarefaction_data[3] if row[0] == depth])
# Average each col of the rarefaction mtx. Computing t test on averages over
# all iterations. Avoids more comps which kills signifigance.
rare_mat = (rare_mat.sum(0) /
rare_mat.shape[0])[2:] #remove depth,iter cols
sids = rarefaction_data[0][3:] # 0-2 are header strings
ttest_results = {}
for sid_pair, treatment_pair in zip(samid_pairs, treatment_pairs):
# if there is only 1 sample for each treatment in a comparison, and mc
# using mc method, will error (e.g. mc_t_two_sample([1],[1]).
if len(sid_pair[0]) == 1 and len(sid_pair[1]) == 1:
ttest_results[treatment_pair] = (None, None)
else:
pair0_indices = [sids.index(i) for i in sid_pair[0]]
pair1_indices = [sids.index(i) for i in sid_pair[1]]
i = rare_mat.take(pair0_indices)
j = rare_mat.take(pair1_indices)
# found discussion of how to quickly check an array for nan here:
# http://stackoverflow.com/questions/6736590/fast-check-for-nan-in-numpy
if isnan(np_min(i)) or isnan(np_min(j)):
ttest_results[treatment_pair] = (None, None)
continue
if test_type == 'parametric':
obs_t, p_val = t_two_sample(i, j)
elif test_type == 'nonparametric':
obs_t, _, _, p_val = mc_t_two_sample(
i, j, permutations=num_permutations)
if p_val != None:
p_val = float(
format_p_value_for_num_iters(
p_val, num_iters=num_permutations))
elif p_val == None: #None will error in format_p_val
obs_t, p_val = None, None
else:
raise ValueError("Invalid test type '%s'." % test_type)
ttest_results[treatment_pair] = (obs_t, p_val)
# create dict of average alpha diversity values
alphadiv_avgs = {}
for sid_pair, treatment_pair in zip(samid_pairs, treatment_pairs):
# calculate the alpha diversity average, std vals. choosing only first
# treatment pair doesn't guarantees full covering, must look at both
for sid_list, treatment_str in zip(sid_pair, treatment_pair):
# check if already computed and added
if not treatment_str in alphadiv_avgs.keys():
alphadiv_vals = \
rare_mat.take([sids.index(i) for i in sid_list])
ad_mean = alphadiv_vals.mean()
ad_std = alphadiv_vals.std()
alphadiv_avgs[treatment_str] = (ad_mean, ad_std)
return ttest_results, alphadiv_avgs
def monte_carlo_group_distances(mapping_file, dmatrix_file, prefs, \
dir_prefix = '', subdir_prefix='monte_carlo_group_distances',\
default_iters=10, fields=None):
"""Calculate Monte Carlo stats for specified group distances.
Specifically:
- find the groups for each specified col (or combination of cols)
- do t test between each pair of groups
- randomize matrix n times and find empirical value of t for each pair
- compare the actual value of t to the randomized values
WARNING: Only symmetric, hollow distance matrices may be used as input.
Asymmetric distance matrices, such as those obtained by the UniFrac Gain
metric (i.e. beta_diversity.py -m unifrac_g), should not be used as input.
"""
mapping, header, comments = parse_mapping_file(open(mapping_file, 'U'))
header = [header]
header.extend(mapping)
mapping = header
distance_header, distance_matrix = \
parse_distmat(open(dmatrix_file,'U'))
orig_distance_matrix = distance_matrix.copy()
path_prefix = path.join(dir_prefix, subdir_prefix)
#if dir doesn't exist
if not path.isdir(path_prefix):
# make directory
mkdir(path_prefix)
if fields is None:
fields = [mapping[0][0]]
if prefs is None:
prefs = {}
if 'MONTE_CARLO_GROUP_DISTANCES' not in prefs:
prefs = build_monte_carlo_prefs(fields, default_iters)
for field, num_iters in prefs['MONTE_CARLO_GROUP_DISTANCES'].items():
if '&&' in field:
groups = group_by_fields(mapping, field.split('&&'))
else:
groups = group_by_field(mapping, field)
outfile = open(
path.join(path_prefix, 'group_distances_' + field + '.txt'), 'w')
outfile.write('\t'.join(['Category_1a','Category_1b','Avg',\
'Category_2a','Category_2b','Avg','t','p',\
'p_greater','p_less','Iterations\n']))
real_dists = distances_by_groups(distance_header, distance_matrix,\
groups)
#iterate over the groups
for i, (first_g1, second_g1, distances_g1) in \
enumerate(real_dists[:-1]):
real_dist_1 = average(distances_g1)
#then for each other pair (not including same group)
for j in range(i + 1, len(real_dists)):
first_g2, second_g2, distances_g2 = real_dists[j]
real_dist_2 = average(distances_g2)
# permute distances just within these groups!
rand_dists_1, rand_dists_2 = \
permute_between_groups(distances_g1,
distances_g2,
num_iters)
ttests = [t_two_sample(rand_dists_1[n].flatten(),rand_dists_2[n].flatten())[0] \
for n in range(num_iters)]
real_ttest = t_two_sample(distances_g1.flatten(),
distances_g2.flatten())
curr_line = [first_g1, second_g1, real_dist_1, \
first_g2, second_g2, real_dist_2]
curr_line.extend([real_ttest[0], real_ttest[1],\
(array(ttests)>real_ttest[0]).sum()/float(num_iters), \
(array(ttests)<real_ttest[0]).sum()/float(num_iters), \
num_iters])
outfile.write('\t'.join(map(str, curr_line)))
outfile.write('\n')
def monte_carlo_group_distances_within_between(single_field, \
paired_field, dmat, dir_prefix = '', \
subdir_prefix='monte_carlo_group_distances',\
num_iters=10):
"""Calculate Monte Carlo stats within and between fields.
Specifically:
- find the groups for each specified col (or combination of cols)
- do t test between each pair of groups
- randomize matrix n times and find empirical value of t for each pair
- compare the actual value of t to the randomized values
WARNING: Only symmetric, hollow distance matrices may be used as input.
Asymmetric distance matrices, such as those obtained by the UniFrac Gain
metric (i.e. beta_diversity.py -m unifrac_g), should not be used as input.
"""
path_prefix = path.join(dir_prefix,subdir_prefix)
#if dir doesn't exist
if not path.isdir(path_prefix):
# make directory
mkdir(path_prefix)
real_dists = []
within_category_distances = \
within_category_distances_grouped(single_field,label_suffix='')
real_dists.extend([['Within',field,distances] for field,\
distances in within_category_distances.items()])
between_category_distances = \
between_category_distances_grouped(single_field,label_suffix='')
real_dists.extend([['Between',field,distances] for field,\
distances in between_category_distances.items()])
within_and_between = \
within_and_between_fields(paired_field)
real_dists.extend([[field.split('_',1)[0],\
field.split('_',1)[1],distances] for \
field, distances in within_and_between.items()])
outfile = open(path.join(path_prefix,
'group_distances_within_and_between.txt'), 'w')
outfile.write('\t'.join(['Comparison','Category_1','Avg',\
'Comparison','Category_2','Avg','t','p',\
'p_greater','p_less','Iterations\n']))
rand_distances = get_random_dists(real_dists, dmat, num_iters)
#iterate over the groups
for i, (first_g1, second_g1, distances_g1) in \
enumerate(real_dists[:-1]):
real_dist_1 = average(distances_g1)
rand_dists_1 = [rand_distances[n][i][-1] for n in range(num_iters)]
#then for each other pair (not including same group)
for j in range(i+1,len(real_dists)):
first_g2, second_g2, distances_g2 = real_dists[j]
real_dist_2 = average(distances_g2)
rand_dists_2 = [rand_distances[n][j][-1] \
for n in range(num_iters)]
ttests = [t_two_sample(rand_dists_1[n],rand_dists_2[n])[0] \
for n in range(num_iters)]
real_ttest = t_two_sample(distances_g1, distances_g2)
curr_line = [first_g1, second_g1, real_dist_1, \
first_g2, second_g2, real_dist_2]
curr_line.extend([real_ttest[0], real_ttest[1],\
(array(ttests)>real_ttest[0]).sum()/float(num_iters), \
(array(ttests)<real_ttest[0]).sum()/float(num_iters), \
num_iters])
outfile.write('\t'.join(map(str, curr_line)))
outfile.write('\n')
def monte_carlo_group_distances(mapping_file, dmatrix_file, prefs, \
dir_prefix = '', subdir_prefix='monte_carlo_group_distances',\
default_iters=10, fields=None):
"""Calculate Monte Carlo stats for specified group distances.
Specifically:
- find the groups for each specified col (or combination of cols)
- do t test between each pair of groups
- randomize matrix n times and find empirical value of t for each pair
- compare the actual value of t to the randomized values
WARNING: Only symmetric, hollow distance matrices may be used as input.
Asymmetric distance matrices, such as those obtained by the UniFrac Gain
metric (i.e. beta_diversity.py -m unifrac_g), should not be used as input.
"""
mapping, header, comments = parse_mapping_file(open(mapping_file,'U'))
header = [header]
header.extend(mapping)
mapping=header
distance_header, distance_matrix = \
parse_distmat(open(dmatrix_file,'U'))
orig_distance_matrix = distance_matrix.copy()
path_prefix = path.join(dir_prefix,subdir_prefix)
#if dir doesn't exist
if not path.isdir(path_prefix):
# make directory
mkdir(path_prefix)
if fields is None:
fields = [mapping[0][0]]
if prefs is None:
prefs = {}
if 'MONTE_CARLO_GROUP_DISTANCES' not in prefs:
prefs = build_monte_carlo_prefs(fields,default_iters)
for field, num_iters in prefs['MONTE_CARLO_GROUP_DISTANCES'].items():
if '&&' in field:
groups = group_by_fields(mapping, field.split('&&'))
else:
groups = group_by_field(mapping, field)
outfile = open(path.join(path_prefix,
'group_distances_'+field+'.txt'), 'w')
outfile.write('\t'.join(['Category_1a','Category_1b','Avg',\
'Category_2a','Category_2b','Avg','t','p',\
'p_greater','p_less','Iterations\n']))
real_dists = distances_by_groups(distance_header, distance_matrix,\
groups)
#iterate over the groups
for i, (first_g1, second_g1, distances_g1) in \
enumerate(real_dists[:-1]):
real_dist_1 = average(distances_g1)
#then for each other pair (not including same group)
for j in range(i+1,len(real_dists)):
first_g2, second_g2, distances_g2 = real_dists[j]
real_dist_2 = average(distances_g2)
# permute distances just within these groups!
rand_dists_1, rand_dists_2 = \
permute_between_groups(distances_g1,
distances_g2,
num_iters)
ttests = [t_two_sample(rand_dists_1[n].flatten(),rand_dists_2[n].flatten())[0] \
for n in range(num_iters)]
real_ttest = t_two_sample(distances_g1.flatten(), distances_g2.flatten())
curr_line = [first_g1, second_g1, real_dist_1, \
first_g2, second_g2, real_dist_2]
curr_line.extend([real_ttest[0], real_ttest[1],\
(array(ttests)>real_ttest[0]).sum()/float(num_iters), \
(array(ttests)<real_ttest[0]).sum()/float(num_iters), \
num_iters])
outfile.write('\t'.join(map(str, curr_line)))
outfile.write('\n')
def compare_alpha_diversities(rarefaction_lines, mapping_lines, category,
depth=None, test_type='nonparametric', num_permutations=999):
"""Compares alpha diversity values for differences per category treatment.
Notes:
Returns a defaultdict which as keys has the pairs of treatments being
compared, and as values, lists of (pval,tval) tuples for each comparison at
for a given iteration.
Inputs:
rarefaction_lines - list of lines, result of multiple rarefactions.
mapping_lines - list of lines, mapping file lines.
category - str, the category to be compared, eg 'Treatment' or 'Age'.
depth - int, depth of the rarefaction file to use. if None, then will use
the deepest available in the file.
test_type - str, the type of t-test to perform. Must be either
'parametric' or 'nonparametric'.
num_permutations - int, the number of Monte Carlo permutations to use if
test_type is 'nonparametric'.
"""
if test_type == 'nonparametric' and num_permutations < 1:
raise ValueError("Invalid number of permutations: %d. Must be greater "
"than zero." % num_permutations)
rarefaction_data = parse_rarefaction(rarefaction_lines)
mapping_data = parse_mapping_file_to_dict(mapping_lines)[0]
# samid_pairs, treatment_pairs are in the same order
samid_pairs, treatment_pairs = sampleId_pairs(mapping_data,
rarefaction_data, category)
# extract only rows of the rarefaction data that are at the given depth
# if depth is not given default to the deepest rarefaction available
# rarefaction file is not guaranteed to be in order of rarefaction depth
if depth == None:
depth = array(rarefaction_data[3])[:,0].max()
rare_mat = array([row for row in rarefaction_data[3] if row[0]==depth])
# Average each col of the rarefaction mtx. Computing t test on averages over
# all iterations. Avoids more comps which kills signifigance.
rare_mat = (rare_mat.sum(0)/rare_mat.shape[0])[2:] #remove depth,iter cols
sids = rarefaction_data[0][3:] # 0-2 are header strings
ttest_results = {}
for sid_pair, treatment_pair in zip(samid_pairs, treatment_pairs):
# if there is only 1 sample for each treatment in a comparison, and mc
# using mc method, will error (e.g. mc_t_two_sample([1],[1]).
if len(sid_pair[0])==1 and len(sid_pair[1])==1:
ttest_results[treatment_pair]= (None,None)
else:
pair0_indices = [sids.index(i) for i in sid_pair[0]]
pair1_indices = [sids.index(i) for i in sid_pair[1]]
i = rare_mat.take(pair0_indices)
j = rare_mat.take(pair1_indices)
# found discussion of how to quickly check an array for nan here:
# http://stackoverflow.com/questions/6736590/fast-check-for-nan-in-numpy
if isnan(np_min(i)) or isnan(np_min(j)):
ttest_results[treatment_pair]= (None,None)
continue
if test_type == 'parametric':
obs_t, p_val = t_two_sample(i,j)
elif test_type == 'nonparametric':
obs_t, _, _, p_val = mc_t_two_sample(i,j,
permutations=num_permutations)
if p_val != None:
p_val = float(format_p_value_for_num_iters(p_val,
num_iters=num_permutations))
elif p_val == None: #None will error in format_p_val
obs_t, p_val = None, None
else:
raise ValueError("Invalid test type '%s'." % test_type)
ttest_results[treatment_pair]= (obs_t,p_val)
# create dict of average alpha diversity values
alphadiv_avgs = {}
for sid_pair, treatment_pair in zip(samid_pairs, treatment_pairs):
# calculate the alpha diversity average, std vals. choosing only first
# treatment pair doesn't guarantees full covering, must look at both
for sid_list, treatment_str in zip(sid_pair, treatment_pair):
# check if already computed and added
if not treatment_str in alphadiv_avgs.keys():
alphadiv_vals = \
rare_mat.take([sids.index(i) for i in sid_list])
ad_mean = alphadiv_vals.mean()
ad_std = alphadiv_vals.std()
alphadiv_avgs[treatment_str] = (ad_mean, ad_std)
return ttest_results, alphadiv_avgs
def compare_alpha_diversities(rarefaction_lines,
mapping_lines,
category,
depth=None,
test_type='nonparametric',
num_permutations=999):
"""Compares alpha diversity values for differences per category treatment.
Notes:
Returns a defaultdict which as keys has the pairs of treatments being
compared, and as values, lists of (pval,tval) tuples for each comparison at
for a given iteration.
Inputs:
rarefaction_lines - list of lines, result of multiple rarefactions.
mapping_lines - list of lines, mapping file lines.
category - str, the category to be compared, eg 'Treatment' or 'Age'.
depth - int, depth of the rarefaction file to use. if None, then will use
the deepest available in the file.
test_type - str, the type of t-test to perform. Must be either
'parametric' or 'nonparametric'.
num_permutations - int, the number of Monte Carlo permutations to use if
test_type is 'nonparametric'.
"""
if test_type == 'nonparametric' and num_permutations < 1:
raise ValueError("Invalid number of permutations: %d. Must be greater "
"than zero." % num_permutations)
rarefaction_data = parse_rarefaction(rarefaction_lines)
mapping_data = parse_mapping_file_to_dict(mapping_lines)[0]
# samid_pairs, treatment_pairs are in the same order
samid_pairs, treatment_pairs = sampleId_pairs(mapping_data,
rarefaction_data, category)
ps_avg_div = get_per_sample_average_diversities(rarefaction_data, depth)
ttest_results, ad_avgs = {}, {}
for sid_pair, treatment_pair in zip(samid_pairs, treatment_pairs):
# if there is only 1 sample for each treatment in a comparison, and mc
# using mc method, will error (e.g. mc_t_two_sample([1],[1]).
if len(sid_pair[0]) == 1 and len(sid_pair[1]) == 1:
ttest_results[treatment_pair] = (None, None)
# add alpha diversity averages and standard deviations. since their
# is only a single sample if we are in this part of the loop, we can
# just record the sample value as the avg and 0 as the std.
ad_avgs[treatment_pair[0]] = (sid_pair[0][0], 0.)
ad_avgs[treatment_pair[1]] = (sid_pair[1][0], 0.)
else:
i = array([ps_avg_div[x] for x in sid_pair[0]])
j = array([ps_avg_div[x] for x in sid_pair[1]])
# add alpha diversity averages and standard deviations.
ad_avgs[treatment_pair[0]] = (i.mean(), i.std())
ad_avgs[treatment_pair[1]] = (j.mean(), j.std())
# conduct tests
if isnan(np_min(i)) or isnan(np_min(j)):
ttest_results[treatment_pair] = (None, None)
continue
if test_type == 'parametric':
obs_t, p_val = t_two_sample(i, j)
elif test_type == 'nonparametric':
obs_t, _, _, p_val = mc_t_two_sample(
i, j, permutations=num_permutations)
if p_val != None:
p_val = float(
format_p_value_for_num_iters(
p_val, num_iters=num_permutations))
elif p_val == None: #None will error in format_p_val
obs_t, p_val = None, None
else:
raise ValueError("Invalid test type '%s'." % test_type)
ttest_results[treatment_pair] = (obs_t, p_val)
return ttest_results, ad_avgs
def compare_alpha_diversities(rarefaction_lines, mapping_lines, category,
depth=None, test_type='nonparametric', num_permutations=999):
"""Compares alpha diversity values for differences per category treatment.
Notes:
Returns a defaultdict which as keys has the pairs of treatments being
compared, and as values, lists of (pval,tval) tuples for each comparison at
for a given iteration.
Inputs:
rarefaction_lines - list of lines, result of multiple rarefactions.
mapping_lines - list of lines, mapping file lines.
category - str, the category to be compared, eg 'Treatment' or 'Age'.
depth - int, depth of the rarefaction file to use. if None, then will use
the deepest available in the file.
test_type - str, the type of t-test to perform. Must be either
'parametric' or 'nonparametric'.
num_permutations - int, the number of Monte Carlo permutations to use if
test_type is 'nonparametric'.
"""
if test_type == 'nonparametric' and num_permutations < 1:
raise ValueError("Invalid number of permutations: %d. Must be greater "
"than zero." % num_permutations)
rarefaction_data = parse_rarefaction(rarefaction_lines)
mapping_data = parse_mapping_file_to_dict(mapping_lines)[0]
# samid_pairs, treatment_pairs are in the same order
samid_pairs, treatment_pairs = sampleId_pairs(mapping_data,
rarefaction_data, category)
ps_avg_div = get_per_sample_average_diversities(rarefaction_data, depth)
ttest_results, ad_avgs = {}, {}
for sid_pair, treatment_pair in zip(samid_pairs, treatment_pairs):
# if there is only 1 sample for each treatment in a comparison, and mc
# using mc method, will error (e.g. mc_t_two_sample([1],[1]).
if len(sid_pair[0])==1 and len(sid_pair[1])==1:
ttest_results[treatment_pair]= (None,None)
# add alpha diversity averages and standard deviations. since their
# is only a single sample if we are in this part of the loop, we can
# just record the sample value as the avg and 0 as the std.
ad_avgs[treatment_pair[0]] = (sid_pair[0][0], 0.)
ad_avgs[treatment_pair[1]] = (sid_pair[1][0], 0.)
else:
i = array([ps_avg_div[x] for x in sid_pair[0]])
j = array([ps_avg_div[x] for x in sid_pair[1]])
# add alpha diversity averages and standard deviations.
ad_avgs[treatment_pair[0]] = (i.mean(), i.std())
ad_avgs[treatment_pair[1]] = (j.mean(), j.std())
# conduct tests
if isnan(np_min(i)) or isnan(np_min(j)):
ttest_results[treatment_pair]= (None,None)
continue
if test_type == 'parametric':
obs_t, p_val = t_two_sample(i,j)
elif test_type == 'nonparametric':
obs_t, _, _, p_val = mc_t_two_sample(i,j,
permutations=num_permutations)
if p_val != None:
p_val = float(format_p_value_for_num_iters(p_val,
num_iters=num_permutations))
elif p_val == None: #None will error in format_p_val
obs_t, p_val = None, None
else:
raise ValueError("Invalid test type '%s'." % test_type)
ttest_results[treatment_pair]= (obs_t,p_val)
return ttest_results, ad_avgs
