def test_004_med_mad(self):
x = np.array([[0.5, 0.5, 0.5, 0.5], [0.5, 0.5, 1.0, 1.0],
[0.0, 0.5, 0.5, 1.0]])
factor = 1
loc, scale = maths.med_mad(x, factor=factor)
self.assertTrue(np.allclose(loc, 0.5))
self.assertTrue(np.allclose(scale, 0))
def sample_filter_parameters(read_data,
number_to_sample,
chunk_len,
filter_mean_dwell,
filter_max_dwell,
chunk_len_means_sequence_len=False):
"""Sample number_to_sample reads from read_data, calculate median and MAD
of mean dwell. Note the MAD has an adjustment factor so that it would give the
same result as the std for a normal distribution.
See docstring for sample_chunks() for the parameters.
"""
no_filter_params = FILTER_PARAMETERS(filter_mean_dwell=filter_mean_dwell,
filter_max_dwell=filter_max_dwell,
median_meandwell=None,
mad_meandwell=None)
chunks, _ = sample_chunks(
read_data,
number_to_sample,
chunk_len,
no_filter_params,
chunk_len_means_sequence_len=chunk_len_means_sequence_len)
meandwells = [get_mean_dwell(chunk) for chunk in chunks]
median_meandwell, mad_meandwell = med_mad(meandwells)
return FILTER_PARAMETERS(filter_mean_dwell=filter_mean_dwell,
filter_max_dwell=filter_max_dwell,
median_meandwell=median_meandwell,
mad_meandwell=mad_meandwell)
def sample_filter_parameters(read_data, number_to_sample, chunk_len,
filter_mean_dwell, filter_max_dwell,
filter_min_pass_fraction,
model_stride, path_buffer,
chunk_len_means_sequence_len=False):
""" Sample number_to_sample reads from read_data, calculate median and MAD
of mean dwell. Note the MAD has an adjustment factor so that it would give
the same result as the std for a normal distribution.
See FILTER_PARAMETERS docstring for details.
"""
no_filter_params = FILTER_PARAMETERS(
filter_mean_dwell=filter_mean_dwell, filter_max_dwell=filter_max_dwell,
filter_min_pass_fraction=filter_min_pass_fraction,
median_meandwell=None, mad_meandwell=None,
model_stride=None, path_buffer=None)
chunks, _ = sample_chunks(
read_data, number_to_sample, chunk_len, no_filter_params,
chunk_len_means_sequence_len=chunk_len_means_sequence_len)
meandwells = [chunk.mean_dwell for chunk in chunks]
median_meandwell, mad_meandwell = med_mad(meandwells)
return FILTER_PARAMETERS(
filter_mean_dwell=filter_mean_dwell, filter_max_dwell=filter_max_dwell,
filter_min_pass_fraction=filter_min_pass_fraction,
median_meandwell=median_meandwell, mad_meandwell=mad_meandwell,
model_stride=model_stride, path_buffer=path_buffer)
def one_read_shift_scale(read_tuple):
read_filename, read_id = read_tuple
try:
with fast5_interface.get_fast5_file(read_filename, 'r') as f5file:
read = f5file.get_read(read_id)
sig = Signal(read)
except Exception as e:
sys.stderr.write(
'Unable to obtain signal for {} from {}.\n{}\n'.format(
read_id, read_filename, repr(e)))
return (None, None, None)
else:
signal = sig.current
if len(signal) > 0:
shift, scale = med_mad(signal)
else:
shift, scale = np.NaN, np.NaN
# note - if signal trimmed by ub, it could be of length zero by this point for short reads
# These are taken out later in the existing code, in the new code we'll take out ub trimming
return (read_id, shift, scale)
def test_004_med_mad(self):
"""Test to see if med_mad works with axis not set (so flattening)."""
x = np.array([[0.5, 0.5, 0.5, 0.5], [0.5, 0.5, 1.0, 1.0],
[0.0, 0.5, 0.5, 1.0]])
factor = 1
loc, scale = maths.med_mad(x, factor=factor)
self.assertTrue(np.allclose(loc, 0.5))
self.assertTrue(np.allclose(scale, 0))
def test_006_med_mad_over_axis1(self):
x = np.array([[0.5, 0.5, 0.5, 0.5], [0.5, 0.5, 1.0, 1.0],
[0.0, 0.5, 0.5, 1.0]])
factor = 1
loc, scale = maths.med_mad(x, factor=factor, axis=1)
expected_loc = [0.5, 0.75, 0.5]
expected_scale = [0, 0.25, 0.25]
self.assertTrue(np.allclose(loc, expected_loc))
self.assertTrue(np.allclose(scale, expected_scale))
def test_005_med_mad_over_axis0(self):
"""Test to see if med_mad works when axis=0."""
x = np.array([[0.5, 0.5, 0.5, 0.5], [0.5, 0.5, 1.0, 1.0],
[0.5, 1.0, 0.5, 1.0]])
factor = 1
loc, scale = maths.med_mad(x, factor=factor, axis=0)
expected_loc = [0.5, 0.5, 0.5, 1.0]
expected_scale = [0, 0, 0, 0]
self.assertTrue(np.allclose(loc, expected_loc))
self.assertTrue(np.allclose(scale, expected_scale))
def sample_filter_parameters(read_data, number_to_sample, chunk_len, args,
log=None, chunk_log=None,
chunk_len_means_sequence_len = False):
"""Sample number_to_sample reads from read_data, calculate median and MAD
of mean dwell. Note the MAD has an adjustment factor so that it would give the
same result as the std for a normal distribution.
See docstring for sample_chunks() for the parameters.
"""
meandwells, _ = sample_chunks(read_data, number_to_sample, chunk_len, args, get_mean_dwell,
log=log, chunk_log=chunk_log, log_accepted_chunks=True,
chunk_len_means_sequence_len=chunk_len_means_sequence_len)
return med_mad(meandwells)
def med_mad_norm(x, dtype='f4'):
""" Normalise a numpy array using median and MAD
Args:
x (:class:`ndarray`): 1D array containing values to be normalised.
dtype (str or :class:`dtype`): dtype of returned array.
Returns:
:class:`ndarray`: Array of same shape as `x` and dtype `dtype`
contained normalised values.
"""
med, mad = med_mad(x)
normed_x = (x - med) / mad
return normed_x.astype(dtype)
def one_read_shift_scale(read_tuple):
""" Read signal from fast5 and perform medmad scaling
Args:
read_tuple (tuple of str and str): A filename and the read_id to read
from it.
Returns:
tuple of str and float and float: read_id of the read and the
calculated shift and scale parameters.
If the signal is unable to be read from the file, the read_id is not
present for example, then (None, , None, None) is returned.
When a signal is read, but has zero length, the shift and scale
returned are `np.NaN`
"""
read_filename, read_id = read_tuple
try:
with fast5_interface.get_fast5_file(read_filename, 'r') as f5file:
read = f5file.get_read(read_id)
sig = Signal(read)
except Exception as e:
sys.stderr.write(
'Unable to obtain signal for {} from {}.\n{}\n'.format(
read_id, read_filename, repr(e)))
return (None, None, None)
else:
signal = sig.current
if len(signal) > 0:
shift, scale = med_mad(signal)
else:
shift, scale = np.NaN, np.NaN
# Note - if signal trimmed by ub, it could be of length zero by
# this point for short reads
# These are taken out later in the existing code, in the new code
# we'll take out ub trimming
return (read_id, shift, scale)
def med_mad_norm(x, dtype='f4'):
""" Normalise a numpy array using median and MAD """
med, mad = med_mad(x)
normed_x = (x - med) / mad
return normed_x.astype(dtype)
def main():
args = get_parser().parse_args()
out_fp = sys.stdout if args.output is None else open(args.output, 'w')
sys.stderr.write('* Reading data from file\n')
out_fp.write('*' * 10 + ' General Metrics ' + '*' * 10 + '\n')
with MappedSignalReader(args.input) as msr:
alphabet_info = msr.get_alphabet_information()
out_fp.write('Alphabet: {}\n'.format(str(alphabet_info)))
read_ids = msr.get_read_ids()
out_fp.write('Total reads: {}\n'.format(len(read_ids)))
if args.num_reads is not None:
np.random.shuffle(read_ids)
read_ids = read_ids[:args.num_reads]
reads = list(msr.reads(read_ids))
sys.stderr.write('* Computing sanity check metrics\n')
out_fp.write('\n\n' + '*' * 10 + ' Sanity Checks ' + '*' * 10 + '\n')
current_meds = np.array([np.median(read.get_current()) for read in reads])
out_fp.write((
'Median of medians of normalized signal: {:.6f} (should usually ' +
'be close to 0)\n').format(np.median(current_meds)))
current_mads = np.array([
np.median(np.abs(read.get_current() - r_med)) * MAD_SD_FACTOR
for read, r_med in zip(reads, current_meds)])
out_fp.write((
'Median of standardized MADs of normalized signal: {:.6f} ' +
'(should usually be close to 1.0)\n').format(np.median(current_mads)))
all_seqs = np.concatenate([read.Reference for read in reads])
seq_counts = np.bincount(all_seqs)
total_bases = np.sum(seq_counts)
out_fp.write(
'Global sequence composition:\n{: >11}{: >11}{: >11}\n'.format(
'base', 'count', 'percent') + '\n'.join(
'{: >11}{:11.0f}{:11.4f}'.format(*base_metrics)
for base_metrics in zip(
alphabet_info.alphabet, seq_counts,
100 * seq_counts / total_bases)) + '\n')
if args.motif is not None:
sys.stderr.write('* Computing motif metrics (this may take a ' +
'while to complete)\n')
out_fp.write('\n\n' + '*' * 10 + ' Motif Metrics ' + '*' * 10 + '\n')
def match_motif(seq, motif):
for base, motif_pos_bases in zip(seq, motif):
if base not in motif_pos_bases:
return False
return True
motifs = [
([np.concatenate([np.where([m_base == a_base for a_base in
alphabet_info.collapse_alphabet])[0]
for m_base in SINGLE_LETTER_CODE[m_raw_base]])
for m_raw_base in motif], int(rel_pos))
for motif, rel_pos in args.motif]
motif_mod_counts = [[] for _ in range(len(motifs))]
for read in reads:
for motif_i, (motif, rel_pos) in enumerate(motifs):
for offset in range(read.Reference.shape[0] - len(motif)):
if match_motif(
read.Reference[offset:offset + len(motif)], motif):
motif_mod_counts[motif_i].append(
read.Reference[offset + rel_pos])
for (raw_motif, rel_pos), m_mod_counts in zip(
args.motif, motif_mod_counts):
rel_pos = int(rel_pos)
motif_mod_counts = np.bincount(m_mod_counts)
total_mod_bases = np.sum(motif_mod_counts)
out_fp.write(
('{} Motif Modified Base Counts:\n{: >11}{: >11}' +
'{: >11}\n').format(raw_motif, 'base', 'count', 'percent') +
'\n'.join('{: >11}{:11.0f}{:11.4f}'.format(
raw_motif[:rel_pos] + base + raw_motif[rel_pos + 1:],
count, pct) for base, count, pct in zip(
alphabet_info.alphabet, motif_mod_counts,
100 * motif_mod_counts / total_mod_bases)
if count > 0) + '\n\n')
sys.stderr.write('* Computing read metrics\n')
out_fp.write('\n' + '*' * 10 + ' Read Metrics ' + '*' * 10 + '\n')
read_lens = np.array([read.reflen for read in reads])
out_fp.write(('Median read length: {}\n').format(np.median(read_lens)))
sig_lens = np.array([read.siglen for read in reads])
out_fp.write(('Median signal length: {}\n').format(
np.median(sig_lens)))
if args.num_chunks is None:
return
sys.stderr.write('* Computing chunk metrics\n')
out_fp.write('\n\n' + '*' * 10 + ' Chunk Metrics ' + '*' * 10 + '\n')
chunks, rej_res = [], []
while len(chunks) < args.num_chunks:
chunk = np.random.choice(reads, 1)[0].get_chunk_with_sample_length(
args.chunk_len)
if chunk.accepted:
chunks.append(chunk)
else:
rej_res.append(chunk.reject_reason)
if len(rej_res) > 0:
out_fp.write(
'Chunk rejection reasons:\n{: >16}{: >16}\n'.format(
'Reject Reason', 'Num. Chunks') +
'\n'.join('{: >16}{: >16}'.format(*x)
for x in Counter(rej_res).most_common()) + '\n\n')
else:
out_fp.write('All chunks passed filters\n\n')
mean_dwells = np.array([chunk.mean_dwell for chunk in chunks])
max_dwells = np.array([chunk.max_dwell for chunk in chunks])
# report in MAD units for direct use in command line parameter usage
median_meandwell, mad_meandwell = med_mad(mean_dwells)
out_fp.write(
('Chunk dwell distribution (standard units for direct use with ' +
'--filter_max_dwell and --filter_mean_dwell):\n' +
'{: >15}{: >15}{: >15}{: >15}{: >15}\n').format(
'percentile', 'mean_dwell', 'mean_std_units',
'max_dwell', 'max_std_units') +
'\n'.join('{:15.2f}{:15.2f}{:15.2f}{:15.2f}{:15.2f}'.format(
*pctl_metrics) for pctl_metrics in zip(
args.chunk_percentiles,
np.percentile(mean_dwells, args.chunk_percentiles),
np.percentile(mean_dwells - median_meandwell / mad_meandwell,
args.chunk_percentiles),
np.percentile(max_dwells, args.chunk_percentiles),
np.percentile(max_dwells / median_meandwell,
args.chunk_percentiles))) + '\n')
if args.output is not None:
out_fp.close()