def blast_seqs (in_file, scratch_dir, result_dir, e_threshold=None,
max_hits=None):
log.info ('Blasting reads ...')
#
# read in seqfile
blast_cnt = 0
rdr = ExSeqReader (in_file, fmt=SCRATCH_FORMAT, merge_quals=False)
# for each sequence
for seq in rdr.read():
log.info ("Blasting sequence '%s' ..." % seq.id)
# blast it and write down to scratch
res = blast_ncbi (seq.format('fasta'),
e_threshold=e_threshold,
max_hits=max_hits,
)
blast_cnt += 1
scratch_hndl = fileutils.write_to_file ([result_dir, '%s.xml' % seq.id],
res.read())
# reduce and write to results
res.seek(0)
result_hndl = fileutils.write_to_file ([result_dir, '%s.xml' % seq.id],
res.read())
# summarize
## Postconditions & return:
log.info ('%s sequences were blasted ...' % blast_cnt)
def merge_and_trim_seqs (input_files, scratch_dir, input_format=None,
merge_quals=True, trim_right=None):
"""
Combine input sequence files, with merging with quality data and trimming.
These reads and merges all the inputs into a single file in the designated
intermediate format, combining them with any quality data available and
trimming the 3' end if required. It is possible that this stage may be
unnecessary (if the data is in a single file in the right format already and
no trimming is required) but this will almost never be the case.
"""
# TOOD: check for rare conditions where we don't need to do this
## Main:
if trim_right:
log.info ('Merging & trimming sequences ...')
else:
log.info ('Merging sequences ...')
# create & open file for filtered seqs
merged_out_hndl = create_intermediate_file ('merged_and_trimmed', scratch_dir)
# read in seqfiles
seq_cnt = 0
for f in input_files:
log.info ("Reading '%s' ..." % f)
# check file exists
assert (path.exists (f)), "the sequence file '%s' does not exist" % f
# set default format
if (input_format in [None, 'auto']):
fmt = None
else:
fmt = input_format
# make reader & read
rdr = ExSeqReader (f, fmt=fmt, merge_quals=merge_quals)
for seq in rdr.read():
log.debug ("Reading sequence '%s' ..." % seq.id)
# trim the sequnece if requested
if trim_right:
seq.seq = seq.seq[:-trim_right]
# write it out
SeqIO.write ([seq], merged_out_hndl, SCRATCH_FORMAT)
seq_cnt += 1
merged_out_hndl.close()
## Postconditions & return:
log.info ('%s sequences merged ...' % seq_cnt)
return merged_out_hndl.name
def cluster_seqs (infile, scratch_dir, cluster_fn):
# NOTE: the logic of this is quite hairy. We wish to traverse the number of
# times through the collection looking for similar seqs. At the same time,
# we don't wish to load the entirity of sequences into memory. So we open the
# infile file and read it one by one. For each sequence read, we read the file
# again and compare it to every sequence after it. The comparison (clustering)
# function returns None if the two sequences do not cluster. Otherwise it
# returns the preferred / better sequence of the two, which is then used for
# subsequent comparisons on this loop. We save on unnecessary comparsions by
# storing any sucessful matches in a "don't check" dict. We use a single file
# handle to searh one, rewinding as need be, to avoid opening and closing
# thousands.
## Main:
log.info ('Clustering sequences ...')
# create & open file for results, & open handl for searching / comparing
clustered_out_hndl = create_intermediate_file ('clustered', scratch_dir)
search_hndl = open (infile, 'r')
# read in seqfile and check seqs one-by-one
seq_cnt = 0
already_tested = {}
log.info ("Reading '%s' ..." % infile)
rdr = ExSeqReader (infile, fmt=SCRATCH_FORMAT, merge_quals=False)
for i, seq_1 in enumerate (rdr.read()):
log.debug ("Reading sequence '%s' ..." % seq_1.id)
# if this seq hasn't previously been clustered
if seq_1.id not in already_tested:
# move to start of search file & start reading
search_hndl.seek (0)
rdr_2 = ExSeqReader (search_hndl, fmt=SCRATCH_FORMAT, merge_quals=False)
# for every seq beyond the current one
for seq_2 in islice (rdr_2.read(), i+1, None):
# if it hasn't previously been clustered
if seq_2.id not in already_tested:
cluster_seq = cluster_fn (seq_1, seq_2)
# if it clusters, place in "done" dict and update search term
if cluster_seq:
already_tested[seq_2.id] = True
seq_1 = cluster_seq
# save the surviving search term
SeqIO.write ([seq_1], clustered_out_hndl, SCRATCH_FORMAT)
seq_cnt += 1
clustered_out_hndl.close()
search_hndl.close()
## Postconditions & return:
log.debug ('%s sequences remain after clustering ...' % seq_cnt)
return clustered_out_hndl.name
def filter_seqs (infile, scratch_dir, filters):
## Main:
log.info ('Filtering sequences ...')
# create & open file for filtered seqs
filtered_out_hndl = create_intermediate_file ('filtered', scratch_dir)
# read in seqfile
filter_cnt = 0
log.info ("Reading '%s' ..." % infile)
# make reader & read
rdr = ExSeqReader (infile, fmt=SCRATCH_FORMAT, merge_quals=False)
for seq in rdr.read():
log.debug ("Reading sequence '%s' ..." % seq.id)
# if it passes all filters
if all (filters):
log.debug ("Accepting '%s' ..." % seq.id)
SeqIO.write ([seq], filtered_out_hndl, SCRATCH_FORMAT)
filter_cnt += 1
else:
log.debug ("Rejecting '%s' ..." % seq.id)
filtered_out_hndl.close()
## Postconditions & return:
log.debug ('%s sequences remain after filtering ...' % filter_cnt)
return filtered_out_hndl.name
