Source code for deeptools.countReadsPerBin

import shutil
import os
import time
import sys
import multiprocessing
import numpy as np

# deepTools packages
import deeptools.utilities
from deeptools import bamHandler
from deeptools import mapReduce
from deeptoolsintervals import GTF
import pyBigWig

debug = 0
old_settings = np.seterr(all='ignore')

[docs] def countReadsInRegions_wrapper(args): """ Passes the arguments to countReadsInRegions_worker. This is a step required given the constrains from the multiprocessing module. The args var, contains as first element the 'self' value from the countReadsPerBin object """ return CountReadsPerBin.count_reads_in_region(*args)
[docs] class CountReadsPerBin(object): r"""Collects coverage over multiple bam files using multiprocessing This function collects read counts (coverage) from several bam files and returns an numpy array with the results. This class uses multiprocessing to compute the coverage. Parameters ---------- bamFilesList : list List containing the names of indexed bam files. E.g. ['file1.bam', 'file2.bam'] binLength : int Length of the window/bin. This value is overruled by ``bedFile`` if present. numberOfSamples : int Total number of samples. The genome is divided into ``numberOfSamples``, each with a window/bin length equal to ``binLength``. This value is overruled by ``stepSize`` in case such value is present and by ``bedFile`` in which case the number of samples and bins are defined in the bed file numberOfProcessors : int Number of processors to use. Default is 4 verbose : bool Output messages. Default: False region : str Region to limit the computation in the form chrom:start:end. bedFile : list of file_handles. Each file handle corresponds to a bed file containing the regions for which to compute the coverage. This option overrules ``binLength``, ``numberOfSamples`` and ``stepSize``. blackListFileName : str A string containing a BED file with blacklist regions. extendReads : bool, int Whether coverage should be computed for the extended read length (i.e. the region covered by the two mates or the regions expected to be covered by single-reads). If the value is 'int', then then this is interpreted as the fragment length to extend reads that are not paired. For Illumina reads, usual values are around 300. This value can be determined using the peak caller MACS2 or can be approximated by the fragment lengths computed when preparing the library for sequencing. If the value is of the variable is true and not value is given, the fragment size is sampled from the library but only if the library is paired-end. Default: False minMappingQuality : int Reads of a mapping quality less than the give value are not considered. Default: None ignoreDuplicates : bool Whether read duplicates (same start, end position. If paired-end, same start-end for mates) are to be excluded. Default: false chrToSkip: list List with names of chromosomes that do not want to be included in the coverage computation. This is useful to remove unwanted chromosomes (e.g. 'random' or 'Het'). stepSize : int the positions for which the coverage is computed are defined as follows: ``range(start, end, stepSize)``. Thus, a stepSize of 1, will compute the coverage at each base pair. If the stepSize is equal to the binLength then the coverage is computed for consecutive bins. If seepSize is smaller than the binLength, then teh bins will overlap. center_read : bool Determines if reads should be centered with respect to the fragment length. samFlag_include : int Extracts only those reads having the SAM flag. For example, to get only reads that are the first mates a samFlag of 64 could be used. Similarly, the samFlag_include can be used to select only reads mapping on the reverse strand or to get only properly paired reads. samFlag_exclude : int Removes reads that match the SAM flag. For example to get all reads that map to the forward strand a samFlag_exlude 16 should be used. Which translates into exclude all reads that map to the reverse strand. zerosToNans : bool If true, zero values encountered are transformed to Nans. Default false. skipZeroOverZero : bool If true, skip bins where all input BAM files have no coverage (only applicable to bamCompare). minFragmentLength : int If greater than 0, fragments below this size are excluded. maxFragmentLength : int If greater than 0, fragments above this size are excluded. out_file_for_raw_data : str File name to save the raw counts computed statsList : list For each BAM file in bamFilesList, the associated per-chromosome statistics returned by openBam mappedList : list For each BAM file in bamFilesList, the number of mapped reads in the file. bed_and_bin : boolean If true AND a bedFile is given, compute coverage of each bin of the given size in each region of bedFile genomeChunkSize : int If not None, the length of the genome used for multiprocessing. Returns ------- numpy array Each row correspond to each bin/bed region and each column correspond to each of the bamFiles. Examples -------- The test data contains reads for 200 bp. >>> test = Tester() The transpose function is used to get a nicer looking output. The first line corresponds to the number of reads per bin in bam file 1 >>> c = CountReadsPerBin([test.bamFile1, test.bamFile2], 50, 4) >>> np.transpose( array([[0., 0., 1., 1.], [0., 1., 1., 2.]]) """ def __init__(self, bamFilesList, binLength=50, numberOfSamples=None, numberOfProcessors=1, verbose=False, region=None, bedFile=None, extendReads=False, genomeChunkSize=None, blackListFileName=None, minMappingQuality=None, ignoreDuplicates=False, chrsToSkip=[], stepSize=None, center_read=False, samFlag_include=None, samFlag_exclude=None, zerosToNans=False, skipZeroOverZero=False, smoothLength=0, minFragmentLength=0, maxFragmentLength=0, out_file_for_raw_data=None, bed_and_bin=False, statsList=[], mappedList=[]): self.bamFilesList = bamFilesList self.binLength = binLength self.numberOfSamples = numberOfSamples self.blackListFileName = blackListFileName self.statsList = statsList self.mappedList = mappedList self.skipZeroOverZero = skipZeroOverZero self.bed_and_bin = bed_and_bin self.genomeChunkSize = genomeChunkSize if extendReads and len(bamFilesList): from deeptools.getFragmentAndReadSize import get_read_and_fragment_length frag_len_dict, read_len_dict = get_read_and_fragment_length(bamFilesList[0], return_lengths=False, blackListFileName=blackListFileName, numberOfProcessors=numberOfProcessors, verbose=verbose) if extendReads is True: # try to guess fragment length if the bam file contains paired end reads if frag_len_dict: self.defaultFragmentLength = int(frag_len_dict['median']) else: exit("*ERROR*: library is not paired-end. Please provide an extension length.") if verbose: print(("Fragment length based on paired en data " "estimated to be {}".format(frag_len_dict['median']))) elif extendReads < read_len_dict['median']: sys.stderr.write("*WARNING*: read extension is smaller than read length (read length = {}). " "Reads will not be extended.\n".format(int(read_len_dict['median']))) self.defaultFragmentLength = 'read length' elif extendReads > 2000: exit("*ERROR*: read extension must be smaller that 2000. Value give: {} ".format(extendReads)) else: self.defaultFragmentLength = int(extendReads) else: self.defaultFragmentLength = 'read length' self.numberOfProcessors = numberOfProcessors self.verbose = verbose self.region = region self.bedFile = bedFile self.minMappingQuality = minMappingQuality self.ignoreDuplicates = ignoreDuplicates self.chrsToSkip = chrsToSkip self.stepSize = stepSize self.center_read = center_read self.samFlag_include = samFlag_include self.samFlag_exclude = samFlag_exclude self.minFragmentLength = minFragmentLength self.maxFragmentLength = maxFragmentLength self.zerosToNans = zerosToNans self.smoothLength = smoothLength if out_file_for_raw_data: self.save_data = True self.out_file_for_raw_data = out_file_for_raw_data else: self.save_data = False self.out_file_for_raw_data = None # check that wither numberOfSamples or stepSize are set if numberOfSamples is None and stepSize is None and bedFile is None: raise ValueError("either stepSize, numberOfSamples or bedFile have to be set") if self.defaultFragmentLength != 'read length': self.maxPairedFragmentLength = 4 * self.defaultFragmentLength else: self.maxPairedFragmentLength = 1000 if self.maxFragmentLength > 0: self.maxPairedFragmentLength = self.maxFragmentLength if len(self.mappedList) == 0: try: for fname in self.bamFilesList: bam, mapped, unmapped, stats = bamHandler.openBam(fname, returnStats=True, nThreads=self.numberOfProcessors) self.mappedList.append(mapped) self.statsList.append(stats) bam.close() except: self.mappedList = [] self.statsList = []
[docs] def get_chunk_length(self, bamFilesHandles, genomeSize, chromSizes, chrLengths): # Try to determine an optimal fraction of the genome (chunkSize) that is sent to # workers for analysis. If too short, too much time is spent loading the files # if too long, some processors end up free. # the following values are empirical if self.stepSize is None: if self.region is None: self.stepSize = max(int(float(genomeSize) / self.numberOfSamples), 1) else: # compute the step size, based on the number of samples # and the length of the region studied (chrom, start, end) = mapReduce.getUserRegion(chromSizes, self.region)[:3] self.stepSize = max(int(float(end - start) / self.numberOfSamples), 1) # number of samples is better if large if np.mean(chrLengths) < self.stepSize and self.bedFile is None: min_num_of_samples = int(genomeSize / np.mean(chrLengths)) raise ValueError("numberOfSamples has to be bigger than {} ".format(min_num_of_samples)) max_mapped = 0 if len(self.mappedList) > 0: max_mapped = max(self.mappedList) # If max_mapped is 0 (i.e., bigWig input), set chunkSize to a multiple of binLength and use every bin if max_mapped == 0: chunkSize = 10000 * self.binLength self.stepSize = self.binLength else: reads_per_bp = float(max_mapped) / genomeSize chunkSize = int(self.stepSize * 1e3 / (reads_per_bp * len(bamFilesHandles))) # Ensure that chunkSize is always at least self.stepSize if chunkSize < self.stepSize: chunkSize = self.stepSize # Ensure that chunkSize is always at least self.binLength if self.binLength and chunkSize < self.binLength: chunkSize = self.binLength return chunkSize
[docs] def run(self, allArgs=None): bamFilesHandles = [] for x in self.bamFilesList: try: y = bamHandler.openBam(x) except SystemExit: sys.exit(sys.exc_info()[1]) except: y = bamFilesHandles.append(y) chromsizes, non_common = deeptools.utilities.getCommonChrNames(bamFilesHandles, verbose=self.verbose) # skip chromosome in the list. This is usually for the # X chromosome which may have either one copy in a male sample # or a mixture of male/female and is unreliable. # Also the skip may contain heterochromatic regions and # mitochondrial DNA if len(self.chrsToSkip): chromsizes = [x for x in chromsizes if x[0] not in self.chrsToSkip] chrNames, chrLengths = list(zip(*chromsizes)) genomeSize = sum(chrLengths) chunkSize = None if self.bedFile is None: if self.genomeChunkSize is None: chunkSize = self.get_chunk_length(bamFilesHandles, genomeSize, chromsizes, chrLengths) else: chunkSize = self.genomeChunkSize [bam_h.close() for bam_h in bamFilesHandles] if self.verbose: print("step size is {}".format(self.stepSize)) if self.region: # in case a region is used, append the tilesize self.region += ":{}".format(self.binLength) # Handle GTF options transcriptID, exonID, transcript_id_designator, keepExons = deeptools.utilities.gtfOptions(allArgs) # use map reduce to call countReadsInRegions_wrapper imap_res = mapReduce.mapReduce([], countReadsInRegions_wrapper, chromsizes, self_=self, genomeChunkLength=chunkSize, bedFile=self.bedFile, blackListFileName=self.blackListFileName, region=self.region, numberOfProcessors=self.numberOfProcessors, transcriptID=transcriptID, exonID=exonID, keepExons=keepExons, transcript_id_designator=transcript_id_designator) if self.out_file_for_raw_data: if len(non_common): sys.stderr.write("*Warning*\nThe resulting bed file does not contain information for " "the chromosomes that were not common between the bigwig files\n") # concatenate intermediary bedgraph files ofile = open(self.out_file_for_raw_data, "w") for _values, tempFileName in imap_res: if tempFileName: # concatenate all intermediate tempfiles into one _foo = open(tempFileName, 'r') shutil.copyfileobj(_foo, ofile) _foo.close() os.remove(tempFileName) ofile.close() try: num_reads_per_bin = np.concatenate([x[0] for x in imap_res], axis=0) return num_reads_per_bin except ValueError: if self.bedFile: sys.exit('\nNo coverage values could be computed.\n\n' 'Please check that the chromosome names in the BED file are found on the bam files.\n\n' 'The valid chromosome names are:\n{}'.format(chrNames)) else: sys.exit('\nNo coverage values could be computed.\n\nCheck that all bam files are valid and ' 'contain mapped reads.')
[docs] def count_reads_in_region(self, chrom, start, end, bed_regions_list=None): """Counts the reads in each bam file at each 'stepSize' position within the interval (start, end) for a window or bin of size binLength. The stepSize controls the distance between bins. For example, a step size of 20 and a bin size of 20 will create bins next to each other. If the step size is smaller than the bin size the bins will overlap. If a list of bedRegions is given, then the number of reads that overlaps with each region is counted. Parameters ---------- chrom : str Chrom name start : int start coordinate end : int end coordinate bed_regions_list: list List of list of tuples of the form (start, end) corresponding to bed regions to be processed. If not bed file was passed to the object constructor then this list is empty. Returns ------- numpy array The result is a numpy array that as rows each bin and as columns each bam file. Examples -------- Initialize some useful values >>> test = Tester() >>> c = CountReadsPerBin([test.bamFile1, test.bamFile2], 25, 0, stepSize=50) The transpose is used to get better looking numbers. The first line corresponds to the number of reads per bin in the first bamfile. >>> _array, __ = c.count_reads_in_region(test.chrom, 0, 200) >>> _array array([[0., 0.], [0., 1.], [1., 1.], [1., 2.]]) """ if start > end: raise NameError("start %d bigger that end %d" % (start, end)) if self.stepSize is None and bed_regions_list is None: raise ValueError("stepSize is not set!") # array to keep the read counts for the regions subnum_reads_per_bin = [] start_time = time.time() bam_handles = [] for fname in self.bamFilesList: try: bam_handles.append(bamHandler.openBam(fname)) except SystemExit: sys.exit(sys.exc_info()[1]) except: bam_handles.append( blackList = None if self.blackListFileName is not None: blackList = GTF(self.blackListFileName) # A list of lists of tuples transcriptsToConsider = [] if bed_regions_list is not None: if self.bed_and_bin: transcriptsToConsider.append([(x[1][0][0], x[1][0][1], self.binLength) for x in bed_regions_list]) else: transcriptsToConsider = [x[1] for x in bed_regions_list] else: if self.stepSize == self.binLength: transcriptsToConsider.append([(start, end, self.binLength)]) else: for i in range(start, end, self.stepSize): if i + self.binLength > end: break if blackList is not None and blackList.findOverlaps(chrom, i, i + self.binLength): continue transcriptsToConsider.append([(i, i + self.binLength)]) if self.save_data: _file = open(deeptools.utilities.getTempFileName(suffix='.bed'), 'w+t') _file_name = else: _file_name = '' for bam in bam_handles: for trans in transcriptsToConsider: tcov = self.get_coverage_of_region(bam, chrom, trans) if bed_regions_list is not None and not self.bed_and_bin: subnum_reads_per_bin.append(np.sum(tcov)) else: subnum_reads_per_bin.extend(tcov) subnum_reads_per_bin = np.concatenate([subnum_reads_per_bin]).reshape(-1, len(self.bamFilesList), order='F') if self.save_data: idx = 0 for i, trans in enumerate(transcriptsToConsider): if len(trans[0]) != 3: starts = ",".join([str(x[0]) for x in trans]) ends = ",".join([str(x[1]) for x in trans]) _file.write("\t".join([chrom, starts, ends]) + "\t") _file.write("\t".join(["{}".format(x) for x in subnum_reads_per_bin[i, :]]) + "\n") else: for exon in trans: for startPos in range(exon[0], exon[1], exon[2]): if idx >= subnum_reads_per_bin.shape[0]: # At the end of chromosomes (or due to blacklisted regions), there are bins smaller than the bin size # Counts there are added to the bin before them, but range() will still try to include them. break _file.write("{0}\t{1}\t{2}\t".format(chrom, startPos, min(startPos + exon[2], exon[1]))) _file.write("\t".join(["{}".format(x) for x in subnum_reads_per_bin[idx, :]]) + "\n") idx += 1 _file.close() if self.verbose: endTime = time.time() rows = subnum_reads_per_bin.shape[0] print("%s countReadsInRegions_worker: processing %d " "(%.1f per sec) @ %s:%s-%s" % (multiprocessing.current_process().name, rows, rows / (endTime - start_time), chrom, start, end)) return subnum_reads_per_bin, _file_name
[docs] def get_coverage_of_region(self, bamHandle, chrom, regions, fragmentFromRead_func=None): """ Returns a numpy array that corresponds to the number of reads that overlap with each tile. >>> test = Tester() >>> import pysam >>> c = CountReadsPerBin([], stepSize=1, extendReads=300) For this case the reads are length 36. The number of overlapping read fragments is 4 and 5 for the positions tested. >>> c.get_coverage_of_region(pysam.AlignmentFile(test.bamFile_PE), 'chr2', ... [(5000833, 5000834), (5000834, 5000835)]) array([4., 5.]) In the following example a paired read is extended to the fragment length which is 100 The first mate starts at 5000000 and the second at 5000064. Each mate is extended to the fragment length *independently* At position 500090-500100 one fragment of length 100 overlap, and after position 5000101 there should be zero reads. >>> c.zerosToNans = True >>> c.get_coverage_of_region(pysam.AlignmentFile(test.bamFile_PE), 'chr2', ... [(5000090, 5000100), (5000100, 5000110)]) array([ 1., nan]) In the following case the reads length is 50. Reads are not extended. >>> c.extendReads=False >>> c.get_coverage_of_region(pysam.AlignmentFile(test.bamFile2), '3R', [(148, 150), (150, 152), (152, 154)]) array([1., 2., 2.]) """ if not fragmentFromRead_func: fragmentFromRead_func = self.get_fragment_from_read nbins = len(regions) if len(regions[0]) == 3: nbins = 0 for reg in regions: nbins += (reg[1] - reg[0]) // reg[2] if (reg[1] - reg[0]) % reg[2] > 0: nbins += 1 coverages = np.zeros(nbins, dtype='float64') if self.defaultFragmentLength == 'read length': extension = 0 else: extension = self.maxPairedFragmentLength blackList = None if self.blackListFileName is not None: blackList = GTF(self.blackListFileName) vector_start = 0 for idx, reg in enumerate(regions): if len(reg) == 3: tileSize = int(reg[2]) nRegBins = (reg[1] - reg[0]) // tileSize if (reg[1] - reg[0]) % tileSize > 0: # Don't eliminate small bins! Issue 887 nRegBins += 1 else: nRegBins = 1 tileSize = int(reg[1] - reg[0]) # Blacklisted regions have a coverage of 0 if blackList and blackList.findOverlaps(chrom, reg[0], reg[1]): continue regStart = int(max(0, reg[0] - extension)) regEnd = reg[1] + int(extension) # If alignments are extended and there's a blacklist, ensure that no # reads originating in a blacklist are fetched if blackList and reg[0] > 0 and extension > 0: o = blackList.findOverlaps(chrom, regStart, reg[0]) if o is not None and len(o) > 0: regStart = o[-1][1] o = blackList.findOverlaps(chrom, reg[1], regEnd) if o is not None and len(o) > 0: regEnd = o[0][0] start_time = time.time() # caching seems faster. TODO: profile the function c = 0 if chrom not in bamHandle.references: raise NameError("chromosome {} not found in bam file".format(chrom)) prev_pos = set() lpos = None # of previous processed read pair for read in bamHandle.fetch(chrom, regStart, regEnd): if read.is_unmapped: continue if self.minMappingQuality and read.mapq < self.minMappingQuality: continue # filter reads based on SAM flag if self.samFlag_include and read.flag & self.samFlag_include != self.samFlag_include: continue if self.samFlag_exclude and read.flag & self.samFlag_exclude != 0: continue # Fragment lengths tLen = deeptools.utilities.getTLen(read) if self.minFragmentLength > 0 and tLen < self.minFragmentLength: continue if self.maxFragmentLength > 0 and tLen > self.maxFragmentLength: continue # get rid of duplicate reads that have same position on each of the # pairs if self.ignoreDuplicates: # Assuming more or less concordant reads, use the fragment bounds, otherwise the start positions if tLen >= 0: s = read.pos e = s + tLen else: s = read.pnext e = s - tLen if read.reference_id != read.next_reference_id: e = read.pnext if lpos is not None and lpos == read.reference_start \ and (s, e, read.next_reference_id, read.is_reverse) in prev_pos: continue if lpos != read.reference_start: prev_pos.clear() lpos = read.reference_start prev_pos.add((s, e, read.next_reference_id, read.is_reverse)) # since reads can be split (e.g. RNA-seq reads) each part of the # read that maps is called a position block. try: position_blocks = fragmentFromRead_func(read) except TypeError: # the get_fragment_from_read functions returns None in some cases. # Those cases are to be skipped, hence the continue line. continue last_eIdx = None for fragmentStart, fragmentEnd in position_blocks: if fragmentEnd is None or fragmentStart is None: continue fragmentLength = fragmentEnd - fragmentStart if fragmentLength == 0: continue # skip reads that are not in the region being # evaluated. if fragmentEnd <= reg[0] or fragmentStart >= reg[1]: continue if fragmentStart < reg[0]: fragmentStart = reg[0] if fragmentEnd > reg[0] + len(coverages) * tileSize: fragmentEnd = reg[0] + len(coverages) * tileSize sIdx = vector_start + max((fragmentStart - reg[0]) // tileSize, 0) eIdx = vector_start + min(np.ceil(float(fragmentEnd - reg[0]) / tileSize).astype('int'), nRegBins) if last_eIdx is not None: sIdx = max(last_eIdx, sIdx) if sIdx >= eIdx: continue sIdx = int(sIdx) eIdx = int(eIdx) coverages[sIdx:eIdx] += 1 last_eIdx = eIdx c += 1 if self.verbose: endTime = time.time() print("%s, processing %s (%.1f per sec) reads @ %s:%s-%s" % ( multiprocessing.current_process().name, c, c / (endTime - start_time), chrom, reg[0], reg[1])) vector_start += nRegBins # change zeros to NAN if self.zerosToNans: coverages[coverages == 0] = np.nan return coverages
[docs] def getReadLength(self, read): return len(read)
[docs] @staticmethod def is_proper_pair(read, maxPairedFragmentLength): """ Checks if a read is proper pair meaning that both mates are facing each other and are in the same chromosome and are not to far away. The sam flag for proper pair can not always be trusted. Note that if the fragment size is > maxPairedFragmentLength (~2kb usually) that False will be returned. :return: bool >>> import pysam >>> import os >>> from deeptools.countReadsPerBin import CountReadsPerBin as cr >>> root = os.path.dirname(os.path.abspath(__file__)) + "/test/test_data/" >>> bam = pysam.AlignmentFile("{}/test_proper_pair_filtering.bam".format(root)) >>> iter = bam.fetch() >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "keep" read True >>> cr.is_proper_pair(read, 200) # "keep" read, but maxPairedFragmentLength is too short False >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "improper pair" False >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "mismatch chr" False >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "same orientation1" False >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "same orientation2" False >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "rev first" False >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "rev first OK" True >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "for first" False >>> read = next(iter) >>> cr.is_proper_pair(read, 1000) # "for first" True """ if not read.is_proper_pair: return False if read.reference_id != read.next_reference_id: return False if abs(read.template_length) > maxPairedFragmentLength: return False # check that the mates face each other (inward) if read.is_reverse is read.mate_is_reverse: return False if read.is_reverse: if read.reference_start >= read.next_reference_start: return True else: if read.reference_start <= read.next_reference_start: return True return False
[docs] def get_fragment_from_read(self, read): """Get read start and end position of a read. If given, the reads are extended as follows: If reads are paired end, each read mate is extended to match the fragment length, otherwise, a default fragment length is used. If reads are split (give by the CIGAR string) then the multiple positions of the read are returned. When reads are extended the cigar information is skipped. Parameters ---------- read: pysam object. The following values are defined (for forward reads):: |-- -- read.tlen -- --| |-- read.alen --| -----|===============>------------<==============|---- | | | read.reference_start read.reference_end read.pnext and for reverse reads |-- -- read.tlen -- --| |-- read.alen --| -----|===============>-----------<===============|---- | | | read.pnext read.reference_start read.reference_end this is a sketch of a pair-end reads The function returns the fragment start and end, either using the paired end information (if available) or extending the read in the appropriate direction if this is single-end. Parameters ---------- read : pysam read object Returns ------- list of tuples [(fragment start, fragment end)] >>> test = Tester() >>> c = CountReadsPerBin([], 1, 1, 200, extendReads=True) >>> c.defaultFragmentLength=100 >>> c.get_fragment_from_read(test.getRead("paired-forward")) [(5000000, 5000100)] >>> c.get_fragment_from_read(test.getRead("paired-reverse")) [(5000000, 5000100)] >>> c.defaultFragmentLength = 200 >>> c.get_fragment_from_read(test.getRead("single-forward")) [(5001491, 5001691)] >>> c.get_fragment_from_read(test.getRead("single-reverse")) [(5001536, 5001736)] >>> c.defaultFragmentLength = 'read length' >>> c.get_fragment_from_read(test.getRead("single-forward")) [(5001491, 5001527)] >>> c.defaultFragmentLength = 'read length' >>> c.extendReads = False >>> c.get_fragment_from_read(test.getRead("paired-forward")) [(5000000, 5000036)] Tests for read centering. >>> c = CountReadsPerBin([], 1, 1, 200, extendReads=True, center_read=True) >>> c.defaultFragmentLength = 100 >>> assert c.get_fragment_from_read(test.getRead("paired-forward")) == [(5000032, 5000068)] >>> c.defaultFragmentLength = 200 >>> assert c.get_fragment_from_read(test.getRead("single-reverse")) == [(5001618, 5001654)] """ # if no extension is needed, use pysam get_blocks # to identify start and end reference positions. # get_blocks return a list of start and end positions # based on the CIGAR if skipped regions are found. # E.g for a cigar of 40M260N22M # get blocks return two elements for the first 40 matches # and the for the last 22 matches. if self.defaultFragmentLength == 'read length': return read.get_blocks() else: if self.is_proper_pair(read, self.maxPairedFragmentLength): if read.is_reverse: fragmentStart = read.next_reference_start fragmentEnd = read.reference_end else: fragmentStart = read.reference_start # the end of the fragment is defined as # the start of the forward read plus the insert length fragmentEnd = read.reference_start + abs(read.template_length) # Extend using the default fragment length else: if read.is_reverse: fragmentStart = read.reference_end - self.defaultFragmentLength fragmentEnd = read.reference_end else: fragmentStart = read.reference_start fragmentEnd = read.reference_start + self.defaultFragmentLength if self.center_read: fragmentCenter = fragmentEnd - (fragmentEnd - fragmentStart) / 2 fragmentStart = int(fragmentCenter - read.infer_query_length(always=False) / 2) fragmentEnd = fragmentStart + read.infer_query_length(always=False) assert fragmentStart < fragmentEnd, "fragment start greater than fragment" \ "end for read {}".format(read.query_name) return [(fragmentStart, fragmentEnd)]
[docs] def getSmoothRange(self, tileIndex, tileSize, smoothRange, maxPosition): """ Given a tile index position and a tile size (length), return the a new indices over a larger range, called the smoothRange. This region is centered in the tileIndex an spans on both sizes to cover the smoothRange. The smoothRange is trimmed in case it is less than zero or greater than maxPosition :: ---------------|==================|------------------ tileStart |--------------------------------------| | <-- smoothRange --> | | tileStart - (smoothRange-tileSize)/2 Test for a smooth range that spans 3 tiles. Examples -------- >>> c = CountReadsPerBin([], 1, 1, 1, 0) >>> c.getSmoothRange(5, 1, 3, 10) (4, 7) Test smooth range truncated on start. >>> c.getSmoothRange(0, 10, 30, 200) (0, 2) Test smooth range truncated on start. >>> c.getSmoothRange(1, 10, 30, 4) (0, 3) Test smooth range truncated on end. >>> c.getSmoothRange(5, 1, 3, 5) (4, 5) Test smooth range not multiple of tileSize. >>> c.getSmoothRange(5, 10, 24, 10) (4, 6) """ smoothTiles = int(smoothRange / tileSize) if smoothTiles == 1: return (tileIndex, tileIndex + 1) smoothTilesSide = float(smoothTiles - 1) / 2 smoothTilesLeft = int(np.ceil(smoothTilesSide)) smoothTilesRight = int(np.floor(smoothTilesSide)) + 1 indexStart = max(tileIndex - smoothTilesLeft, 0) indexEnd = min(maxPosition, tileIndex + smoothTilesRight) return (indexStart, indexEnd)
[docs] def remove_row_of_zeros(matrix): # remove rows containing all zeros or all nans _mat = np.nan_to_num(matrix) to_keep = _mat.sum(1) != 0 return matrix[to_keep, :]
[docs] def estimateSizeFactors(m): """ Compute size factors in the same way as DESeq2. The inverse of that is returned, as it's then compatible with bamCoverage. m : a numpy ndarray >>> m = np.array([[0, 1, 2], [3, 4, 5], [6, 7, 8], [0, 10, 0], [10, 5, 100]]) >>> sf = estimateSizeFactors(m) >>> assert np.all(np.abs(sf - [1.305, 0.9932, 0.783]) < 1e-4) >>> m = np.array([[0, 0], [0, 1], [1, 1], [1, 2]]) >>> sf = estimateSizeFactors(m) >>> assert np.all(np.abs(sf - [1.1892, 0.8409]) < 1e-4) """ loggeomeans = np.sum(np.log(m), axis=1) / m.shape[1] # Mask after computing the geometric mean m = <= 0, m) loggeomeans =, loggeomeans) # DESeq2 ratio-based size factor sf = np.exp( - loggeomeans).T, axis=0)) return 1. / sf
[docs] class Tester(object): def __init__(self): """ The distribution of reads between the two bam files is as follows. They cover 200 bp 0 100 200 |------------------------------------------------------------| A =============== =============== B =============== =============== =============== =============== """ self.root = os.path.dirname(os.path.abspath(__file__)) + "/test/test_data/" # self.root = "./test/test_data/" self.bamFile1 = self.root + "testA.bam" self.bamFile2 = self.root + "testB.bam" self.bamFile_PE = self.root + "test_paired2.bam" self.chrom = '3R' global debug debug = 0
[docs] def getRead(self, readType): """ prepare arguments for test """ bam = bamHandler.openBam(self.bamFile_PE) if readType == 'paired-reverse': read = [x for x in bam.fetch('chr2', 5000081, 5000082)][0] elif readType == 'single-forward': read = [x for x in bam.fetch('chr2', 5001491, 5001492)][0] elif readType == 'single-reverse': read = [x for x in bam.fetch('chr2', 5001700, 5001701)][0] else: # by default a forward paired read is returned read = [x for x in bam.fetch('chr2', 5000027, 5000028)][0] return read