1
我想模擬一些dna-sequencing讀取,並且爲了加速代碼,我需要並行運行它。基本上,我想要做的是以下幾點:我從人類基因組中取樣讀取,並且我認爲從多處理模塊的兩個過程中的一個嘗試從相同的文件(人類基因組)中獲取數據進程被破壞,無法獲得所需的DNA序列。我嘗試過不同的事情,但我對並行編程非常陌生,並且我無法解決我的問題多進程,讀取同一文件的各種進程
當我使用一個內核運行腳本時,它工作正常。
這是我調用該函數
if __name__ == '__main__':
jobs = []
# init the processes
for i in range(number_of_cores):
length= 100
lock = mp.Manager().Lock()
p = mp.Process(target=simulations.sim_reads,args=(lock,FastaFile, "/home/inigo/msc_thesis/genome_data/hg38.fa",length,paired,results_dir,spawn_reads[i],temp_file_names[i]))
jobs.append(p)
p.start()
for p in jobs:
p.join()
的方式,這是我使用來獲取讀取功能,分別處理數據寫入到不同的文件。
def sim_single_end(lc,fastafile,chr,chr_pos_start,chr_pos_end,read_length, unique_id):
lc.acquire()
left_split_read = fastafile.fetch(chr, chr_pos_end - (read_length/2), chr_pos_end)
right_split_read = fastafile.fetch(chr, chr_pos_start, chr_pos_start + (read_length/2))
reversed_left_split_read = left_split_read[::-1]
total_read = reversed_left_split_read + right_split_read
seq_id = "id:%s-%s|left_pos:%s-%s|right:%s-%s " % (unique_id,chr, int(chr_pos_end - (read_length/2)), int(chr_pos_end), int(chr_pos_start),int(chr_pos_start + (read_length/2)))
quality = "I" * read_length
fastq_string = "@%s\n%s\n+\n%s\n" % (seq_id, total_read, quality)
lc.release()
new_record = SeqIO.read(StringIO(fastq_string), "fastq")
return(new_record)
這裏是回溯:
Traceback (most recent call last):
File "/usr/lib/python3.5/multiprocessing/process.py", line 249, in _bootstrap
self.run()
File "/usr/lib/python3.5/multiprocessing/process.py", line 93, in run
self._target(*self._args, **self._kwargs)
File "/home/inigo/Dropbox/PycharmProjects/circ_dna/simulations.py", line 107, in sim_ecc_reads
new_read = sim_single_end(lc,fastafile, chr, chr_pos_start, chr_pos_end, read_length, read_id)
File "/home/inigo/Dropbox/PycharmProjects/circ_dna/simulations.py", line 132, in sim_single_end
new_record = SeqIO.read(StringIO(fastq_string), "fastq")
File "/usr/local/lib/python3.5/dist-packages/Bio/SeqIO/__init__.py", line 664, in read
first = next(iterator)
File "/usr/local/lib/python3.5/dist-packages/Bio/SeqIO/__init__.py", line 600, in parse
for r in i:
File "/usr/local/lib/python3.5/dist-packages/Bio/SeqIO/QualityIO.py", line 1031, in FastqPhredIterator
for title_line, seq_string, quality_string in FastqGeneralIterator(handle):
File "/usr/local/lib/python3.5/dist-packages/Bio/SeqIO/QualityIO.py", line 951, in FastqGeneralIterator
% (title_line, seq_len, len(quality_string)))
ValueError: Lengths of sequence and quality values differs for id:6-chr1_KI270707v1_random|left_pos:50511537-50511587|right:50511214-50511264 (0 and 100).
您還沒有表現出回溯的錯誤。如果進程每次寫入不同的文件,則可以事先隨機化所有讀取的行(確保不重疊),將該塊列出並傳遞給每個進程。只要您阻止他們同時讀取文件,每個進程只會查看其預先分配的塊 – roganjosh
您已經包含了追蹤,除了錯誤本身。 – roganjosh
@roganjosh嗨!我添加了回溯。我試圖阻止他們用'Lock()'同時讀取文件。然而它沒有奏效。我應該如何防止他們同時讀取文件? – Praderas