Question

我想加快一些分析天文数据所需的脚本。我有为每个单独的图像文件（以.fits文件格式）独立运行的脚本。我试图使用Multiprocessing.Pool()和地图一次启动多个文件。我的代码如下所示：

def sextract(name):
    # creates a class instance and calls the method
    astro = astrometry(name, *some_more_args)
    astro.sextract()

arguments = ['PART1_cal.fits', 'PART2_cal.fits', 'PART3_cal.fits',
            'PART4_cal.fits', 'PART5_cal.fits']

with closing(Pool()) as pool:
    pool.map(sextract, arguments)
    pool.terminate()

，astrometry.sextract方法如下所示：

def sextract(self):
    sex = 'sextractor'
    headerlist = ['JD-START', 'OBSERVER', 'DATE', 'TM-START', 'OBJECT',
                  'FLTRNAME', 'RA', 'DEC', 'AIRMASS',
                  'EXP_TIME']
    calib = self._from
    # calls the SourceExtrator in the shell with a config-file and
    # the file name
    os.system(sex + ' -c ' + self.sexpath + ' ' + calib)
    # copies the extracted file to a folder on an external HDD
    shutil.copy2(self.ext_path, self._to + '/' +
                 calib.split('/')[-1])
    # opens the old .fits image and extracts the header
    old = fits.open(calib)
    o = old[0].header
    # opens the new(copied) .fits image and extracts the header
    # this produces the error
    extr = fits.open(self._to + '/' + calib.split('/')[-1],
                     mode='update')                         
    e = extr[1].header
    # goes through the old header entries and copies all entries 
    # in the to the new header
    for g in headerlist:
        e[g] = o[g]
    # saves the new header to the new(copied) file and closes both 
    # files
    extr[1].header = e
    extr.flush()
    extr.close()
    old.close()

每次运行此代码时，我都会得到一个IOError: Header missing END card.，这是由我打开新.fits并将其放入变量extr的行所引发的。起初我认为这会发生，因为复制过程需要太长时间，并且python尝试在文件完成复制之前访问该文件。我插入time.sleep(10)来检查，但错误仍然出现。

我尝试使用pool.apply()和普通map()，在这两种情况下我都没有收到错误。使用pool.apply()时，map()的情况几乎和<select id="sltFont" onchange="changeFont(this.valueOf);"> <option selected disabled>Select a Font</option> <option value=”Arial” style="font-family:arial;">Arial</option> <option value=”Calibri” style="font-family:Calibri;">Calibri</option> <option value=”Candara” style="font-family:Candara;">Candara</option> <option value=”ComicSansMS” style="font-family:'Comic Sans MS';">Comic Sans MS</option> <option value=”FranklinGothicMedium” style="font-family:'Franklin Gothic Medium';">Franklin Gothic Medium</option> <option value=”FrenchScriptMT” style="font-family:'French Script MT';">French Script MT</option> <option value=”Impact” style="font-family:Impact;">Impact</option> <option value=”JuiceITC” style="font-family:'Juice ITC';">Juice ITC </option> <option value=”KristenITC” style="font-family:'Kristen ITC';">Kristen ITC</option> <option value=”LucidaHandwriting” style="font-family:'Lucida Handwriting';">Lucida Handwriting</option> </select>一样长，所以我还没有真正做到这一点。

我知道这是一个非常具体的问题，但我希望有人可能知道我的问题在哪里，或者已经有类似的工作了。

使用astropy时出现Python-Multiprocessing错误

0 个答案: