Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newsfeed.xs4all.nl!newsfeed1.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.015 X-Spam-Evidence: '*H*': 0.97; '*S*': 0.00; '(of': 0.07; '22,': 0.09; 'subject:using': 0.09; 'valueerror:': 0.09; 'python': 0.11; 'itself.': 0.14; 'alpha,': 0.16; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'hmm.': 0.16; 'iterable,': 0.16; 'numpy': 0.16; 'operands': 0.16; 'subject:skip:m 10': 0.16; 'subject:when': 0.16; 'traverse': 0.16; 'wrote:': 0.18; 'appears': 0.22; 'error': 0.23; 'looks': 0.24; 'question': 0.24; 'skip:" 40': 0.26; 'code:': 0.26; 'header:In-Reply-To:1': 0.27; 'am,': 0.29; 'raise': 0.29; 'message-id:@mail.gmail.com': 0.30; "i'm": 0.30; 'file': 0.32; 'checked': 0.32; 'fri,': 0.33; 'there,': 0.34; 'could': 0.34; 'definition': 0.35; 'received:google.com': 0.35; 'there': 0.35; 'possible': 0.36; 'subject:?': 0.36; 'starting': 0.37; 'nov': 0.38; 'to:addr:python-list': 0.38; 'that,': 0.38; 'does': 0.39; 'though,': 0.39; 'to:addr:python.org': 0.39; 'how': 0.40; 'john': 0.61; "you're": 0.61; 'information': 0.63; 'map': 0.64; 'here': 0.66; 'broadcast': 0.68; 'evaluate': 0.72; '3.4': 0.84; '81,': 0.84; '2013': 0.98 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=spTVOmdP7Md49+TJvgyM0U2TBCo7/ILM3G+jHCWB+7A=; b=z2oqgOeHSTai2Qnvz0BIQ9Ga7W3L5pqNOFsodQ4x+s9QVlm2qtEfdMBGJkWyvyMjCh prSN1456h+ILAAbyZc5xumSOvZVhvlXNfUxZ0xQBRStAYraVkQxwV63K3hUxrU2V6f/+ OuuNK1apEJDT5IKA9iZ+m/fu4BpF6IEbrlmRBFDRq0EOrIHKKB5LS8CjnBDNrjTtakh8 veoWZUFb69ztq7rFIL32Z/DJ+l2gdN1BYzP1KMbYryMmB4OrEFoMFmlIRXMvcPwQq324 1h7fKJ2cikUZq7cR6u+t+SeBRf6yibjfh8W6YQj6cw9CHs0vcjui6CJWdX0dldLTDlsG 4T2A== MIME-Version: 1.0 X-Received: by 10.69.31.1 with SMTP id ki1mr7528283pbd.124.1385054673899; Thu, 21 Nov 2013 09:24:33 -0800 (PST) In-Reply-To: References: Date: Fri, 22 Nov 2013 04:24:33 +1100 Subject: Re: Traceback when using multiprocessing, less than helpful? From: Chris Angelico To: python-list@python.org Content-Type: text/plain; charset=ISO-8859-1 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 21 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1385054683 news.xs4all.nl 15913 [2001:888:2000:d::a6]:38760 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:60171 On Fri, Nov 22, 2013 at 4:01 AM, John Ladasky wrote: > Here is the end of the traceback, starting with the last line of my code: "result = pool.map(evaluate, bundles)". After that, I'm into Python itself. > > File ".../evaluate.py", line 81, in evaluate > result = pool.map(evaluate, bundles) > File "/usr/lib/python3.3/multiprocessing/pool.py", line 228, in map > return self._map_async(func, iterable, mapstar, chunksize).get() > File "/usr/lib/python3.3/multiprocessing/pool.py", line 564, in get > raise self._value > ValueError: operands could not be broadcast together with shapes (1,3) (4) > > Notice that no line of numpy appears in the traceback? Still, there are three things that make me think that this error is coming from numpy. Hmm. This looks like a possible need for the 'raise from' syntax. I just checked multiprocessing/pool.py from 3.4 alpha, and it has much what you're seeing there, in the definition of AsyncResult (of which MapResult is a subclass). The question is, though, how well does the information traverse the process boundary? ChrisA