Justin and Cedric: thank you for your suggestions. I removed all uses of `with-precision`; instead, I used various BigDecimal methods directly, such as .divide, .round, and .setScale by passing in a MathContext. Best I can tell (so far), this solved my problem.
On Monday, January 6, 2014 9:19:50 PM UTC-5, Cedric Greevey wrote: > > It's possibly an interaction between memoization and dynamic vars; more > specifically, a result might be being memoized with one with-precision > context active, and then recalled with a different one active, with > arguments that compare equal despite the different precisions (say, because > those arguments that are BigDecimals are exactly representable at the lower > of the two precisions). If the result is *not* the same at the higher > precision, that could cause an expected-equal check to fail in your test. > > I'd also wonder at possibly having a test work if it used a memoized > result generated earlier with a finite precision in effect, and fail with > ArithmeticException without the memoization if the test doesn't set a > precision limit itself and the result's not exactly representable at any > finite precision (e.g. 1/7); but this would likely result in a test that > worked in the suite and failed in isolation, instead of the reverse. > However, if high memory use is causing a memoized value computed at limited > precision to be "forgotten" and then recalculated with no precision limit, > that might trigger failures in the suite of tests that worked in isolation. > > In any event, subtle interaction of with-precision's underlying dynamic > var *math-context* with memoization is an obvious suspect worth > investigating, even if it might ultimately be acquitted by the jury. :) > > > > On Mon, Jan 6, 2014 at 1:21 PM, Justin Kramer <jkkr...@gmail.com<javascript:> > > wrote: > >> Shot in the dark: check that arguments passed to your memoized functions >> use consistent typing. A BigDecimal such as 1M does not necessarily equal 1 >> (a Long): >> >> > (= 1 1M) >> false >> > (== 1 1M) >> true >> >> Your memoized functions could be recomputing values unnecessarily if >> you're giving them different types of numbers. >> >> Justin >> >> >> On Monday, January 6, 2014 12:57:49 PM UTC-5, David James wrote: >>> >>> I've got a Clojure test suite that fails when run as whole but passes >>> when run piecemeal. This just started happening. I've tested the code >>> thoroughly. The bug pops up in a part of the code that I did not change. >>> So, at present, it feels like a heisenbug! >>> >>> These may be some relevant pieces: >>> * I'm using memoization; the failures happen in memoized functions. >>> * I'm doing a lot of various precision BigDecimal math. >>> >>> Some tentative guesses: >>> * Somehow one test is affecting another test >>> >>> Questions (there are speculative): >>> * What are some possible ways that memoization might fail (e.g. return >>> an incorrect value)? >>> * Is it possible that higher memory usage could cause memoization >>> results to get lost? >>> >>> Unfortunately, it is a sizable code base, and I don't have a small, >>> reproducible example. Any suggestions? >>> >>> -David >>> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clo...@googlegroups.com<javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com <javascript:> >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to clojure+u...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
