Sebastian Haase wrote: >On Tuesday 19 September 2006 15:48, Travis Oliphant wrote: > > >>Sebastian Haase wrote: >> >> ><snip> > > >>>can we please change dtype to default to float64 !? >>> >>> >>The default is float64 now (as long as you are not using >>numpy.oldnumeric). >> >>I suppose more appropriately, we could reduce over float for integer >>data-types when calculating the mean as well (since a floating point is >>returned anyway). >> >> >> > >Is now mean() always "reducing over" float64 ? >The svn note """Log: >Fix mean, std, and var methods so that they reduce over double data-type with >integer inputs. >""" >makes it sound that a float32 input is stays float32 ? > > Yes, that is true. Only integer inputs are changed because you are going to get a floating point output anyway.
>For mean calculation this might introduce large errors - I usually would >require double-precision for *any* input type ... > > Of course. The system is not fool-proof. I hesitate to arbitrarily change this. The advantage of using single-precision calculation is that it is faster. We do rely on the user who expressly requests these things to be aware of the difficulties. >(don't know how to say this for complex types !? Are here real and imag >treated separately / independently ?) > > There is a complex add performed at a low-level as two separate adds. The addition is performed in the precision requested. -Travis ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion
