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