[Numpy-discussion] bug in ceil()

Charles R Harris charlesr.harris@gmail....
Wed Oct 6 13:10:50 CDT 2010


On Wed, Oct 6, 2010 at 11:55 AM, Christian Fischer <
cfischer@itm.uni-stuttgart.de> wrote:

> Hi All,
>
> I use numpy 1.4.1 on Debian squeeze amd64.
>
> I noticed that ceil() is not working properly.
>
> If the input to ceil() is a float I expect a float to be returned but for
> inputs
> in (-1.0, 0.0) the result is of type integer.
>
> In [65]: np.__version__
> Out[65]: '1.4.1'
>
> In [66]: np.ceil(-1.1)
> Out[66]: -1.0
>
> In [67]: np.ceil(-0.734)
> Out[67]: -0
>
> In [68]: np.ceil(-0.256)
> Out[68]: -0
>
> In [69]: np.ceil(-0.0)
> Out[69]: -0
>
> In [70]: np.ceil(0.2)
> Out[70]: 1.0
>
>
The -0 is a float type, you can't get it with integers. The printing might
could be tweaked to return -0.0, which would be less misleading. The thing
that bothers me is that -0 is returned instead of 0.0, but that can be
fixed.

In [2]: ceil(-.5)
Out[2]: -0

In [3]: ceil(-.5) + 0
Out[3]: 0.0

Please open a ticket, maybe two.

Chuck
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