Hi, 2011/10/31 Stéfan van der Walt <stefan@sun.ac.za>:
On Mon, Oct 31, 2011 at 11:23 AM, Matthew Brett <matthew.brett@gmail.com> wrote:
In [8]: np.float(2**63) == 2**63 Out[8]: True
In [9]: np.float(2**63) > 2**63-1 Out[9]: True
In [10]: np.float64(2**63) == 2**63 Out[10]: True
In [11]: np.float64(2**63) > 2**63-1 Out[11]: False
In [16]: np.float64(2**63-1) == np.float(2**63-1) Out[16]: True
Interesting. Turns out that np.float(x) returns a Python float object. If you change the experiment to only use numpy array scalars, things are more consistent:
In [36]: np.array(2**63, dtype=np.float) > 2**63 - 1 Out[36]: False
In [37]: np.array(2**63, dtype=np.float32) > 2**63 - 1 Out[37]: False
In [38]: np.array(2**63, dtype=np.float64) > 2**63 - 1
Oh, dear, I'm suffering now: In [11]: res = np.array((2**31,), dtype=np.float32) In [12]: res > 2**31-1 Out[12]: array([False], dtype=bool) OK - that's what I was expecting from the above, but now: In [13]: res[0] > 2**31-1 Out[13]: True In [14]: res[0].dtype Out[14]: dtype('float32') Sorry, maybe I'm not thinking straight, but I'm confused... See you, Matthew