[Numpy-discussion] Casting to np.byte before clearing values

2016-12-26 Thread Nicolas P. Rougier
Hi all, I'm trying to understand why viewing an array as bytes before clearing makes the whole operation faster. I imagine there is some kind of special treatment for byte arrays but I've no clue. # Native float Z_float = np.ones(100, float) Z_int = np.ones(100, int) %timeit Z_fl

Re: [Numpy-discussion] Casting to np.byte before clearing values

2016-12-26 Thread Sebastian Berg
On Mo, 2016-12-26 at 10:34 +0100, Nicolas P. Rougier wrote: > Hi all, > > > I'm trying to understand why viewing an array as bytes before > clearing makes the whole operation faster. > I imagine there is some kind of special treatment for byte arrays but > I've no clue.  > Sure, if its a 1-byte

Re: [Numpy-discussion] Casting to np.byte before clearing values

2016-12-26 Thread Nicolas P. Rougier
Thanks for the explanation Sebastian, makes sense. Nicolas > On 26 Dec 2016, at 11:48, Sebastian Berg wrote: > > On Mo, 2016-12-26 at 10:34 +0100, Nicolas P. Rougier wrote: >> Hi all, >> >> >> I'm trying to understand why viewing an array as bytes before >> clearing makes the whole operatio

Re: [Numpy-discussion] Casting to np.byte before clearing values

2016-12-26 Thread Benjamin Root
Might be os-specific, too. Some virtual memory management systems might special case the zeroing out of memory. Try doing the same thing with a different value than zero. On Dec 26, 2016 6:15 AM, "Nicolas P. Rougier" wrote: Thanks for the explanation Sebastian, makes sense. Nicolas > On 26 D

[Numpy-discussion] script for building numpy from source in virtualenv and outside it

2016-12-26 Thread Felipe Vieira
Dear fellows, I'm struggling with a single script to build numpy from source in a virtual env. I want the same script to be able to be run with a normal env. So if ran from a normal env it should affect all users. If ran within a virtual env the installation should be constrained to that env. I

Re: [Numpy-discussion] script for building numpy from source in virtualenv and outside it

2016-12-26 Thread Ralf Gommers
On Tue, Dec 27, 2016 at 9:43 AM, Felipe Vieira wrote: > Dear fellows, > > I'm struggling with a single script to build numpy from source in a > virtual env. I want the same script to be able to be run with a normal env. > > So if ran from a normal env it should affect all users. > If ran within a