Re: [Numpy-discussion] fast duplicate of array

2010-01-23 Thread Alan G Isaac
On 1/23/2010 7:29 PM, Anne Archibald wrote: > I had in mind accessing the underlying data through views > that were flat: > > In [3]: x = np.random.random((1000,1000)) > > In [4]: y = np.random.random((1000,1000)) > > In [5]: xf = x.view() > > In [6]: xf.shape = (-1,) > > In [7]: yf = y.view() > >

Re: [Numpy-discussion] fast duplicate of array

2010-01-23 Thread Alan G Isaac
On 1/23/2010 6:00 PM, Keith Goodman wrote: > x = y.view() Thanks, but I'm not looking for a view. And I need x to own its data. Alan ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion

Re: [Numpy-discussion] fast duplicate of array

2010-01-23 Thread Anne Archibald
2010/1/23 Alan G Isaac : > On 1/23/2010 5:01 PM, Anne Archibald wrote: >> If both arrays are "C contiguous", or more generally contiguous blocks >> of memory with the same strided structure, you might get faster >> copying by flattening them first, so that it can go in a single >> memcpy(). > > I m

Re: [Numpy-discussion] fast duplicate of array

2010-01-23 Thread Charles R Harris
On Sat, Jan 23, 2010 at 4:00 PM, Keith Goodman wrote: > On Sat, Jan 23, 2010 at 2:31 PM, Alan G Isaac wrote: > > On 1/23/2010 5:01 PM, Anne Archibald wrote: > >> If both arrays are "C contiguous", or more generally contiguous blocks > >> of memory with the same strided structure, you might get f

Re: [Numpy-discussion] fast duplicate of array

2010-01-23 Thread Keith Goodman
On Sat, Jan 23, 2010 at 2:31 PM, Alan G Isaac wrote: > On 1/23/2010 5:01 PM, Anne Archibald wrote: >> If both arrays are "C contiguous", or more generally contiguous blocks >> of memory with the same strided structure, you might get faster >> copying by flattening them first, so that it can go in

Re: [Numpy-discussion] fast duplicate of array

2010-01-23 Thread Alan G Isaac
On 1/23/2010 5:01 PM, Anne Archibald wrote: > If both arrays are "C contiguous", or more generally contiguous blocks > of memory with the same strided structure, you might get faster > copying by flattening them first, so that it can go in a single > memcpy(). I may misuderstand this. Did you jus

Re: [Numpy-discussion] fast duplicate of array

2010-01-23 Thread Anne Archibald
2010/1/23 Alan G Isaac : > Suppose x and y are conformable 2d arrays. > I now want x to become a duplicate of y. > I could create a new array: > x = y.copy() > or I could assign the values of y to x: > x[:,:] = y > > As expected the latter is faster (no array creation). > Are there better ways? If

[Numpy-discussion] random v. random_state in RandomState

2010-01-23 Thread Alan G Isaac
As I understand it, numpy.random provides the function ``random`` as an alias for ``random_state``. Might this be moved into numpy.random.mtrand.RandomState, for interface consistency? Right now if I start with ``prng = np.random.RandomState(seed=myseed)`` I cannot use ``prng.random`` as it does

[Numpy-discussion] fast duplicate of array

2010-01-23 Thread Alan G Isaac
Suppose x and y are conformable 2d arrays. I now want x to become a duplicate of y. I could create a new array: x = y.copy() or I could assign the values of y to x: x[:,:] = y As expected the latter is faster (no array creation). Are there better ways? Thanks, Alan Isaac _

Re: [Numpy-discussion] fromfile() for reading text (one more time!)

2010-01-23 Thread josef . pktd
On Sat, Jan 23, 2010 at 1:53 PM, Christopher Barker wrote: > a...@ajackson.org wrote: >> it doesn't support the reasonable >> (IMHO) behavior of treating quote delimited strings in the input file as a >> single field. > > I'd use the csv module for that. > > Which makes me wonder if it might make

Re: [Numpy-discussion] fromfile() for reading text (one more time!)

2010-01-23 Thread Christopher Barker
a...@ajackson.org wrote: > it doesn't support the reasonable > (IMHO) behavior of treating quote delimited strings in the input file as a > single field. I'd use the csv module for that. Which makes me wonder if it might make sense to build some of the numpy table-reading stuff on top of it...

Re: [Numpy-discussion] fromfile() for reading text (one more time!)

2010-01-23 Thread alan
>On Mon, Jan 4, 2010 at 10:39 PM, wrote: >>>Hi folks, >>> >>>I'm taking a look once again at fromfile() for reading text files. I >>>often have the need to read a LOT of numbers form a text file, and it >>>can actually be pretty darn slow do i the normal python way: >>> .big s