Re: [Numpy-discussion] Fast Reading of ASCII files

2011-12-12 Thread Chris.Barker
On 12/11/11 8:40 AM, Ralf Gommers wrote: On Wed, Dec 7, 2011 at 7:50 PM, Chris.Barker chris.bar...@noaa.gov * If we have a good, fast ascii (or unicode?) to array reader, hopefully it could be leveraged for use in the more complex cases. So that rather than genfromtxt() being

Re: [Numpy-discussion] Problem with using PyArray_AsCArray

2011-12-09 Thread Chris.Barker
On 12/9/11 11:25 AM, Ng, Enrico wrote: I am trying to pass a multi-dimensional ndarray to C as a multi-dimensional C array for the purposes of passing it to mathematica. I am using PyArray_AsCArray but getting an error. I understand that SWIG, Boost, et. al are perhaps too heavyweight for

[Numpy-discussion] Fast Reading of ASCII files

2011-12-07 Thread Chris.Barker
Hi folks, This is a continuation of a conversation already started, but i gave it a new, more appropriate, thread and subject. On 12/6/11 2:13 PM, Wes McKinney wrote: we should start talking about building a *high performance* flat file loading solution with good column type inference and

[Numpy-discussion] subclassing ndarray

2011-11-21 Thread Chris.Barker
Hi folks, I'm working on a ragged array class -- an array that can store and work with what can be considered tabular data, with the rows of different lengths: ragged_array A ragged array class -- build on numpy The idea is to be able to store data that is essentially 2-d, but each row

Re: [Numpy-discussion] Rebinning numpy array

2011-11-14 Thread Chris.Barker
On 11/13/11 9:55 AM, Olivier Delalleau wrote: idea, since it will throw out a lot of information if you decrease the number of bins: I agree -- I'd think about looking at a smooth interpolation -- maybe kernel density estimation? On 11/14/11 8:12 AM, Sturla Molden wrote: Fit a poisson

Re: [Numpy-discussion] how to use the name of a ndarray as a string

2011-11-14 Thread Chris.Barker
On 11/10/11 3:57 AM, Olivier Delalleau wrote: In such a situation you should probably use a dictionary from the start, all good suggestions, but while we're at it: On 11/10/11 2:17 AM, Chao YUE wrote: Does anyone know how I can quickly use the name of a ndarray as a string? This reflects a

Re: [Numpy-discussion] Cross-Compiling Numpy for NAO

2011-11-08 Thread Chris.Barker
On 11/7/11 10:16 AM, Carlos Neves wrote: I am a robotics student and I have used numpy to develop a controller for a humanoid robot. Now I am trying to implement the same controller to a different robot, NAO - http://www.aldebaran-robotics.com/ This robot has a Linux based OS with Python

Re: [Numpy-discussion] in the NA discussion, what can we agree on?

2011-11-03 Thread Chris.Barker
On 11/2/11 7:16 PM, Nathaniel Smith wrote: By R compatibility, I specifically had in mind in-memory compatibility. The R crowd has had a big voice in this discussion, and I understand that there are some nice lessons to be learned from it with regard to the NA issues. However, I think making

Re: [Numpy-discussion] float64 / int comparison different from float / int comparison

2011-11-01 Thread Chris.Barker
On 10/31/11 6:38 PM, Stéfan van der Walt wrote: On Mon, Oct 31, 2011 at 6:25 PM, Matthew Brettmatthew.br...@gmail.com wrote: Oh, dear, I'm suffering now: In [12]: res 2**31-1 Out[12]: array([False], dtype=bool) I'm seeing: ... Your result seems very strange, because the numpy scalars

Re: [Numpy-discussion] NA masks in the next numpy release?

2011-10-28 Thread Chris.Barker
On 10/27/11 7:51 PM, Travis Oliphant wrote: As I mentioned. I find the ability to separate an ABSENT idea from an IGNORED idea convincing. In other words, I think distinguishing between masks and bit-patterns is not just an implementation detail, but provides a useful concept for multiple

Re: [Numpy-discussion] NA masks in the next numpy release?

2011-10-28 Thread Chris.Barker
On 10/28/11 11:37 AM, Matthew Brett wrote: The main motivation for the alterNEP was our strong feeling that separating ABSENT and IGNORE was easier to comprehend and cleaner. I don't know about easier to comprehend, or cleaner, but it is more feature-full. I see two issues here: 1) being

Re: [Numpy-discussion] yet another indexing question

2011-10-17 Thread Chris.Barker
On 10/14/11 5:04 AM, Neal Becker wrote: suppose I have: In [10]: u Out[10]: array([[0, 1, 2, 3, 4], [5, 6, 7, 8, 9]]) And I have a vector v: v = np.array ((0,1,0,1,0)) I want to form an output vector which selects items from u where v is the index of the row of u to be

Re: [Numpy-discussion] NumPy foundations

2011-10-13 Thread Chris.Barker
On 10/13/11 6:03 AM, Linus Jundén wrote: I am about to make a NumPy presentation for my colleges in about a week. I want to tell them something about the history of the library and what kind of code it relies on. Is NumPy based on some external code like e.g. BLAS, LAPACK etc or is it coded

Re: [Numpy-discussion] array.tofile() refuses to write into a StringIO

2011-09-27 Thread Chris.Barker
On 9/27/11 2:14 AM, oc-spam66 wrote: if you want to write to a string, why not use .tostring()? Because A.tostring() returns the binary data, while I would like the text representation. More precisely, I would like to use A.tofile(sep=\t). I see -- I've always thought mingling binary and

Re: [Numpy-discussion] load from text files Pull Request Review

2011-09-13 Thread Chris.Barker
On 9/12/11 4:38 PM, Christopher Jordan-Squire wrote: I did some timings to see what the advantage would be, in the simplest case possible, of taking multiple lines from the file to process at a time. Nice work, only a minor comment: f6 and f7 use stripped down versions of Chris Barker's

Re: [Numpy-discussion] load from text files Pull Request Review

2011-09-08 Thread Chris.Barker
On 9/8/11 1:43 PM, Christopher Jordan-Squire wrote: I just ran a quick test on my machine of this idea. With dt = np.dtype([('x',np.float32),('y', np.int32),('z', np.float64)]) temp = np.empty((), dtype=dt) temp2 = np.zeros(1,dtype=dt) In [96]: def f(): ...: l=[0]*3 ...:

Re: [Numpy-discussion] load from text files Pull Request Review

2011-09-07 Thread Chris.Barker
On 9/2/11 2:45 PM, Christopher Jordan-Squire wrote: It doesn't have to parse the entire file to determine the dtypes. It builds up a regular expression for what it expects to see, in terms of dtypes. Then it just loops over the lines, only parsing if the regular expression doesn't match. It

Re: [Numpy-discussion] load from text files Pull Request Review

2011-09-02 Thread Chris.Barker
On 9/2/11 8:22 AM, Derek Homeier wrote: I agree it would make a very nice addition, and could complement my pre-allocation option for loadtxt - however there I've also been made aware that this approach breaks streamed input etc., so the buffer.resize(…) methods in accumulator would be the

Re: [Numpy-discussion] load from text files Pull Request Review

2011-09-02 Thread Chris.Barker
On 9/2/11 9:16 AM, Christopher Jordan-Squire wrote: I agree it would make a very nice addition, and could complement my pre-allocation option for loadtxt - however there I've also been made aware that this approach breaks streamed input etc., so the buffer.resize(…) methods in accumulator

Re: [Numpy-discussion] Numpy performance boost

2011-08-31 Thread Chris.Barker
On 8/31/11 3:58 AM, Dieter Weber wrote: just wanted to show an example of how python3 + numpy compares with just python3 and many other languages and language implementations: http://shootout.alioth.debian.org/u64q/performance.php?test=mandelbrot#about hmmm - it would be interesting to see

Re: [Numpy-discussion] load from text files Pull Request Review

2011-08-30 Thread Chris.Barker
On 8/27/11 11:08 AM, Christopher Jordan-Squire wrote: I've submitted a pull request for a new method for loading data from text files into a record array/masked record array. Click on the link for more info, but the general idea is to create a regular expression for what entries should look

Re: [Numpy-discussion] saving groups of numpy arrays to disk

2011-08-26 Thread Chris.Barker
On 8/26/11 5:04 AM, Derek Homeier wrote: Hmm, the pure Python version might be, but, I've used cPickle for a long time and never noted any stability problems. well, here is the NEP: https://github.com/numpy/numpy/blob/master/doc/neps/npy-format.txt It addresses the why's and hows of the

Re: [Numpy-discussion] saving groups of numpy arrays to disk

2011-08-25 Thread Chris.Barker
On 8/24/11 9:22 AM, Anthony Scopatz wrote: You can use Python pickling, if you do *not* have a requirement for: I can't recall why, but it seem pickling of numpy arrays has been fragile and not very performant. I like the npy / npz format, built in to numpy, if you don't need: -

Re: [Numpy-discussion] numpy array serialization with JSON

2008-11-11 Thread Chris.Barker
Simon Palmer wrote: Does JSON have a representation for n-d arrays? In my little work with it, it looked pretty lame for arrays of number, so I'd be surprised. yes it does, thet are just treated as nested lists and the square bracket notation is used. then it looks like one of str(array)

Re: [Numpy-discussion] Using 2-D arrays in Numeric Python (numpy)

2008-10-13 Thread Chris.Barker
Bill Baxter wrote: import numpy as npy Bill, for what it's worth, I *think* this group has reached a consensus to use: import numpy as np We all have different tastes for how they might want to spell it, but the more consistent we are, the easier it will be for newbies. -Chris --

Re: [Numpy-discussion] Using 2-D arrays in Numeric Python (numpy)

2008-10-13 Thread Chris.Barker
Linda Seltzer wrote: I would appreciate it if someone could answer my question without referring to subjects such as APIs and interfaces, since I am only concerned with a mathematical application at this time. caution: this is a bit rude -- that was an excellent and informative answer to your

Re: [Numpy-discussion] Binary ufuncs: minimum

2008-05-28 Thread Chris.Barker
Keith Goodman wrote: Interestingly, MATLAB (v7.5.0) takes a different approach: ans = 1271 -A ans = 127 -1 can anyone explain that? -- just curious. Charles R Harris wrote: We could simply define the range of int8 as [-127,127], but that is somewhat problematical also. That

Re: [Numpy-discussion] Uncomfortable with matrix change

2008-05-12 Thread Chris.Barker
Could we add a from __future__ import something along with a deprecation warning? This could be used for Tim's new matrix class, or any other API change. -Chris -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/ORR(206) 526-6959 voice 7600 Sand

[Numpy-discussion] Broadcasting question

2008-05-01 Thread Chris.Barker
Hi all, I have a n X m X 3 array, and I a n X M array. I want to assign the values in the n X m to all three of the slices in the bigger array: A1 = np.zeros((5,4,3)) A2 = np.ones((5,4)) A1[:,:,0] = A2 A1[:,:,1] = A2 A1[:,:,2] = A2 However,it seems I should be able to broadcast that, so I

Re: [Numpy-discussion] recarray fun

2008-04-30 Thread Chris.Barker
Travis E. Oliphant wrote: Stéfan van der Walt wrote: 2008/4/30 Christopher Barker [EMAIL PROTECTED]: Since it is optional, shouldn't it be keyword argument? Thanks, fixed in r5115. This was too hasty. I had considered this before. The problem with this is that the object can