Re: [Numpy-discussion] Another reality check

2010-07-12 Thread Jochen Schröder
On 07/12/2010 12:36 PM, David Goldsmith wrote: On Sun, Jul 11, 2010 at 6:18 PM, David Goldsmith d.l.goldsm...@gmail.com mailto:d.l.goldsm...@gmail.com wrote: In numpy.fft we find the following: Then A[1:n/2] contains the positive-frequency terms, and A[n/2+1:] contains the

[Numpy-discussion] Function returns nothing!

2010-07-12 Thread allan oware
Hi All! def height_diffs(): h = [] i = 0 while True: x = raw_input(Enter height difference ) if x == 'q': break else: h.append(x) i = i + 1 m = asarray(h,dtype=float) return m why does return statement return

Re: [Numpy-discussion] BOF notes: Fernando's proposal: NumPy?ndarray with named axes

2010-07-12 Thread Gael Varoquaux
On Sun, Jul 11, 2010 at 11:59:30AM +, Neil Crighton wrote: What is a use case for the new array type that can't be solved by structured/record arrays? Sounds like it was decided at the Sciy BOF they were a good idea, several people have implemented a version of them and Fernando and Gael

Re: [Numpy-discussion] Function returns nothing!

2010-07-12 Thread Scott Sinclair
On 12 July 2010 11:45, allan oware lumte...@gmail.com wrote: Hi All! def height_diffs():     h = []     i = 0     while True:     x = raw_input(Enter height difference )     if x == 'q':     break     else:     h.append(x)     i = i + 1     m =

Re: [Numpy-discussion] BOF notes: Fernando's proposal : NumPy?ndarray with named axes

2010-07-12 Thread Neil Crighton
Gael Varoquaux gael.varoquaux at normalesup.org writes: Let say that you have a dataset that is in a 3D array, where axis 0 corresponds to days, axis 1 to hours of the day, and axis 2 to temperature, you might want to have the mean of the temperature in each day, which would be in current

Re: [Numpy-discussion] Another reality check

2010-07-12 Thread Fabrice Silva
Le lundi 12 juillet 2010 à 18:14 +1000, Jochen Schröder a écrit : On 07/12/2010 12:36 PM, David Goldsmith wrote: On Sun, Jul 11, 2010 at 6:18 PM, David Goldsmith d.l.goldsm...@gmail.com mailto:d.l.goldsm...@gmail.com wrote: In numpy.fft we find the following: Then A[1:n/2]

Re: [Numpy-discussion] BOF notes: Fernando's proposal: NumPy?ndarray with named axes

2010-07-12 Thread Ryan May
On Mon, Jul 12, 2010 at 8:04 AM, Neil Crighton neilcrigh...@gmail.com wrote: Gael Varoquaux gael.varoquaux at normalesup.org writes: I do such manipulation all the time, and keeping track of which axis is what is fairly tedious and error prone. It would be much nicer to be able to write:    

Re: [Numpy-discussion] BOF notes: Fernando's?proposal:?NumPy?ndarray with named axes

2010-07-12 Thread Gael Varoquaux
On Mon, Jul 12, 2010 at 01:04:55PM +, Neil Crighton wrote: Thanks, that's a really nice description. Instead of data.ax_day.mean(axis=0) I think it would be clearer to do something like data.mean(axis='day') Yes, that's even better. The problem is that it does not extend to operations

Re: [Numpy-discussion] Another reality check

2010-07-12 Thread David Goldsmith
Thanks, both. On Mon, Jul 12, 2010 at 5:39 AM, Fabrice Silva si...@lma.cnrs-mrs.frwrote: Le lundi 12 juillet 2010 à 18:14 +1000, Jochen Schröder a écrit : On 07/12/2010 12:36 PM, David Goldsmith wrote: On Sun, Jul 11, 2010 at 6:18 PM, David Goldsmith d.l.goldsm...@gmail.com

[Numpy-discussion] Memory leak found in ndarray (I think)?

2010-07-12 Thread Wes McKinney
This one was quite a bear to track down, starting from the of course very high level observation of why is my application leaking memory. I've reproduced it on Windows XP using NumPy 1.3.0 on Python 2.5 and 1.4.1 on Python 2.6 (EPD). Basically it seems that calling .astype(bool) on an ndarray

[Numpy-discussion] 3 dim array unpacking

2010-07-12 Thread K . -Michael Aye
Dear numpy hackers, I can't find the syntax for unpacking the 3 dimensions of a rgb array. so i have a MxNx3 image array 'img' and would like to do: red, green, blue = img[magical_slicing] Which slicing magic do I need to apply? Thanks for your help! BR, Michael

Re: [Numpy-discussion] 3 dim array unpacking

2010-07-12 Thread Anne Archibald
On 12 July 2010 13:24, K.-Michael Aye kmichael@gmail.com wrote: Dear numpy hackers, I can't find the syntax for unpacking the 3 dimensions of a rgb array. so i have a MxNx3 image array 'img' and would like to do: red, green, blue = img[magical_slicing] Which slicing magic do I need to

Re: [Numpy-discussion] Memory leak found in ndarray (I think)?

2010-07-12 Thread Wes McKinney
On Mon, Jul 12, 2010 at 2:22 PM, Wes McKinney wesmck...@gmail.com wrote: This one was quite a bear to track down, starting from the of course very high level observation of why is my application leaking memory. I've reproduced it on Windows XP using NumPy 1.3.0 on Python 2.5 and 1.4.1 on

Re: [Numpy-discussion] Memory leak found in ndarray (I think)?

2010-07-12 Thread Nathaniel Peterson
This memory leak may be related: http://projects.scipy.org/numpy/ticket/1542 It shows what appears to be a memory leak when calling astype('float') on an array of dtype 'object'. ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org

Re: [Numpy-discussion] Memory leak found in ndarray (I think)?

2010-07-12 Thread Wes McKinney
On Mon, Jul 12, 2010 at 3:39 PM, Nathaniel Peterson nathanielpeterso...@gmail.com wrote: This memory leak may be related: http://projects.scipy.org/numpy/ticket/1542 It shows what appears to be a memory leak when calling astype('float') on an array of dtype 'object'.

[Numpy-discussion] numpy.fft, yet again

2010-07-12 Thread David Goldsmith
From the docstring: A[0] contains the zero-frequency term (the mean of the signal) And yet, consistent w/ the definition given in the docstring (and included w/ an earlier email), the code gives, e.g.: import numpy as np x = np.ones((16,)); x array([ 1., 1., 1., 1., 1., 1., 1., 1.,

Re: [Numpy-discussion] BOF notes: Fernando's proposal: NumPy ndarray with named axes

2010-07-12 Thread Neil Crighton
Rob Speer rspeer at MIT.EDU writes: It's not just about the rows: a 2-D datarray can also index by columns, an operation that has no equivalent in a 1-D array of records like your example. rec['305'] effectively indexes by column. This is one the main attractions of structured/record arrays.

Re: [Numpy-discussion] numpy.fft, yet again

2010-07-12 Thread Eric Firing
On 07/12/2010 11:43 AM, David Goldsmith wrote: From the docstring: A[0] contains the zero-frequency term (the mean of the signal) And yet, consistent w/ the definition given in the docstring (and included w/ an earlier email), the code gives, e.g.: import numpy as np x =

Re: [Numpy-discussion] numpy.fft, yet again

2010-07-12 Thread David Goldsmith
On Mon, Jul 12, 2010 at 3:04 PM, Eric Firing efir...@hawaii.edu wrote: On 07/12/2010 11:43 AM, David Goldsmith wrote: From the docstring: A[0] contains the zero-frequency term (the mean of the signal) And yet, consistent w/ the definition given in the docstring (and included w/ an

Re: [Numpy-discussion] BOF notes: Fernando's proposal: NumPy ndarray with named axes

2010-07-12 Thread Rob Speer
rec['305'] extracts a single value from a single record. arr.named[:,305] extracts an *entire column* from a 2-D datarray, returning you a 1-D datarray. Once again, 1-D record arrays and 2-D labeled arrays look similar when you print them, but the data structures are so unrelated that there is

Re: [Numpy-discussion] Memory leak found in ndarray (I think)?

2010-07-12 Thread Nathaniel Peterson
Wes McKinney wesmck...@gmail.com writes: Did you mean to post a different link? That's the ticket I just created :) How silly of me! I meant http://projects.scipy.org/numpy/ticket/1427 ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org

[Numpy-discussion] Here's what I've done to numpy.fft

2010-07-12 Thread David Goldsmith
In light of my various questions and the responses thereto, here's what I've done (but not yet committed) to numpy.fft. There are many ways to define the DFT, varying in the sign of the exponent, normalization, etc. In this implementation, the DFT is defined as .. math:: A_k =

Re: [Numpy-discussion] BOF notes: Fernando's proposal: NumPy ndarray with named axes

2010-07-12 Thread Robert Kern
On Mon, Jul 12, 2010 at 17:30, Rob Speer rsp...@mit.edu wrote: rec['305'] extracts a single value from a single record. No, in Neil's example `rec` was a structured array. You can index structured arrays using the names of the record members, not just scalars. arr.named[:,305] extracts an

Re: [Numpy-discussion] Here's what I've done to numpy.fft

2010-07-12 Thread Travis Oliphant
On Jul 12, 2010, at 5:47 PM, David Goldsmith wrote: In light of my various questions and the responses thereto, here's what I've done (but not yet committed) to numpy.fft. There are many ways to define the DFT, varying in the sign of the exponent, normalization, etc. In this

Re: [Numpy-discussion] numpy.fft, yet again

2010-07-12 Thread Jochen Schröder
On 13/07/10 08:04, Eric Firing wrote: On 07/12/2010 11:43 AM, David Goldsmith wrote: From the docstring: A[0] contains the zero-frequency term (the mean of the signal) And yet, consistent w/ the definition given in the docstring (and included w/ an earlier email), the code gives, e.g.:

Re: [Numpy-discussion] Here's what I've done to numpy.fft

2010-07-12 Thread David Goldsmith
On Mon, Jul 12, 2010 at 6:33 PM, Travis Oliphant oliph...@enthought.comwrote: On Jul 12, 2010, at 5:47 PM, David Goldsmith wrote: In light of my various questions and the responses thereto, here's what I've done (but not yet committed) to numpy.fft. There are many ways to define the

Re: [Numpy-discussion] Here's what I've done to numpy.fft

2010-07-12 Thread Jochen Schröder
On 13/07/10 08:47, David Goldsmith wrote: In light of my various questions and the responses thereto, here's what I've done (but not yet committed) to numpy.fft. There are many ways to define the DFT, varying in the sign of the exponent, normalization, etc. In this implementation, the DFT is

[Numpy-discussion] match or vectorized in-type function.

2010-07-12 Thread James Bullard
I have two vectors of integers of not necessarily the same length. Consider the hypothetical function match (or if you are familiar to R then consider that function). match(v1, v2) = returns a boolean array of length len(v1) indicating whether element i in v1 is in v2. I cannot find this

Re: [Numpy-discussion] match or vectorized in-type function.

2010-07-12 Thread Zachary Pincus
match(v1, v2) = returns a boolean array of length len(v1) indicating whether element i in v1 is in v2. You want numpy.in1d (and friends, probably, like numpy.unique and the others that are all collected in numpy.lib.arraysetops...) Definition: numpy.in1d(ar1, ar2, assume_unique=False)

Re: [Numpy-discussion] numpy.fft, yet again

2010-07-12 Thread David Goldsmith
2010/7/12 Jochen Schröder cycoma...@gmail.com On 13/07/10 08:04, Eric Firing wrote: On 07/12/2010 11:43 AM, David Goldsmith wrote: From the docstring: A[0] contains the zero-frequency term (the mean of the signal) And yet, consistent w/ the definition given in the docstring (and

Re: [Numpy-discussion] Here's what I've done to numpy.fft

2010-07-12 Thread David Goldsmith
2010/7/12 Jochen Schröder cycoma...@gmail.com On 13/07/10 08:47, David Goldsmith wrote: In light of my various questions and the responses thereto, here's what I've done (but not yet committed) to numpy.fft. There are many ways to define the DFT, varying in the sign of the exponent,

[Numpy-discussion] Re FFTs in SciPy (and NumPy)

2010-07-12 Thread Sturla Molden
There has been some discussion on FFTPACK lately. Problems with FFTPACK seems to be: - Written in old Fortran 77. - Unprecise for single precision. - Can sometimes be very slow, depending on input size. - Can only handle a few small prime factors {2,3,4,5} efficiently. - How to control integer