[Numpy-discussion] Numpy savetxt: change decimal separator

2009-09-24 Thread markus . proeller
Hello everyone, I save data to a file with the following statement: np.savetxt(fileName, transpose((average_dist, std_deviation, maximum_dist, sum_of_dist)), delimiter = ';', fmt='%6.10f') is there a possibility to change the decimal seperator from a point to comma ? And another question I

[Numpy-discussion] Numpy extension writing problems

2009-09-24 Thread Jeremy Sanders
Hi - I've never written a Python extension before, so I apologise in advance for my lack of knowledge. I'm trying to interpret a variable length tuple of variable length numpy arrays, convert then to C double arrays and pass them to a C++ function. I'm using SIP (as I also need to deal with

Re: [Numpy-discussion] Numpy savetxt: change decimal separator

2009-09-24 Thread Gökhan Sever
On Thu, Sep 24, 2009 at 2:07 AM, markus.proel...@ifm.com wrote: Hello everyone, I save data to a file with the following statement: np.savetxt(fileName, transpose((average_dist, std_deviation, maximum_dist, sum_of_dist)), delimiter = ';', fmt='%6.10f') is there a possibility to change

[Numpy-discussion] Resize Method for Numpy Array

2009-09-24 Thread Alice Invernizzi
Dear all, I have an Hamletic doubt concerning the numpy array data type. A general learned rule concerning the array usage in other high-level programming languages is that array data-type are homogeneous datasets of fixed dimension. Therefore, is not clear to me why in numpy the size of an

Re: [Numpy-discussion] Resize Method for Numpy Array

2009-09-24 Thread V. Armando Solé
Alice Invernizzi wrote: Dear all, I have an Hamletic doubt concerning the numpy array data type. A general learned rule concerning the array usage in other high-level programming languages is that array data-type are homogeneous datasets of fixed dimension. Therefore, is not clear to

Re: [Numpy-discussion] Resize Method for Numpy Array

2009-09-24 Thread V. Armando Solé
V. Armando Solé wrote: Sorry, there was a bug in the sent code. It should be: import numpy a=numpy.arange(100.) a.shape = 10, 10 b = a * 1 # just to get a copy b.shape = 5, 2, 5, 2 b = (b.sum(axis=3)).sum(axis=1) In that way, on b I have a binned image of a.

Re: [Numpy-discussion] Numpy savetxt: change decimal separator

2009-09-24 Thread Junda Zhu
On Sep 24, 2009, at 3:07 AM, markus.proel...@ifm.com wrote: Hello everyone, I save data to a file with the following statement: np.savetxt(fileName, transpose((average_dist, std_deviation, maximum_dist, sum_of_dist)), delimiter = ';', fmt='%6.10f') is there a possibility to change the

Re: [Numpy-discussion] Coercing object arrays to string (or unicode) arrays

2009-09-24 Thread Christopher Barker
Michael Droettboom wrote: As I'm looking into fixing a number of bugs in chararray, I'm running into some surprising behavior. In [14]: x = np.array(['abcdefgh', 'ijklmnop'], 'O') # Without specifying the length, it seems to default to sizeof(int)... ??? In [15]: np.array(x, 'S') Out[15]:

Re: [Numpy-discussion] Coercing object arrays to string (or unicode) arrays

2009-09-24 Thread Michael Droettboom
On 09/24/2009 01:02 PM, Christopher Barker wrote: Michael Droettboom wrote: As I'm looking into fixing a number of bugs in chararray, I'm running into some surprising behavior. In [14]: x = np.array(['abcdefgh', 'ijklmnop'], 'O') # Without specifying the length, it seems to default to

Re: [Numpy-discussion] Resize Method for Numpy Array

2009-09-24 Thread Christopher Barker
Alice Invernizzi wrote: Therefore, is not clear to me why in numpy the size of an array can be changed (either with the 'returning-value' resize() function either with the 'in-place' array method resize()). Would you please be so kind to give some explanation for the existence of resize

[Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Charles R Harris
Hi All, Would it be appropriate to add a class similar to poly but instead using chebyshev polynomials? That is, where we currently have 'poly', 'poly1d', 'polyadd', 'polyder', 'polydiv', 'polyfit', 'polyint', 'polymul', 'polysub', 'polyval', change poly to cheb. The rational here is

Re: [Numpy-discussion] Coercing object arrays to string (or unicode) arrays

2009-09-24 Thread Michael Droettboom
I have filed a bug against this, along with a patch that fixes casting to fixed-size string arrays: http://projects.scipy.org/numpy/ticket/1235 Undefined-sized string arrays is a harder problem, which I'm deferring for later. Mike On 09/24/2009 01:19 PM, Michael Droettboom wrote: On

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Pauli Virtanen
to, 2009-09-24 kello 11:51 -0600, Charles R Harris kirjoitti: Would it be appropriate to add a class similar to poly but instead using chebyshev polynomials? That is, where we currently have [clip] Yes, I think. scipy.special.orthogonal would be the best place for this, I think. Numpy would

Re: [Numpy-discussion] Resize Method for Numpy Array

2009-09-24 Thread Robert Kern
On Thu, Sep 24, 2009 at 09:58, Alice Invernizzi inverni...@cilea.it wrote: Dear all, I have an Hamletic doubt concerning the numpy array data type. A general learned rule concerning the array usage in other high-level programming languages is that array data-type are homogeneous datasets of 

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Robert Kern
On Thu, Sep 24, 2009 at 14:18, Pauli Virtanen p...@iki.fi wrote: As a side note, should the cheby* versions of `polyval`, `polymul` etc. just be dropped to reduce namespace clutter? You can do the same things already within just class methods and arithmetic. Just to clarify, you mean having

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Pauli Virtanen
to, 2009-09-24 kello 14:31 -0500, Robert Kern kirjoitti: On Thu, Sep 24, 2009 at 14:18, Pauli Virtanen p...@iki.fi wrote: As a side note, should the cheby* versions of `polyval`, `polymul` etc. just be dropped to reduce namespace clutter? You can do the same things already within just class

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Charles R Harris
On Thu, Sep 24, 2009 at 1:18 PM, Pauli Virtanen p...@iki.fi wrote: to, 2009-09-24 kello 11:51 -0600, Charles R Harris kirjoitti: Would it be appropriate to add a class similar to poly but instead using chebyshev polynomials? That is, where we currently have [clip] Yes, I think.

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Charles R Harris
On Thu, Sep 24, 2009 at 1:31 PM, Robert Kern robert.k...@gmail.com wrote: On Thu, Sep 24, 2009 at 14:18, Pauli Virtanen p...@iki.fi wrote: As a side note, should the cheby* versions of `polyval`, `polymul` etc. just be dropped to reduce namespace clutter? You can do the same things

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Pauli Virtanen
to, 2009-09-24 kello 13:53 -0600, Charles R Harris kirjoitti: [clip] I was thinking of storing the chebyshev internally as the values at the chebyschev points. This makes multiplication, differentiation and such quite easy (resample and multiply/divide appropriatately). Its equivalent to

Re: [Numpy-discussion] Numpy savetxt: change decimal separator

2009-09-24 Thread Tim Michelsen
And another question I import this file to excel, is there also a possiblity to create a headline for each column, that the file looks like the following example: average; standard deviation; maximum distance; sum of distances 0,26565; 0,65565; 2,353535; 25, 5656 I was fiddeling with

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Charles R Harris
On Thu, Sep 24, 2009 at 2:34 PM, Pauli Virtanen p...@iki.fi wrote: to, 2009-09-24 kello 13:53 -0600, Charles R Harris kirjoitti: [clip] I was thinking of storing the chebyshev internally as the values at the chebyschev points. This makes multiplication, differentiation and such quite

[Numpy-discussion] np.any and np.all short-circuiting

2009-09-24 Thread Citi, Luca
Hello I noticed that python's any can be faster than numpy's any (and the similarly for all). Then I wondered why. I realized that numpy implements any as logical_or.reduce (and all as logical_and.reduce). This means that numpy cannot take advantage of short-circuiting. Looking at the timings

Re: [Numpy-discussion] np.any and np.all short-circuiting

2009-09-24 Thread Charles R Harris
On Thu, Sep 24, 2009 at 3:43 PM, Citi, Luca lc...@essex.ac.uk wrote: Hello I noticed that python's any can be faster than numpy's any (and the similarly for all). Then I wondered why. I realized that numpy implements any as logical_or.reduce (and all as logical_and.reduce). This means that

Re: [Numpy-discussion] np.any and np.all short-circuiting

2009-09-24 Thread Robert Kern
On Thu, Sep 24, 2009 at 16:43, Citi, Luca lc...@essex.ac.uk wrote: What is the correct way of running the tests (without installing the development version in the system)? Build inplace: $ python setup.py build_src --inplace build_ext --inplace -- Robert Kern I have come to believe that

Re: [Numpy-discussion] np.any and np.all short-circuiting

2009-09-24 Thread Citi, Luca
Thank you for your instantaneuos reply! This is what I usually do: from the numpy folder I run (emptying the build folder if I just fetched svn updates) $ python setup build.py $ cd build/lib-... $ ipython In [1]: import numpy as np In [2]: np.__version__ Out[2]: '1.4.0.dev7417' Everything

Re: [Numpy-discussion] np.any and np.all short-circuiting

2009-09-24 Thread Citi, Luca
Thank you both for your help! $ python setup.py build_src --inplace build_ext --inplace I'll give it a try. ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion

Re: [Numpy-discussion] Resize Method for Numpy Array

2009-09-24 Thread Sturla Molden
Robert Kern skrev: While this description is basically true of numpy arrays, I would caution you that every language has a different lexicon, and the same word can mean very different things in each. For example, Python lists are *not* linked lists; they are like C++'s std::vectors with a

Re: [Numpy-discussion] Resize Method for Numpy Array

2009-09-24 Thread Robert Kern
On Thu, Sep 24, 2009 at 17:32, Sturla Molden stu...@molden.no wrote: Robert Kern skrev: While this description is basically true of numpy arrays, I would caution you that every language has a different lexicon, and the same word can mean very different things in each. For example, Python lists

Re: [Numpy-discussion] Resize Method for Numpy Array

2009-09-24 Thread Sturla Molden
Robert Kern skrev: collections.deque() is a linked list of 64-item chunks. Thanks for that useful information. :-) But it would not help much for a binary tree... Since we are on the NumPy list... One could image making linked lists using NumPy arrays with dtype=object. They are storage

Re: [Numpy-discussion] dtype '|S0' not understood

2009-09-24 Thread David Warde-Farley
On 23-Sep-09, at 7:55 PM, David Warde-Farley wrote: It seems that either dtype(str) should do something more sensible than zero-length string, or it should be possible to create it with dtype('| S0'). Which should it be? Since there wasn't any response I went ahead and fixed it by making

Re: [Numpy-discussion] np.any and np.all short-circuiting

2009-09-24 Thread Citi, Luca
I am sorry. I followed your suggestion. I re-checked out the svn folder and then compiled with $ python setup.py build_src --inplace build_ext --inplace but I get the same behaviour. If I am inside I get the NameError, if I am outside and use path.insert, it successfully performs zero tests. I

[Numpy-discussion] Assigning an array to the field of a structure doesn't work

2009-09-24 Thread Jeremy Lewi
Hi I'm trying to understand the following code: import numpy as np dt=np.dtype([(c,np.int32,(2))]) data=np.ndarray([2],dtype=dt) x=np.array([0,10]) #the following line doesn't set data[0][c] = x #only data[0][c][0] changes

Re: [Numpy-discussion] np.any and np.all short-circuiting

2009-09-24 Thread David Cournapeau
On Fri, Sep 25, 2009 at 9:50 AM, Citi, Luca lc...@essex.ac.uk wrote: I am sorry. I followed your suggestion. I re-checked out the svn folder and then compiled with $ python setup.py build_src --inplace build_ext --inplace but I get the same behaviour. If I am inside I get the NameError, if I

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Charles R Harris
On Thu, Sep 24, 2009 at 1:31 PM, Robert Kern robert.k...@gmail.com wrote: On Thu, Sep 24, 2009 at 14:18, Pauli Virtanen p...@iki.fi wrote: As a side note, should the cheby* versions of `polyval`, `polymul` etc. just be dropped to reduce namespace clutter? You can do the same things

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Robert Kern
On Thu, Sep 24, 2009 at 21:00, Charles R Harris charlesr.har...@gmail.com wrote: On Thu, Sep 24, 2009 at 1:31 PM, Robert Kern robert.k...@gmail.com wrote: On Thu, Sep 24, 2009 at 14:18, Pauli Virtanen p...@iki.fi wrote: As a side note, should the cheby* versions of `polyval`, `polymul`

Re: [Numpy-discussion] chebyshev polynomials

2009-09-24 Thread Charles R Harris
On Thu, Sep 24, 2009 at 8:14 PM, Robert Kern robert.k...@gmail.com wrote: On Thu, Sep 24, 2009 at 21:00, Charles R Harris charlesr.har...@gmail.com wrote: On Thu, Sep 24, 2009 at 1:31 PM, Robert Kern robert.k...@gmail.com wrote: On Thu, Sep 24, 2009 at 14:18, Pauli Virtanen

[Numpy-discussion] Antwort: Re: Numpy savetxt: change decimal separator

2009-09-24 Thread markus . proeller
I was fiddeling with the same problem here: http://thread.gmane.org/gmane.comp.python.numeric.general/23418 So far, one can only open the file and prepend the header line. I just files an enhancement request for this: proposal: add a header and footer function to numpy.savetxt