Mailman 3 December 2000 - NumPy-Discussion

simple array help?
by Pete Shinners Sept. 17, 2001

Sept. 17, 2001

i have a simple array with floating values >>> print a array([ 0. , 0.2, 0.4, 0.6, 0.8]) what i need to do is change each index into another dimension with 3 indices. hmm, kind of confusing, an example will explain better >>> b = array(zip(a,a,a)) >>> print b array([[ 0. , 0. , 0. ], [ 0.2, 0.2, 0.2], [ 0.4, 0.4, 0.4], [ 0.6, 0.6, 0.6], [ 0.8, 0.8, 0.8]]) ok, this does the job, but once i start using large arrays, the back-n-forth conversion between arrays and python lists is costing me quite a bit. is there a way i can reshape the array this way without the call to python's 'zip'? (no, 'map' doesn't count either) i've tried much fooling with NewAxis, resize, and friends. but either i haven't stumbled upon the correct combination or i'm not trying the correct tools. i'd like to keep this as quick as possible, so hopefully it can be done without anything too elaborate. thanks (doh, sorry for the previous distutils related post... hit the wrong mailing list)

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Numpy install problems
by Michael D. Risser July 27, 2001

July 27, 2001

When attempting to install Numeric 17.0 with Python 1.5.2 and Distutils 1.0 on Red Hat 7.0, I get the following error after issuing the command 'python setup.py install' Traceback (innermost last): File "setup.py", line 15, in ? vs = map(string.atoi, v.groups()) AttributeError: 'None' object has no attribute 'groups' This error occurs regardless of whether or not I am root. I have also tried uninstalling the Red Hat Python packages and installing all from source, but I get the same error. Any help would be appreciated. Thanks.

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[Q]Best way for an array operation?
by Daehyok Shin May 4, 2001

May 4, 2001

What is the best Numpy way for the following work? for i in range(len(x)): if x[i] > 0: y[i] = v[i] z[i] = u[i]+2 Daehyok Shin (Peter)

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Numpy doesn't build properly
by Tony Seward Jan. 3, 2001

Jan. 3, 2001

Because the Numpy sub-packages use '#include "Numeric/arratobject.h", the Numeric package will not build from scratch. This may not matter if one does a 'python setup_all.py install' as long as the base Numeric package is installed before the sub-packages are built. I don't think that this is what setup_all.py does because the core setup.py is called with no arguments. In any case, I'm trying to build RPMs and the build and install processes are seperated. In order to build the packages seprately I am now putting a symbolic link in each package's Include directory called Numeric that points to the Include directory for the core package. I would like to suggest that the core header files be put in a directory 'Include/Numeric' rather than directly in 'Include'. That way the header file locations more acurately mirror the way that they are installed. Tony

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Re: [Numpy-discussion] Da Blas
by Frank Horowitz Jan. 2, 2001

Jan. 2, 2001

At 3:14 PM -0700 14/9/00, <dubois(a)users.sourceforge.net> wrote: >Well, I certainly didn't mean to flame anyone in particular, so I'm sorry >that Frank was offended. Publicly apologized, and publicly accepted. I'm sorry I lost my cool. Ray Beausoleil and I are having a look at this too. He's coming at the problem from a Windows perspective, and I'm coming at it from a Linux/Unix perspective. It's going to be a little slow going for me at first, since it appears that I'm going to have to get my head around the distutils way of doing things.... Just in case it saves anyone else following a false lead, yes, there is a bug in the (Linux Mandrake 7.1; but probably any unix-ish box) compile line for building the lapack_lite.so shared library (i.e. what is generated on my box is "-L/usr/lib-llapack" which obviously is missing a blank before the "-llapack" substring). However, when I coerced the distutils system to get around that bug (by specifying "/usr/lib " with a trailing blank for the BLASLIBDIR and LAPACKLIBDIR variables in setup.py) the same problem (i.e. an "ImportError: /usr/lib/liblapack.so.3: undefined symbol: e_wsfe" in importing lapack_lite) ultimately manifested itself. So my advice is not to bother tracking that one down (although it probably should be reported as a bug in distutils, since adding that trailing blank algorithmically instead of in a user modifiable configuration string is the "right thing to do", TM.). I'm still puzzled by Thomas Breul's report of preloading an f2c library squashing the bug under RedHat 6.2(?). That does not work under Mandrake, although clearly there is some bloody symbol table missing from somewhere. The trouble is to find out where, and then to coerce distutils to deal with that in a portable way... Frank -- -- Frank Horowitz frank(a)ned.dem.csiro.au CSIRO-Exploration & Mining, PO Box 437, Nedlands, WA 6009, AUSTRALIA Direct: +61 8 9284 8431; FAX: +61 8 9389 1906; Reception: +61 8 9389 8421

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Documentation updated
by Paul F. Dubois Dec. 29, 2000

Dec. 29, 2000

Sorry this is in HTML, but the documentation below requires it. The latest source release is 17.2.0. Revised documentation in HTML and PDF is available at http://numpy.sourceforge.net. Package MA contains a number of new constructors. The complete list is: Constructing masked arrays 1.. array (data, typecode = None, copy = 1, savespace = 0, mask = None, fill_value = None) creates a masked array with the given data and mask. The name array is simply an alias for the class name, MA. This constructor sets the data area of the resulting masked array to filled (data, value = fill_value, copy = copy, savespace = savespace), the mask to make_mask (mask, savespace), and the fill value is set to fill_value. The class name MA may also be used instead of the name array. 2.. masked_array (data, mask = None, fill_value = None) is an easier to use version of array, for the common case of typecode = None, copy = 0. When data is newly-created this function can be used to make it a masked array without copying the data if data is already a Numeric array. 3.. masked_values (data, value, rtol=1.e-5, atol=1.e-8, typecode = None, copy = 1, savespace = 0) constructs a masked array whose mask is set at those places where abs (data - value) < atol + rtol * abs (data). That is a careful way of saying that those elements of the data that have value = value (to within a tolerance) are to be treated as invalid. 4.. masked_object (data, value, copy=1, savespace=0) creates a masked array with those entries marked invalid that are equal to value. Again, copy and savespace are passed on to the Numeric array constructor. 5.. masked_where (condition, data) creates a masked array whose shape is that of condition, whose values are those of data, and which is masked where elements of condition are true. 6.. masked_greater (data, value) is equivalent to masked_where (greater(data, value), data)). Similarly, masked_greater_equal, masked_equal, masked_not_equal, masked_less, masked_less_equal are called in the same way with the obvious meanings. Note that for floating point data, masked_values is preferable to masked_equal in most cases. On entry to any of these constructors, data must be any object which the Numeric package can accept to create an array (with the desired typecode, if specified). The mask if given must be None or any object that can be turned into a Numeric array of integer type (it will be converted to typecode MaskType, if necessary), have the same shape as data, and contain only values of 0 or 1. If the mask is not None but its shape does not match that of data, an exception will be thrown, unless one of the two is of length 1, in which case the scalar will be resized (using Numeric.resize) to match the other.

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CXX versions
by pfenn＠mmm.com Dec. 21, 2000

Dec. 21, 2000

Hi, I'm playing around with CXX because I'm going to be writing an extension in the next few days. I'm on WinNT running Microsoft Visual C++ 6.0 with service pack 3 installed. Also, Python 2.0. I've gotten all of CXX-5.0b to compile, and I compiled the demo. This required a slight edit of cxx_extensions.cxx which was documented in the SourceForge buglist for CXX. I was pleasantly surprised that VC++ was able to compile this code. However, when I import CXX.example python crashes. Is this a known problem, is there a workaround, or should I try CXX-4.2 instead? For some reason, I am really adverse to writing another extension using C. Tom Fenn

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17.2.0
by Paul F. Dubois Dec. 14, 2000

Dec. 14, 2000

I uploaded Numeric 17.2.0 but then got errors from Sourceforge's web pages for actually releasing it. I'm going to wait a day or two and try again. I may be forced to renumber around the one that is already there. I don't think users can actually see this file yet. CVS is up to date with what will become 17.2.? when I finally succeed.

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Tutorial in Numerical Python? (fwd)
by Fredrik Stenberg Dec. 13, 2000

Dec. 13, 2000

Hi, I took the liberty to forward your email to numpy-discussion(a)lists.sourceforge.net. The only document i know of is located at the Python homepage http://numpy.sourceforge.net. /fredrik ---------- Forwarded message ---------- Date: 13 Dec 2000 11:27:08 +0000 From: José Luis Gómez Dans <j.l.gomez-dans(a)sheffield.ac.uk> Newsgroups: comp.lang.python Subject: Tutorial in Numerical Python? Hi, I am wondering whether such a thing exists. Is there a nice tutorial for NumPy that guides you through the basic steps? Say, a little hands-on introduction to Linear Algebra, Transforms and possibly the inclusion of some of the graphic modules? There are some willing students to be converted around these parts, and a hands-on tutorial would be great. Unfortunately, I am a beginner in these waters myself, but can see the opportunity for this. Thanks in advance, José -- José L Gómez Dans PhD student Tel: +44 114 222 5582 Radar & Communications Group FAX; +44 870 132 2990 Department of Electronic Engineering University of Sheffield UK

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matrix file format
by Peter I. Hansen Dec. 12, 2000

Dec. 12, 2000

Hi, I'm trying to find out what format a matrix input file should have in numpy. example : I have the matrix : [[1 2 3 4 5 6 7 8 9]] and want to read it to nympy from a text-filen that is easy for a user to generate in an editor. Can you tell me how to do that. I read the manual and it didnøt given much af on idea. I thank you in advance Peter I. Hansen

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