Mailman 3 September 2006 - NumPy-Discussion

general version of repmat?
by Bill Baxter 23 Sep '06

23 Sep '06

Is there some way to get the equivalent of repmat() for ndim == 1 and ndim >2. For ndim == 1, repmat always returns a 2-d array, instead of remaining 1-d. For ndim >2, repmat just doesn't work. Maybe we could add a 'reparray', with the signature: reparray(A, repeats, axis=None) where repeats is a scalar or a sequence. If 'repeats' is a scalar then the matrix is duplicated along 'axis' that many times. If 'repeats' is a sequence of length N, then A is duplicated repeats[i] times along axis[i]. If axis is None then it is assumed to be (0,1,2...N). Er that's not quite complete, because it doesn't specify what happens when you reparray an array to a higher dimension, like a 1-d to a 3-d. Like reparray([1,2], (2,2,2)). I guess the axis parameter could have some 'newaxis' entries to accomodate that. --bb

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[Numpy-discussion] 非财务经理的财务管理沙盘模拟课程
by "9月28-29日/上海" 23 Sep '06

23 Sep '06

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TPM全员设备维护与管理
by tpm 23 Sep '06

23 Sep '06

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TPM全员设备维护与管理
by tpm 23 Sep '06

23 Sep '06

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Rationale for atleast_3d
by Bill Baxter 23 Sep '06

23 Sep '06

26 weeks, 4 days, 2 hours and 9 minutes ago, Zdeněk Hurák asked why atleast_3d acts the way it does: http://article.gmane.org/gmane.comp.python.numeric.general/4382/match=atlea… He doesn't seem to have gotten any answers. And now I'm wondering the same thing. Anyone have any idea? --bb

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take behaviour has changed
by Christian Kristukat 23 Sep '06

23 Sep '06

Hi, from 1.0b1 to 1.0rc1 the default behaviour of take seems to have changed when omitting the axis argument: In [13]: a = reshape(arange(12),(3,4)) In [14]: take(a,[2,3]) Out[14]: array([2, 3]) In [15]: take(a,[2,3],1) Out[15]: array([[ 2, 3], [ 6, 7], [10, 11]]) Is this intended? Christian

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Question about recarray
by Lionel Roubeyrie 22 Sep '06

22 Sep '06

Hi all, Is it possible to put masked values into recarrays, I need a array with heterogenous types of datas (datetime objects in the first col, all others are float) but with missing values in some records. For the moment, I don't find any solution for that. I have tried with arrays of dtype=object, but I have problem when I want to compute min, max, ... with an error like: TypeError: function not supported for these types, and can't coerce safely to supported types. thanks -- Lionel Roubeyrie - lroubeyrie(a)limair.asso.fr LIMAIR http://www.limair.asso.fr

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reading large files
by Svein-Erik.Hamran＠ffi.no 22 Sep '06

22 Sep '06

I would like to read files >2Gbyte. From earlier posting I believed it should be possible with python 2.5. I am getting MemoryError when trying to read a file larger than 2Gb. I am using python2.5 and numpy1.0rc1. Any solution to the problem? SEH

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Putmask/take ?
by PGM 22 Sep '06

22 Sep '06

Folks, I'm running into the following problem with putmask on take. >>> import numpy >>> x = N.arange(12.) >>> m = [1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1] >>> i = N.nonzero(m)[0] >>> w = N.array([-1, -2, -3, -4.]) >>> x.putmask(w,m) >>> x.take(i) >>> N.allclose(x.take(i),w) False I'm wondering ifit is intentional, or if it's a problem on my build (1.0b5), or if somebody experienced it as well. Thanks a lot for your input. P.

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please change mean to use dtype=float
by Sebastian Haase 22 Sep '06

22 Sep '06

Hello all, I just had someone from my lab coming to my desk saying: "My god - SciPy is really stupid .... An array with only positive numbers claims to have a negative mean !! "? I was asking about this before ... the reason was of course that her array was of dtype int32 and had many large values to cause an overflow (wrap around) . Now that the default for axis is None (for all functions having an axis argument), can we please change dtype to default to float64 !? It is really a very confusing and shocking result to get a negative mean on all positive values. It has been stated here before that numpy should target the "scientist" rather than the programmers ... I would argue that mean() almost always requires the precision of "double" (float64) to produce usable results. Please consider this change before the 1.0 release ... Thanks, Sebastian Haase

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Always using scientific notation to print
by Brian Granger 22 Sep '06

22 Sep '06

I want to be able to print an array in scientific notation. I have seen the set_printoptions() functions, but it doesn't really have an option for *always* using scientific notation. Can this be done? How? Thanks Brian

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bug in oldnumeric module
by Scott Ransom 22 Sep '06

22 Sep '06

argmin is currently defined as using the argmax method! From numpy/oldnumeric/functions.py def argmin(x, axis=-1): return N.argmax(x, axis) Scott -- Scott M. Ransom Address: NRAO Phone: (434) 296-0320 520 Edgemont Rd. email: sransom(a)nrao.edu Charlottesville, VA 22903 USA GPG Fingerprint: 06A9 9553 78BE 16DB 407B FFCA 9BFA B6FF FFD3 2989

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intellectual federation
by Hal Giles 22 Sep '06

22 Sep '06

Feisalintroduced us one by one, and Auda with a measured word seemed toregister each person. I said I was a simple man who disliked servants about him. The walls each sidewere of regular bands of sandstone, streaked red in many shades. Jealousy, superadded to inefficiency, would be the outcome. The walls each sidewere of regular bands of sandstone, streaked red in many shades. They expected him next day; so wepassed two nights in this strange-coloured, echoing place. At first it was two and two, but theothers joined, till they were six abreast. Each required to be consulted on the details of ourgoing, and where and when we should halt. The edges of the cliffs about us were clipped strangely,like fantastic parapets. The fluency had a lack of grammar, which made my talk aperpetual adventure for my hearers. Therefore it seemed fit to the boyMohammed to run races. Sheslipped, so that he crashed off and broke an arm. The Arab war was geographical, and the Turkish Army an accident. Thirdly, that their virtue lay in depth, not inface. NASIR, AUDA, AND I SET OFF TOGETHER ON THE LONG RIDE. They expected him next day; so wepassed two nights in this strange-coloured, echoing place. The aeroplanes from it had flown uphere and were established. Wadi Osman to-day was less irregular in course, and broadened slowly. Everybody took the offer, and the camels set offin a mob. The aeroplanes from it had flown uphere and were established. Therefore it seemed fit to the boyMohammed to run races. Of the number of dead Turks he could give no account: they didnot enter the register. There entered a tall, strong figure, with a haggard face,passionate and tragic. Or was it merely that long ago we had seen freshgrass growing in the spring? The last part of the marchwas after dark, and when we stopped, Arslan was missing. We were now on the limestoneof the Shefa crest. If his performancewas one-half his desire, we should be prosperous and fortunate. So I judged mywork in Wadi Ais sufficiently done, and well done. Everybody took the offer, and the camels set offin a mob. In prison inEgypt he would cost us food and guards. A short hour later we stopped at the tents of a wife of Dakhil-Allah,for a meal. All he could do for my sake wasto let Daud share the ordained sentence. Mohammed el Kadhi was ourguide, with six Juheina. I was eating my Lords breadwith Turkish teeth! When innocent they were hot andunashamed. If his performancewas one-half his desire, we should be prosperous and fortunate.

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putmask/take ?
by P GM 22 Sep '06

22 Sep '06

Folks, I'm running into the following problem with putmask on take. >>> import numpy >>> x = N.arange(12.) >>> m = [1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1] >>> i = N.nonzero(m)[0] >>> w = N.array([-1, -2, -3, -4.]) >>> x.putmask(w,m) >>> x.take(i) >>> N.allclose(x.take(i),w) False I'm wondering ifit is intentional, or if it's a problem on my build (1.0b5), or if somebody experiences that as well. Thanks a lot for your input. P.

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Re: [Numpy-discussion] 1.0rc1 doesn't seem to work on AMD64
by Peter Bienstman 22 Sep '06

22 Sep '06

Cleaning out and rebuilding did the trick! Thanks, Peter On Thursday 21 September 2006 18:33, numpy-discussion-request(a)lists.sourceforge.net wrote: > Subject: Re: [Numpy-discussion] 1.0rc1 doesn't seem to work on AMD64 > <snip> > > I don't see this running the latest from svn on AMD64 here. Not sayin' > there might not be a problem with rc1, I just don't see it with my sources. > > Python 2.4.3 (#1, Jun 13 2006, 11:46:22) > [GCC 4.1.1 20060525 (Red Hat 4.1.1-1)] on linux2 > Type "help", "copyright", "credits" or "license" for more information. > > >>> import numpy > >>> numpy.version.version > > '1.0.dev3202' > > >>> numpy.version.os.uname() > > ('Linux', 'tethys', '2.6.17-1.2187_FC5', '#1 SMP Mon Sep 11 01:16:59 EDT > 2006', 'x86_64') > > If you are building on Gentoo maybe you could delete the build directory > (and maybe the numpy site package) and rebuild. > > Chuck.

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matrixmultiply moved (release notes?)
by Bill Baxter 22 Sep '06

22 Sep '06

Apparently numpy.matrixmultiply got moved into numpy.oldnumeric.matrixmultiply at some point (or rather ceased to be imported into the numpy namespace). Is there any list of all such methods that got banished? This would be nice to have in the release notes. --bb

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Tests and code documentation
by Charles R Harris 22 Sep '06

22 Sep '06

Travis, A few questions. 1) I can't find any systematic code testing units, although there seem to be tests for regressions and such. Is there a place we should be putting such tests? 2) Any plans for code documentation? I documented some of my stuff with doxygen markups and wonder if we should include a Doxyfile as part of the package. 3) Would you consider breaking out the Converters into a separate .c file for inclusion? The code generator seems to take care of the ordering. Chuck

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change of default dtype
by David Grant 22 Sep '06

22 Sep '06

I noticed that the default dtype for the "ones" and "zeros" functions is now float, whereas it used to be int. Should this be noted at http://www.scipy.org/ReleaseNotes/NumPy_1.0 since it does break code (if you are using the array you creating with ones or zeros as indices into another array). -- David Grant http://www.davidgrant.ca

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numpy 1.0rc1 bdist_rpm fails
by Christian Kristukat 22 Sep '06

22 Sep '06

Hi, on linux I get an error when trying to build a rpm package from numpy 1.0rc1: building extension "numpy.core.umath" sources adding 'build/src.linux-i686-2.4/numpy/core/config.h' to sources. executing numpy/core/code_generators/generate_ufunc_api.py adding 'build/src.linux-i686-2.4/numpy/core/__ufunc_api.h' to sources. creating build/src.linux-i686-2.4/src conv_template:> build/src.linux-i686-2.4/src/umathmodule.c error: src/umathmodule.c.src: No such file or directory error: Bad exit status from /home/ck/testarea/rpm/tmp/rpm-tmp.68597 (%build) RPM build errors: Bad exit status from /home/ck/testarea/rpm/tmp/rpm-tmp.68597 (%build) error: command 'rpmbuild' failed with exit status 1 Christian

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immutable arrays
by Martin Wiechert 22 Sep '06

22 Sep '06

Hi list, I just stumbled accross NPY_WRITEABLE flag. Now I'd like to know if there are ways either from Python or C to make an array temporarily immutable. Thanks, Martin.

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arr.dtype.kind is 'i' for dtype=unit !?
by Sebastian Haase 21 Sep '06

21 Sep '06

Hi, What are the possible values of arr.dtype.kind ? It seems that signed and unsigned are considered to be the same "kind" >>> arr=N.arange(10,dtype=N.uint) >>> arr.dtype.kind 'i' >>> arr.dtype.itemsize 8 (OK - this is just showing off our amd64 linux ;-) ) How can I distinguish signed from unsigned without having to list all possible cases explicitly ? Thanks, Sebastian Haase

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1.0rc1 doesn't seem to work on AMD64
by Peter Bienstman 21 Sep '06

21 Sep '06

Hi, I just installed rc1 on an AMD64 machine. but I get this error message when trying to import it: Python 2.4.3 (#1, Sep 21 2006, 13:06:42) [GCC 4.1.1 (Gentoo 4.1.1)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import numpy Traceback (most recent call last): File "<stdin>", line 1, in ? File "/usr/lib64/python2.4/site-packages/numpy/__init__.py", line 36, in ? import core File "/usr/lib64/python2.4/site-packages/numpy/core/__init__.py", line 7, in ? import numerictypes as nt File "/usr/lib64/python2.4/site-packages/numpy/core/numerictypes.py", line 191, in ? _add_aliases() File "/usr/lib64/python2.4/site-packages/numpy/core/numerictypes.py", line 169, in _add_aliases base, bit, char = bitname(typeobj) File "/usr/lib64/python2.4/site-packages/numpy/core/numerictypes.py", line 119, in bitname char = base[0] IndexError: string index out of range Thanks! Peter

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nan adds lots of whitespace
by Keith Goodman 21 Sep '06

21 Sep '06

NaN adds a lot of whitespace in the representation of a matrix. Without NaN: matrix([[1, 2], [3, 4]]) With NaN: matrix([[ nan, 2. ], [ 3. , 4. ]]) There's enough room for the wikipedia entry for nan.

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sorting -inf, nan, inf
by Keith Goodman 21 Sep '06

21 Sep '06

In what order would you like argsort to sort the values -inf, nan, inf? In numpy 1.0b1 nan is always left where it began: EXAMPLE 1 >> x matrix([[ inf], [ -inf], [ nan]]) >> x[x.argsort(0),:] matrix([[ -inf], [ inf], [ nan]]) EXAMPLE 2 >> x matrix([[ nan], [ inf], [ -inf]]) >> x[x.argsort(0),:] matrix([[ nan], [ -inf], [ inf]]) I would like nan to be in the middle between -inf and inf.

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Division by zero doesn't raise exception in the integer case.
by Charles R Harris 21 Sep '06

21 Sep '06

Travis, Is this intentional? In [77]: arange(5, dtype=int)/0 Out[77]: array([0, 0, 0, 0, 0]) It looks deliberate because all zeros are returned, but it might be better if it raised an exception. Chuck

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NumPy-Discussion September 2006