Mailman 3 June 2006 - NumPy-Discussion

immediate fill after empty gives None.
by George Nurser 30 Jun '06

30 Jun '06

Have I done something silly here, or is this a bug? Opteron 64-bit, r2631 SVN. In [4]: depths_s2 = empty(shape=(5,),dtype=float) In [5]: depths_s2.fill(2.e5) In [6]: depths_s2 Out[6]: array([ 200000., 200000., 200000., 200000., 200000.]) In [11]: depths_s2 = (empty(shape=(5,),dtype=float)).fill(2.e5) In [12]: print depths_s2 None --George Nurser.

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Core dump in numpy 0.9.6
by Robert Lupton 30 Jun '06

30 Jun '06

Here's an easy coredump: x = numpy.arange(10, dtype="f"); y = numpy.array(len(x), dtype="F"); y.imag += x Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_PROTECTION_FAILURE at address: 0x00000000 PyArray_CompareLists (l1=0x0, l2=0x1841618, n=1) at numpy/core/src/ multiarraymodule.c:132 132 if (l1[i] != l2[i]) return 0; (gdb) where #0 PyArray_CompareLists (l1=0x0, l2=0x1841618, n=1) at numpy/core/ src/multiarraymodule.c:132 #1 0x02a377d8 in PyUFunc_GenericFunction (self=0x538d40, args=0x2db3c88, mps=0xbfffd9c8) at numpy/core/src/ufuncobject.c:968 #2 0x02a39210 in ufunc_generic_call (self=0x538d40, args=0x2db3c88) at numpy/core/src/ufuncobject.c:2635 #3 0x000243bc in PyObject_CallFunction (callable=0x538d40, format=0x0) at Objects/abstract.c:1756 #4 0x0001f8cc in PyNumber_InPlaceAdd (v=0x565800, w=0x572540) at Objects/abstract.c:740 R

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python spherepack wrapper
by Jeff Whitaker 29 Jun '06

29 Jun '06

Hi All: For those of you who have a need for spherical harmonic transforms in python, I've updated my spherepack (http://www.cisl.ucar.edu/css/software/spherepack/) wrapper for numpy. Docs at http://www.cdc.noaa.gov/people/jeffrey.s.whitaker/python/spharm.html. If you have numpy and a fortran compiler supported by numpy.f2py, all you need to do is run 'python setup.py install'. -Jeff -- Jeffrey S. Whitaker Phone : (303)497-6313 Meteorologist FAX : (303)497-6449 NOAA/OAR/PSD R/PSD1 Email : Jeffrey.S.Whitaker(a)noaa.gov 325 Broadway Office : Skaggs Research Cntr 1D-124 Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg

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We *will* move the mailing list to scipy.org
by Robert Kern 29 Jun '06

29 Jun '06

With a vote of 14 to 2 (and about 400 hundred implicit "I don't care one way or the other"), the new ads, and the recent problems with Sourceforge bouncing or delaying GMail messages, I intend to move the mailing list from Sourceforge to scipy.org in short order. If you have strong objections to this move, this is your last chance to voice them. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco

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incorporating C/C++ code
by Joris De Ridder 29 Jun '06

29 Jun '06

Hi, For heavy number crunching I would like to include C and/or C++ functions in my NumPy programs. They should have/give NumPy arrays as input/output. On http://www.scipy.org/Topical_Software I find several suggestions to wrap C/C++ code: SWIG, weave, Pyrex, Instant, ... but it's quite difficult for me to have an idea which one I can/should use. So, a few questions: Any suggestion for which package I should use? Does this heavily depend for which purpose I want to use it? Where can I find the docs for Weave? I find several links on the internet pointing to http://www.scipy.org/documentation/weave for more info, but there is nothing anymore. Thanks in advance, Joris Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

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Recarray attributes writeable
by Erin Sheldon 29 Jun '06

29 Jun '06

Hi everyone - (this is my fourth try in the last 24 hours to post this. Apparently, the gmail smtp server is in the blacklist!! this is bad). Anyway - Recarrays have convenience attributes such that fields may be accessed through "." in additioin to the "field()" method. These attributes are designed for read only; one cannot alter the data through them. Yet they are writeable: >>> tr=numpy.recarray(10, formats='i4,f8,f8', names='id,ra,dec') >>> tr.field('ra')[:] = 0.0 >>> tr.ra array([ 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.]) >>> tr.ra = 3 >>> tr.ra 3 >>> tr.field('ra') array([ 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.]) I feel this should raise an exception, just as with trying to write to the "size" attribute. Any thoughts? Erin

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min/max not exported in "from numpy import *"
by Zhang Le 29 Jun '06

29 Jun '06

Hi, I'm using 0.9.8 and find numpy.ndarray.min() is not exported to global space when doing a from numpy import * In [1]: from numpy import * In [2]: help min ------> help(min) Help on built-in function min in module __builtin__: min(...) min(sequence) -> value min(a, b, c, ...) -> value With a single sequence argument, return its smallest item. With two or more arguments, return the smallest argument. Also numpy.ndarray.max() is not available too. But the built-in sum() is replaced by numpy.ndarray.sum() as expected. Is this a bug or just intended to do so and user has to use numpy.ndarray.min() explicitly? Cheers, Zhang Le

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trouble on tru64
by N Shimizu 29 Jun '06

29 Jun '06

Hi everyone, I tried to build numpy 0.9.8 on compaq alpha tru64 UNIX v5.1 with gcc 4.0.2, but I encounterd the compilation trouble. The error message is the following. Do you have any suggestion? Thank you in advance. Shimizu. numpy/core/src/umathmodule.c.src: In function 'nc_floor_quotl': numpy/core/src/umathmodule.c.src:600: warning: implicit declaration of function 'floorl' numpy/core/src/umathmodule.c.src:600: warning: incompatible implicit declaration of built-in fu nction 'floorl' .... numpy/core/src/umathmodule.c.src: In function 'LONGDOUBLE_floor_divide': numpy/core/src/umathmodule.c.src:1050: warning: incompatible implicit declaration of built-in f unction 'floorl' numpy/core/src/umathmodule.c.src: In function 'CLONGDOUBLE_absolute': numpy/core/src/umathmodule.c.src:1319: warning: incompatible implicit declaration of built-in f unction 'sqrtl' .... build/src.osf1-V5.1-alpha-2.4/numpy/core/__umath_generated.c: At top level: build/src.osf1-V5.1-alpha-2.4/numpy/core/__umath_generated.c:15: error: 'acosl' undeclared here (not in a function) build/src.osf1-V5.1-alpha-2.4/numpy/core/__umath_generated.c:18: error: 'acoshf' undeclared her e (not in a function) ...

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Should cholesky return upper or lower triangular matrix?
by Keith Goodman 29 Jun '06

29 Jun '06

Isn't the Cholesky decomposition by convention an upper triangular matrix? I noticed, by porting Octave code, that linalg.cholesky returns the lower triangular matrix. References: http://mathworld.wolfram.com/CholeskyDecomposition.html http://www.mathworks.com/access/helpdesk/help/techdoc/ref/chol.html

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explanation of 'order' parameter for reshape
by Glen W. Mabey 29 Jun '06

29 Jun '06

Hello, It seems that the 'order' parameter is not explained neither in the docstring nor in "Guide to NumPy". I'm guessing that the alternative to the default value of 'C' would be 'Fortran'? Thanks, Glen

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