Re: [Numpy-discussion] numpy ufuncs and COREPY - any info?

2009-05-28 Thread David Cournapeau
Andrew Friedley wrote: > David Cournapeau wrote: > >> Francesc Alted wrote: >> >>> No, that seems good enough. But maybe you can present results in >>> cycles/item. >>> This is a relatively common unit and has the advantage that it does not >>> depend >>> on the frequency of your cor

Re: [Numpy-discussion] Nested recarrays with subarrays and loadtxt: a bug in loadtxt?

2009-05-28 Thread Pierre GM
On May 27, 2009, at 7:29 PM, Stéfan van der Walt wrote: > Hi Fernando > > 2009/5/28 Fernando Perez : >> Well, since dtypes allow for nesting full arrays in this fashion, >> where I can say that the 'block' field can have (2,3) shape, it seems >> like it would be nice to be able to express this ne

Re: [Numpy-discussion] sparse matrix dot product

2009-05-28 Thread Nathan Bell
On Thu, May 28, 2009 at 10:14 AM, Nicolas Rougier wrote: > > Obviously, the last computation is not a dot product, but I got no > warning at all. Is that the expected behavior ? > Sparse matrices make no attempt to work with numpy functions like dot(), so I'm not sure what is happening there. >

Re: [Numpy-discussion] example reading binary Fortran file

2009-05-28 Thread David Froger
Sorry, I still don't understand how to use FortranFile ... The fortran code program writeArray implicit none integer,parameter:: nx=2,ny=5 real(4),dimension(nx,ny):: ux,uy,p integer :: i,j do i = 1,nx do j = 1,ny ux(i,j) = 100. + j+(i-1.)*10. uy(i,j) = 200. + j+

Re: [Numpy-discussion] Benchmak on record arrays

2009-05-28 Thread Francesc Alted
A Wednesday 27 May 2009 17:31:20 Nicolas Rougier escrigué: > Hi, > > I've written a very simple benchmark on recarrays: > > import numpy, time > > Z = numpy.zeros((100,100), dtype=numpy.float64) > Z_fast = numpy.zeros((100,100), dtype=[('x',numpy.float64), > ('y',numpy.int32)]) > Z_slow = numpy.zer

Re: [Numpy-discussion] example reading binary Fortran file

2009-05-28 Thread Neil Martinsen-Burrell
On 2009-05-28 12:11 , David Froger wrote: > Thank you very much :-) Things should be cleared up now on the wiki as well. Peace, -Neil ___ Numpy-discussion mailing list Numpy-discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion

Re: [Numpy-discussion] example reading binary Fortran file

2009-05-28 Thread David Froger
Thank you very much :-) 2009/5/28 Neil Martinsen-Burrell > On 2009-05-28 09:32 , David Froger wrote: > >> Hy Neil Martinsen-Burrell, >> >> I'm trying the FortranFile class, >> http://www.scipy.org/Cookbook/FortranIO/FortranFile >> >> It looks like there are some bug in the last revision (7): >>

Re: [Numpy-discussion] example reading binary Fortran file

2009-05-28 Thread Neil Martinsen-Burrell
On 2009-05-28 09:32 , David Froger wrote: Hy Neil Martinsen-Burrell, I'm trying the FortranFile class, http://www.scipy.org/Cookbook/FortranIO/FortranFile It looks like there are some bug in the last revision (7): * There are errors cause by lines 60,61,63 in * There are indentation e

[Numpy-discussion] convert between structure arrays with different record orderings?

2009-05-28 Thread roger peppe
hi, sorry, i'm new to the list, and if this is a frequently asked question, please point me in the right direction. say, for some reason i've got two numpy structure arrays that both contain the same fields with the same types but in a different order, is there a simple way to convert one to the

Re: [Numpy-discussion] example reading binary Fortran file

2009-05-28 Thread David Froger
Hy Neil Martinsen-Burrell, I'm trying the FortranFile class, http://www.scipy.org/Cookbook/FortranIO/FortranFile It looks like there are some bug in the last revision (7): * There are errors cause by lines 60,61,63 in * There are indentation errors on lines 97 and 113. ___

Re: [Numpy-discussion] sparse matrix dot product

2009-05-28 Thread Sebastian Walter
I'd be interested to see the benchmark ;) On Thu, May 28, 2009 at 4:14 PM, Nicolas Rougier wrote: > > Hi, > > I'm now testing dot product and using the following: > > import numpy as np, scipy.sparse as sp > > A = np.matrix(np.zeros((5,10))) > B = np.zeros((10,1)) > print (A*B).shape > print np

Re: [Numpy-discussion] Benchmak on record arrays

2009-05-28 Thread Nicolas Rougier
I just created the account. Nicolas On Thu, 2009-05-28 at 11:21 +0200, Stéfan van der Walt wrote: > Hi Nicolas > > 2009/5/27 Nicolas Rougier : > > No, I don't have permission to edit. > > Thanks for helping out with the docs! Please create an account on > docs.scipy.org and give me a shout

[Numpy-discussion] sparse matrix dot product

2009-05-28 Thread Nicolas Rougier
Hi, I'm now testing dot product and using the following: import numpy as np, scipy.sparse as sp A = np.matrix(np.zeros((5,10))) B = np.zeros((10,1)) print (A*B).shape print np.dot(A,B).shape A = sp.csr_matrix(np.zeros((5,10))) B = sp.csr_matrix((10,1)) print (A*B).shape print np.dot(A,B).shape

Re: [Numpy-discussion] numpy ufuncs and COREPY - any info?

2009-05-28 Thread Andrew Friedley
David Cournapeau wrote: > Francesc Alted wrote: >> No, that seems good enough. But maybe you can present results in >> cycles/item. >> This is a relatively common unit and has the advantage that it does not >> depend >> on the frequency of your cores. Sure, cycles is fine, but I'll argue th

Re: [Numpy-discussion] Benchmak on record arrays

2009-05-28 Thread Stéfan van der Walt
Hi Nicolas 2009/5/27 Nicolas Rougier : > No, I don't have permission to edit. Thanks for helping out with the docs! Please create an account on docs.scipy.org and give me a shout when you're done. Cheers Stéfan ___ Numpy-discussion mailing list Numpy-

Re: [Numpy-discussion] Numpy vs PIL in image statistics

2009-05-28 Thread cp
> I don't know anything about PIL and its implementation, but I would not > be surprised if the cost is mostly accessing items which are not > contiguous in memory and bounds checking ( to check where you are in the > subimage). Conditional inside loops often kills performances, and the > actual co

Re: [Numpy-discussion] Numpy vs PIL in image statistics

2009-05-28 Thread David Cournapeau
cp wrote: >>> The image I tested initially is 2000x2000 RGB tif ~11mb in size. >>> > I continued testing, with the initial PIL approach > and 3 alternative numpy scripts: > > #Script 1 - indexing > for i in range(10): > imarr[:,:,0].mean() > imarr[:,:,1].mean() > imarr[:,:,2].mea

Re: [Numpy-discussion] Numpy vs PIL in image statistics

2009-05-28 Thread cp
>> The image I tested initially is 2000x2000 RGB tif ~11mb in size. I continued testing, with the initial PIL approach and 3 alternative numpy scripts: #Script 1 - indexing for i in range(10): imarr[:,:,0].mean() imarr[:,:,1].mean() imarr[:,:,2].mean() #Script 2 - slicing for i in ran

Re: [Numpy-discussion] Failure with 1.3

2009-05-28 Thread Matthieu Brucher
> This is the first report. I'll guess it is related to icc. What happens if > you use gcc? Indeed, with gcc4.1, the error isn't there. Matthieu -- Information System Engineer, Ph.D. Website: http://matthieu-brucher.developpez.com/ Blogs: http://matt.eifelle.com and http://blog.developpez.com/?b

Re: [Numpy-discussion] numpy ufuncs and COREPY - any info?

2009-05-28 Thread David Cournapeau
Francesc Alted wrote: > A Tuesday 26 May 2009 15:14:39 Andrew Friedley escrigué: > >> David Cournapeau wrote: >> >>> Francesc Alted wrote: >>> Well, it is Andrew who should demonstrate that his measurement is correct, but in principle, 4 cycles/item *should* be feasible whe