Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Charles R Harris
On Wed, Oct 15, 2008 at 10:41 PM, Charles R Harris < [EMAIL PROTECTED]> wrote: > OK, I take this as a go ahead with the proviso that it's my problem. The > big question is naming. Scipy has > > lu > lu_factor > lu_solve > > cholesky > > cho_factor > cho_solve > > The code for lu and lu_factor isn'

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Charles R Harris
OK, I take this as a go ahead with the proviso that it's my problem. The big question is naming. Scipy has lu lu_factor lu_solve cholesky cho_factor cho_solve The code for lu and lu_factor isn't the same, although they both look to call the same underlying function; the same is true of the chole

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Brian Granger
> If LU is already part of lapack_lite and somebody is willing to put in > the work to expose the functionality to the end user in a reasonable > way, then I think it should be added. +1 ___ Numpy-discussion mailing list Numpy-discussion@scipy.org http:/

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Travis E. Oliphant
Charles R Harris wrote: > > > I would just add the bits that are already there and don't add any > extra dependencies, i.e., they are there when numpy is built without > ATLAS or other external packages. The determinant function in linalg > uses the LU decomposition, so I don't see why that shou

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Stéfan van der Walt
2008/10/15 Robert Kern <[EMAIL PROTECTED]>: > Which bits? The current set has worked fine for more than 10 years. I'm surprised no-one has requested the LU decomposition in NumPy before -- it is a fundamental building block in linear algebra. I think it is going too far, stating that NumPy's line

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Robert Kern
On Wed, Oct 15, 2008 at 15:33, Charles R Harris <[EMAIL PROTECTED]> wrote: > > On Wed, Oct 15, 2008 at 2:26 PM, Robert Kern <[EMAIL PROTECTED]> wrote: >> >> On Wed, Oct 15, 2008 at 15:21, Charles R Harris >> <[EMAIL PROTECTED]> wrote: >> > >> > On Wed, Oct 15, 2008 at 2:04 PM, Robert Kern <[EMAIL P

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Alan G Isaac
On 10/15/2008 4:26 PM Robert Kern apparently wrote: > Which bits? Those in lapack_lite? Alan Isaac ___ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Charles R Harris
On Wed, Oct 15, 2008 at 2:26 PM, Robert Kern <[EMAIL PROTECTED]> wrote: > On Wed, Oct 15, 2008 at 15:21, Charles R Harris > <[EMAIL PROTECTED]> wrote: > > > > On Wed, Oct 15, 2008 at 2:04 PM, Robert Kern <[EMAIL PROTECTED]> > wrote: > >> > >> On Wed, Oct 15, 2008 at 14:49, Charles R Harris > >> <[

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Robert Kern
On Wed, Oct 15, 2008 at 15:21, Charles R Harris <[EMAIL PROTECTED]> wrote: > > On Wed, Oct 15, 2008 at 2:04 PM, Robert Kern <[EMAIL PROTECTED]> wrote: >> >> On Wed, Oct 15, 2008 at 14:49, Charles R Harris >> <[EMAIL PROTECTED]> wrote: >> > >> > On Wed, Oct 15, 2008 at 1:06 PM, Robert Kern <[EMAIL P

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Charles R Harris
On Wed, Oct 15, 2008 at 2:04 PM, Robert Kern <[EMAIL PROTECTED]> wrote: > On Wed, Oct 15, 2008 at 14:49, Charles R Harris > <[EMAIL PROTECTED]> wrote: > > > > On Wed, Oct 15, 2008 at 1:06 PM, Robert Kern <[EMAIL PROTECTED]> > wrote: > >> > >> On Wed, Oct 15, 2008 at 00:23, Charles R Harris > >> <[

Re: [Numpy-discussion] Array printing differences between 64- and 32-bit platforms

2008-10-15 Thread Charles R Harris
On Wed, Oct 15, 2008 at 10:52 AM, Ken Basye <[EMAIL PROTECTED]> wrote: > Hi Folks, > In porting some code to a 64-bit machine, I ran across the following > issue. > On the 64-bit machine, an array with dtype=int32 prints the dtype > explicitly, whereas on > a 32 bit machine it doesn't. The same

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Robert Kern
On Wed, Oct 15, 2008 at 14:49, Charles R Harris <[EMAIL PROTECTED]> wrote: > > On Wed, Oct 15, 2008 at 1:06 PM, Robert Kern <[EMAIL PROTECTED]> wrote: >> >> On Wed, Oct 15, 2008 at 00:23, Charles R Harris >> <[EMAIL PROTECTED]> wrote: >> > Hi All, >> > >> > numpy.linalg has qr and cholesky factoriz

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Robert Kern
On Wed, Oct 15, 2008 at 14:43, Stéfan van der Walt <[EMAIL PROTECTED]> wrote: > 2008/10/15 Robert Kern <[EMAIL PROTECTED]>: >>> numpy.linalg has qr and cholesky factorizations, but LU factorization is >>> only available in scipy. That doesn't seem quite right. I think is would >>> make sense to inc

Re: [Numpy-discussion] dtype comparison and hashing

2008-10-15 Thread Robert Kern
On Wed, Oct 15, 2008 at 02:20, Geoffrey Irving <[EMAIL PROTECTED]> wrote: > Hello, > > Currently in numpy comparing dtypes for equality with == does an > internal PyArray_EquivTypes check, which means that the dtypes NPY_INT > and NPY_LONG compare as equal in python. However, the hash function > f

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Charles R Harris
On Wed, Oct 15, 2008 at 1:06 PM, Robert Kern <[EMAIL PROTECTED]> wrote: > On Wed, Oct 15, 2008 at 00:23, Charles R Harris > <[EMAIL PROTECTED]> wrote: > > Hi All, > > > > numpy.linalg has qr and cholesky factorizations, but LU factorization is > > only available in scipy. That doesn't seem quite r

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Stéfan van der Walt
2008/10/15 Robert Kern <[EMAIL PROTECTED]>: >> numpy.linalg has qr and cholesky factorizations, but LU factorization is >> only available in scipy. That doesn't seem quite right. I think is would >> make sense to include the LU factorization in numpy among the basic linalg >> operations, and probab

Re: [Numpy-discussion] memory usage (Emil Sidky)

2008-10-15 Thread Perry Greenfield
When you slice an array, you keep the original array in memory until the slice is deleted. The slice uses the original array memory and is not a copy. The second example explicitly makes a copy. Perry On Oct 15, 2008, at 2:31 PM, emil wrote: > >> Huang-Wen Chen wrote: >>> Robert Kern wrote:

Re: [Numpy-discussion] LU factorization?

2008-10-15 Thread Robert Kern
On Wed, Oct 15, 2008 at 00:23, Charles R Harris <[EMAIL PROTECTED]> wrote: > Hi All, > > numpy.linalg has qr and cholesky factorizations, but LU factorization is > only available in scipy. That doesn't seem quite right. I think is would > make sense to include the LU factorization in numpy among th

[Numpy-discussion] memory usage (Emil Sidky)

2008-10-15 Thread emil
> Huang-Wen Chen wrote: >> Robert Kern wrote: from numpy import * for i in range(1000): a = random.randn(512**2) b = a.argsort(kind='quick') >>> Can you try upgrading to numpy 1.2.0? On my machine with numpy 1.2.0 >>> on OS X, the memory usage is stable. >>> >> I tried t

[Numpy-discussion] Array printing differences between 64- and 32-bit platforms

2008-10-15 Thread Ken Basye
Hi Folks, In porting some code to a 64-bit machine, I ran across the following issue. On the 64-bit machine, an array with dtype=int32 prints the dtype explicitly, whereas on a 32 bit machine it doesn't. The same is true for dtype=intc (since 'intc is int32' --> True), and the converse is tr

Re: [Numpy-discussion] var bias reason?

2008-10-15 Thread Charles R Harris
On Wed, Oct 15, 2008 at 9:19 AM, David Cournapeau <[EMAIL PROTECTED]>wrote: > On Wed, Oct 15, 2008 at 11:45 PM, Travis E. Oliphant > <[EMAIL PROTECTED]> wrote: > > Gabriel Gellner wrote: > >> Some colleagues noticed that var uses biased formula's by default in > numpy, > >> searching for the reaso

Re: [Numpy-discussion] var bias reason?

2008-10-15 Thread Bruce Southey
Hi, While I disagree, I really do not care because this is documented. But perhaps a clear warning is need at the start so it clear what the default ddof means instead of it being buried in the Notes section. Also I am surprised that you did not directly reference the Stein estimator (your mi

Re: [Numpy-discussion] var bias reason?

2008-10-15 Thread Gabriel Gellner
On Wed, Oct 15, 2008 at 09:45:39AM -0500, Travis E. Oliphant wrote: > Gabriel Gellner wrote: > > Some colleagues noticed that var uses biased formula's by default in numpy, > > searching for the reason only brought up: > > > > http://article.gmane.org/gmane.comp.python.numeric.general/12438/match=v

Re: [Numpy-discussion] var bias reason?

2008-10-15 Thread Scott Ransom
Me too. S On Wednesday 15 October 2008 11:31:44 am Paul Barrett wrote: > I'm behind Travis on this one. > > -- Paul > > On Wed, Oct 15, 2008 at 11:19 AM, David Cournapeau <[EMAIL PROTECTED]> wrote: > > On Wed, Oct 15, 2008 at 11:45 PM, Travis E. Oliphant > > > > <[EMAIL PROTECTED]> wrote: > >>

Re: [Numpy-discussion] var bias reason?

2008-10-15 Thread Paul Barrett
I'm behind Travis on this one. -- Paul On Wed, Oct 15, 2008 at 11:19 AM, David Cournapeau <[EMAIL PROTECTED]> wrote: > On Wed, Oct 15, 2008 at 11:45 PM, Travis E. Oliphant > <[EMAIL PROTECTED]> wrote: >> Gabriel Gellner wrote: >>> Some colleagues noticed that var uses biased formula's by default

Re: [Numpy-discussion] var bias reason?

2008-10-15 Thread David Cournapeau
On Wed, Oct 15, 2008 at 11:45 PM, Travis E. Oliphant <[EMAIL PROTECTED]> wrote: > Gabriel Gellner wrote: >> Some colleagues noticed that var uses biased formula's by default in numpy, >> searching for the reason only brought up: >> >> http://article.gmane.org/gmane.comp.python.numeric.general/12438

Re: [Numpy-discussion] var bias reason?

2008-10-15 Thread Travis E. Oliphant
Gabriel Gellner wrote: > Some colleagues noticed that var uses biased formula's by default in numpy, > searching for the reason only brought up: > > http://article.gmane.org/gmane.comp.python.numeric.general/12438/match=var+bias > > which I totally agree with, but there was no response? Any reason

[Numpy-discussion] var bias reason?

2008-10-15 Thread Gabriel Gellner
Some colleagues noticed that var uses biased formula's by default in numpy, searching for the reason only brought up: http://article.gmane.org/gmane.comp.python.numeric.general/12438/match=var+bias which I totally agree with, but there was no response? Any reason for this? Is there any way I can

Re: [Numpy-discussion] how to save a large array into a file quickly

2008-10-15 Thread Alan G Isaac
On 10/14/2008 9:23 PM frank wang apparently wrote: > I have a large ndarray that I want to dump to a file. I know that I can > use a for loop to write one data at a time. Since Python is a very > powerfully language, I want to find a way that will dump the data fast > and clean. The data can be

Re: [Numpy-discussion] Any numpy trick for my problem ?

2008-10-15 Thread Stéfan van der Walt
Hi Uwe 2008/10/15 Uwe Schmitt <[EMAIL PROTECTED]>: > I got a matrix of 2100 lines, and I want to calculate blockwise mean > vectors. > Each block consists of 10 consecutive rows. > > My code looks like this: > > rv = [] > for i in range(0, 2100, 10): > rv.append( mean(matrix[i:i+10], ax

Re: [Numpy-discussion] how to save a large array into a file quickly

2008-10-15 Thread Steve Schmerler
On Oct 14 15:29 -1000, Eric Firing wrote: > frank wang wrote: > > Hi, > > > > I have a large ndarray that I want to dump to a file. I know that I can > > use a for loop to write one data at a time. Since Python is a very > > powerfully language, I want to find a way that will dump the data fas

Re: [Numpy-discussion] Any numpy trick for my problem ?

2008-10-15 Thread Uwe Schmitt
That's cool. Thanks for your fast answer. Greetings, Uwe On 15 Okt., 12:56, "Charles R Harris" <[EMAIL PROTECTED]> wrote: > On Wed, Oct 15, 2008 at 4:47 AM, Uwe Schmitt <[EMAIL PROTECTED] > > > > > wrote: > > Hi, > > > I got a matrix of 2100 lines, and I want to calculate  blockwise mean > > vect

Re: [Numpy-discussion] Any numpy trick for my problem ?

2008-10-15 Thread Charles R Harris
On Wed, Oct 15, 2008 at 4:47 AM, Uwe Schmitt <[EMAIL PROTECTED] > wrote: > Hi, > > I got a matrix of 2100 lines, and I want to calculate blockwise mean > vectors. > Each block consists of 10 consecutive rows. > > My code looks like this: > > rv = [] > for i in range(0, 2100, 10): > rv.a

[Numpy-discussion] Any numpy trick for my problem ?

2008-10-15 Thread Uwe Schmitt
Hi, I got a matrix of 2100 lines, and I want to calculate blockwise mean vectors. Each block consists of 10 consecutive rows. My code looks like this: rv = [] for i in range(0, 2100, 10): rv.append( mean(matrix[i:i+10], axis=0)) return array(rv) Is there a more elegant and may

Re: [Numpy-discussion] memory usage

2008-10-15 Thread Vincent Schut
Huang-Wen Chen wrote: > Robert Kern wrote: >>> from numpy import * >>> for i in range(1000): >>> a = random.randn(512**2) >>> b = a.argsort(kind='quick') >> Can you try upgrading to numpy 1.2.0? On my machine with numpy 1.2.0 >> on OS X, the memory usage is stable. >> > I tried the code frag

[Numpy-discussion] dtype comparison and hashing

2008-10-15 Thread Geoffrey Irving
Hello, Currently in numpy comparing dtypes for equality with == does an internal PyArray_EquivTypes check, which means that the dtypes NPY_INT and NPY_LONG compare as equal in python. However, the hash function for dtypes reduces id(), which is therefore inconsistent with ==. Unfortunately I can'