[Numpy-discussion] defmatrix.py

Hi, Several tests didn't pass due to the recent changes in defmatrix.py. Nils == ERROR: check_matmat (scipy.sparse.tests.test_sparse.test_csc) -- Traceback (

Re: [Numpy-discussion] Is a string a scalar type?

On 3/24/07, Robert Kern <[EMAIL PROTECTED]> wrote: Charles R Harris wrote: > In [10]: isscalar('hello world') > Out[10]: True As far as numpy is concerned, they are. >>> from numpy import * >>> array('hello world') array('hello world', dtype='|S11') Dunno, by that reasoning objects co

Re: [Numpy-discussion] Is a string a scalar type?

On 3/24/07, Robert Kern <[EMAIL PROTECTED]> wrote: Charles R Harris wrote: > In [10]: isscalar('hello world') > Out[10]: True I would say that, intrinsically, yes, strings are constructed as sequences of other things. However, essentially every use case I have for *testing* whether or not somet

[Numpy-discussion] nd_image.affine_transform edge effects

Hi Stéfan, > Agreed, but the aliasing effects isn't not the problem here, as it > should be visible in the input image as well. It's a bit academic now that Zach seems to have found the answer, but I don't think this is true. Aliasing is *present* in the input image, but is simply manifested as

Re: [Numpy-discussion] swig svn commits

OK. So if I understand this correctly, PyArray_EquivTypenums() can't do native byte order checking. But I'm assuming PyArray_EquivTypes() could. Unfortunately, the numpy.i typemaps are based on the enumerated typenums, not PyArray_Descr objects. There are a couple of other places where th

Re: [Numpy-discussion] Is a string a scalar type?

Charles R Harris wrote: > In [10]: isscalar('hello world') > Out[10]: True I would say that, intrinsically, yes, strings are constructed as sequences of other things. However, essentially every use case I have for *testing* whether or not something is a sequence (or inversely, a scalar), I want st

Re: [Numpy-discussion] Is a string a scalar type?

Charles R Harris wrote: > In [10]: isscalar('hello world') > Out[10]: True As far as numpy is concerned, they are. >>> from numpy import * >>> array('hello world') array('hello world', dtype='|S11') -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enig

[Numpy-discussion] Is a string a scalar type?

In [10]: isscalar('hello world') Out[10]: True Chuck ___ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion

[Numpy-discussion] nd_image.affine_transform edge effects

Hi Zach, > Based on my reading of the two excellent Unser papers (both the one > that ndimage's spline code is based on, and the one that Travis > linked to), it seems like a major point of using splines for > interpolation is *better* behavior in the case of non-band-limited > data than the

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Alan G Isaac <[EMAIL PROTECTED]> wrote: On Sat, 24 Mar 2007, Anne Archibald apparently wrote: > Note that taking a vector and left-multiplying it by > a matrix is a very natural operation that won't work any > more if you treat all vectors as if they were row vectors. Can you be mor

Re: [Numpy-discussion] nd_image.affine_transform edge effects

On Sat, Mar 24, 2007 at 03:25:38PM -0700, Zachary Pincus wrote: > If Lena is converted to floating-point before the rotation is > applied, and then the intensity range is clipped to [0,255] and > converted back to uint8 before saving, everything looks fine. Thanks, Zachary! I can confirm that

Re: [Numpy-discussion] Detect subclass of ndarray

On Sat, 24 Mar 2007, Anne Archibald apparently wrote: > Note that taking a vector and left-multiplying it by > a matrix is a very natural operation that won't work any > more if you treat all vectors as if they were row vectors. Can you be more specific on this "naturalness"? What is the cost

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Travis Oliphant <[EMAIL PROTECTED]> wrote: Alan G Isaac wrote: > On Sat, 24 Mar 2007, Travis Oliphant apparently wrote: > >> My opinion is that a 1-d array in matrix-multiplication >> should always be interpreted as a row vector. Is this not >> what is currently done? If not, then

Re: [Numpy-discussion] nd_image.affine_transform edge effects

Hello all, Mystery solved, I think. I downloaded Stéfan's Lena images and tried rotating them myself. As far as I can tell, the artifacts are caused by numerical overflow, as Lena is an unsigned 8-bit image. If Lena is converted to floating-point before the rotation is applied, and then th

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On 3/25/07, Robert Kern <[EMAIL PROTECTED]> wrote: > Bill Baxter wrote: > I don't know. Given our previous history with convenience functions with > different calling semantics (anyone remember rand()?), I think it probably > will > confuse some people. > > I'd really like to see it on a cookbook

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On 3/25/07, Robert Kern <[EMAIL PROTECTED]> wrote: > Bill Baxter wrote: > > > I think it's fine for filter()/reduce()/map() to be taken out of > > builtins and moved to a standard module, but it's not clear that > > that's what they're going to do. That py3K web page just says "remove > > reduce()

Re: [Numpy-discussion] New Operators in Python

On 24/03/07, Charles R Harris <[EMAIL PROTECTED]> wrote: > Yes indeed, this is an old complaint. Just having an infix operator would be > an improvement: > > A dot B dot C > > Not that I am suggesting dot in this regard ;) In particular, it wouldn't > parse without spaces. What about division? Mat

Re: [Numpy-discussion] New Operators in Python

On 3/24/07, Charles R Harris <[EMAIL PROTECTED]> wrote: > > > On 3/24/07, Travis Oliphant <[EMAIL PROTECTED]> wrote: > > Every so often the idea of new operators comes up because of the need to > > do both "matrix-multiplication" and element-by-element multiplication. > > > > I think this is one ar

Re: [Numpy-discussion] nd_image.affine_transform edge effects

On Sat, Mar 24, 2007 at 01:41:21AM -0400, James Turner wrote: > That's hard to say. Just because it's mainly a continuous-tone image > doesn't necessarily mean it is well sampled everywhere. This depends > both on the subject and the camera optics. Unlike the data I usually > work with, I think eve

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

Bill Baxter wrote: > I think it's fine for filter()/reduce()/map() to be taken out of > builtins and moved to a standard module, but it's not clear that > that's what they're going to do. That py3K web page just says "remove > reduce()... done". http://svn.python.org/projects/python/branches/p3y

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On 3/25/07, Alan G Isaac <[EMAIL PROTECTED]> wrote: > On Sun, 25 Mar 2007, Bill Baxter apparently wrote: > > So if one just > > changes the example to > > reduce(lambda s, a: s * a.myattr, data, 1) > > How does one write that in a simplified way using generator > > expressions without calling on

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

Bill Baxter wrote: > On 3/24/07, Anne Archibald <[EMAIL PROTECTED]> wrote: >> You could do this, and for your >> own code maybe it's worth it, but I think it would be confusing in the >> library. > > Could be. Doesn't seem so confusing to me as long as it's documented > clearly in the docstring,

Re: [Numpy-discussion] New Operators in Python

On 3/24/07, Travis Oliphant <[EMAIL PROTECTED]> wrote: Every so often the idea of new operators comes up because of the need to do both "matrix-multiplication" and element-by-element multiplication. I think this is one area where the current Python approach is not as nice because we have a limi

Re: [Numpy-discussion] New Operators in Python

Hi, I followed the discussion on the scipy ML, and I would advocate it as well. I miss the dichotomy that is present in Matlab, and to have a similar degree of freedom, it would be good to have it in the upcoming major release of Python. Matthieu 2007/3/24, Travis Oliphant <[EMAIL PROTECTED]>:

Re: [Numpy-discussion] Detect subclass of ndarray

On 24/03/07, Travis Oliphant <[EMAIL PROTECTED]> wrote: > My opinion is that a 1-d array in matrix-multiplication should always be > interpreted as a row vector. Is this not what is currently done? If > not, then it is a bug in my mind. An alternative approach, in line with the usual usage, is

Re: [Numpy-discussion] Detect subclass of ndarray

On Sat, 24 Mar 2007, Travis Oliphant apparently wrote: > I'd be fine with an error raised on matrix multiplication > (as long as dot is not changed). In other words, I'd > like to see 1-d arrays always interpreted the same way (as > row vectors) when used in matrix multiplication. My prefer

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Travis Oliphant <[EMAIL PROTECTED]> wrote: Alan G Isaac wrote: > On Sat, 24 Mar 2007, Travis Oliphant apparently wrote: > >> My opinion is that a 1-d array in matrix-multiplication >> should always be interpreted as a row vector. Is this not >> what is currently done? If not, then

Re: [Numpy-discussion] Detect subclass of ndarray

Alan G Isaac wrote: > On Sat, 24 Mar 2007, Travis Oliphant apparently wrote: > >> My opinion is that a 1-d array in matrix-multiplication >> should always be interpreted as a row vector. Is this not >> what is currently done? If not, then it is a bug in my >> mind. >> > > N.

Re: [Numpy-discussion] Detect subclass of ndarray

Charles R Harris wrote: > > > On 3/24/07, *Travis Oliphant* <[EMAIL PROTECTED] > > wrote: > > Alan G Isaac wrote: > > On Sat, 24 Mar 2007, Charles R Harris apparently wrote: > > > >> Yes, that is what I am thinking. Given that there are only the two >

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Travis Oliphant <[EMAIL PROTECTED]> wrote: Alan G Isaac wrote: > On Sat, 24 Mar 2007, Charles R Harris apparently wrote: > >> Yes, that is what I am thinking. Given that there are only the two >> possibilities, row or column, choose the only one that is compatible with >> the multipl

Re: [Numpy-discussion] Detect subclass of ndarray

On Sat, 24 Mar 2007, Travis Oliphant apparently wrote: > My opinion is that a 1-d array in matrix-multiplication > should always be interpreted as a row vector. Is this not > what is currently done? If not, then it is a bug in my > mind. >>> N.__version__ '1.0' >>> I matrix([[ 1., 0.],

Re: [Numpy-discussion] nd_image.affine_transform edge effects

Hello folks, >> Hmm, this is worrisome. There really shouldn't be ringing on >> continuous-tone images like Lena -- right? (And at no step in an >> image like that should gaussian filtering be necessary if you're >> doing spline interpolation -- also right?) > > That's hard to say. Just because i

Re: [Numpy-discussion] Detect subclass of ndarray

Alan G Isaac wrote: > On Sat, 24 Mar 2007, Charles R Harris apparently wrote: > >> Yes, that is what I am thinking. Given that there are only the two >> possibilities, row or column, choose the only one that is compatible with >> the multiplying matrix. The result will not always be a column

[Numpy-discussion] New Operators in Python

Every so often the idea of new operators comes up because of the need to do both "matrix-multiplication" and element-by-element multiplication. I think this is one area where the current Python approach is not as nice because we have a limited set of operators to work with. One thing I wonder i

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On 3/25/07, Steven H. Rogers <[EMAIL PROTECTED]> wrote: > The generator expression PEP doesn't say this, but the Python 3000 > planning PEP (http://www.python.org/dev/peps/pep-3100/) has map() and > filter() on the 'to-be-removed' list with a parenthetic comment that > they can stay. Removal of re

Re: [Numpy-discussion] Detect subclass of ndarray

On Sat, 24 Mar 2007, Charles R Harris apparently wrote: > Yes, that is what I am thinking. Given that there are only the two > possibilities, row or column, choose the only one that is compatible with > the multiplying matrix. The result will not always be a column vector, for > instance, mat([

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On Sun, 25 Mar 2007, Bill Baxter apparently wrote: > So if one just > changes the example to > reduce(lambda s, a: s * a.myattr, data, 1) > How does one write that in a simplified way using generator > expressions without calling on reduce? Eliminating the expressiveness of ``reduce`` has

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

Perry Greenfield wrote: > On Mar 24, 2007, at 2:52 PM, Bill Baxter wrote: > >> On 3/24/07, Steven H. Rogers <[EMAIL PROTECTED]> wrote: >>> Anne Archibald wrote: P.S. reduce isn't even a numpy thing, it's one of python's much-neglected lispy functions. >>> It looks like reduce(), map

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On 3/25/07, Perry Greenfield <[EMAIL PROTECTED]> wrote: > > On Mar 24, 2007, at 2:52 PM, Bill Baxter wrote: > > > On 3/24/07, Steven H. Rogers <[EMAIL PROTECTED]> wrote: > >> Anne Archibald wrote: > >>> > >>> P.S. reduce isn't even a numpy thing, it's one of python's > >>> much-neglected lispy func

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Colin J. Williams <[EMAIL PROTECTED]> wrote: Charles R Harris wrote: > > > On 3/24/07, *Alan G Isaac* <[EMAIL PROTECTED] > > wrote: > > On Fri, 23 Mar 2007, Charles R Harris apparently wrote: > > the following gives the wrong result: > > In [15

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On 3/24/07, Anne Archibald <[EMAIL PROTECTED]> wrote: > On 24/03/07, Bill Baxter <[EMAIL PROTECTED]> wrote: > > > Nice, but how does that fare on things like mdot(a,(b,c),d) ? I'm > > pretty sure it doesn't handle it. > > I think an mdot that can only multiply things left to right comes up > > sho

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On Mar 24, 2007, at 2:52 PM, Bill Baxter wrote: > On 3/24/07, Steven H. Rogers <[EMAIL PROTECTED]> wrote: >> Anne Archibald wrote: >>> >>> P.S. reduce isn't even a numpy thing, it's one of python's >>> much-neglected lispy functions. >>> >> >> It looks like reduce(), map(), and filter() are going

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On 3/24/07, Steven H. Rogers <[EMAIL PROTECTED]> wrote: > Anne Archibald wrote: > > > > P.S. reduce isn't even a numpy thing, it's one of python's > > much-neglected lispy functions. > > > > It looks like reduce(), map(), and filter() are going away for Python > 3.0 since GvR believes that they are

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

Bill Baxter wrote: > On 3/24/07, Anne Archibald <[EMAIL PROTECTED]> wrote: >> On 24/03/07, Bill Baxter <[EMAIL PROTECTED]> wrote: >>> I mentioned in another thread Travis started on the scipy list that I >>> would find it useful if there were a function like dot() that could >>> multiply more than

Re: [Numpy-discussion] Detect subclass of ndarray

Charles R Harris wrote: > > > On 3/24/07, *Alan G Isaac* <[EMAIL PROTECTED] > > wrote: > > On Fri, 23 Mar 2007, Charles R Harris apparently wrote: > > the following gives the wrong result: > > In [15]: I = matrix(eye(2)) > > In [16]: I*ones(2) >

Re: [Numpy-discussion] swig svn commits

On 3/24/07, Bill Spotz <[EMAIL PROTECTED]> wrote: > No, I don't consider native byte order. What was your solution? > I think there is only one solution: If somebody requests INPLACE handling but provides data of wrong byteorder, I have to throw an exception -- in SWIG terms, the typecheck return

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Alan G Isaac <[EMAIL PROTECTED]> wrote: On Sat, 24 Mar 2007, Charles R Harris apparently wrote: > I think it is reasonable to raise an exception in this > case, but that is not how numpy currently works, so it is > a larger policy decision that I can't make on my own. For > the case

Re: [Numpy-discussion] Detect subclass of ndarray

On Sat, 24 Mar 2007, Charles R Harris apparently wrote: > I think it is reasonable to raise an exception in this > case, but that is not how numpy currently works, so it is > a larger policy decision that I can't make on my own. For > the case under consideration it is possible to define 1-D >

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Alan G Isaac <[EMAIL PROTECTED]> wrote: >> On Fri, 23 Mar 2007, Charles R Harris apparently wrote: >>> the following gives the wrong result: >>> In [15]: I = matrix(eye(2)) >>> In [16]: I*ones(2) >>> Out[16]: matrix([[ 1., 1.]]) >>> where the output should be a column vector. > On

Re: [Numpy-discussion] Detect subclass of ndarray

>> On Fri, 23 Mar 2007, Charles R Harris apparently wrote: >>> the following gives the wrong result: >>> In [15]: I = matrix(eye(2)) >>> In [16]: I*ones(2) >>> Out[16]: matrix([[ 1., 1.]]) >>> where the output should be a column vector. > On 3/24/07, Alan G Isaac <[EMAIL PROTECTED]> wrote:

Re: [Numpy-discussion] swig svn commits

No, I don't consider native byte order. What was your solution? The typecheck typemap is so that swig can perform isolated type checking when it is creating dispatch code for overloaded functions. The typechecks I added for INPLACE arrays require that the argument be a numpy array and that

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Alan G Isaac <[EMAIL PROTECTED]> wrote: On Fri, 23 Mar 2007, Charles R Harris apparently wrote: > the following gives the wrong result: > In [15]: I = matrix(eye(2)) > In [16]: I*ones(2) > Out[16]: matrix([[ 1., 1.]]) > where the output should be a column vector. Why should this ou

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

Alan G Isaac wrote: > On Sat, 24 Mar 2007, "Steven H. Rogers" apparently wrote: >> It looks like reduce(), map(), and filter() are going away for Python >> 3.0 since GvR believes that they are redundant and list comprehensions >> and generator expressions are more readable alternatives. lambda

Re: [Numpy-discussion] Detect subclass of ndarray

On Fri, 23 Mar 2007, Charles R Harris apparently wrote: > the following gives the wrong result: > In [15]: I = matrix(eye(2)) > In [16]: I*ones(2) > Out[16]: matrix([[ 1., 1.]]) > where the output should be a column vector. Why should this output a column? I would prefer an exception. Add the ax

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On Sat, 24 Mar 2007, "Steven H. Rogers" apparently wrote: > It looks like reduce(), map(), and filter() are going away for Python > 3.0 since GvR believes that they are redundant and list comprehensions > and generator expressions are more readable alternatives. lambda was on > the block as we

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

Anne Archibald wrote: > > P.S. reduce isn't even a numpy thing, it's one of python's > much-neglected lispy functions. > It looks like reduce(), map(), and filter() are going away for Python 3.0 since GvR believes that they are redundant and list comprehensions and generator expressions are mor

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

but how about the things like a = dot(array([8]), ones([1000,1000], array([15])))? it will be much faster if we will dot 8 x 15 at first, and than the result to the big array. D. Anne Archibald wrote: > On 24/03/07, Bill Baxter <[EMAIL PROTECTED]> wrote: > > >> Nice, but how does that fare on

Re: [Numpy-discussion] Simple multi-arg wrapper for dot()

On 24/03/07, Bill Baxter <[EMAIL PROTECTED]> wrote: > Nice, but how does that fare on things like mdot(a,(b,c),d) ? I'm > pretty sure it doesn't handle it. > I think an mdot that can only multiply things left to right comes up > short compared to an infix operator that can easily use parentheses

Re: [Numpy-discussion] Detect subclass of ndarray

On 3/24/07, Charles R Harris <[EMAIL PROTECTED]> wrote: > > > On 3/23/07, Anne Archibald <[EMAIL PROTECTED]> wrote: > > On 23/03/07, Charles R Harris <[EMAIL PROTECTED]> wrote: > > > Anyone, > > > > > > What is the easiest way to detect in python/C if an object is a subclass > of > > > ndarray? > >