Re: [Numpy-discussion] Silent Broadcasting considered harmful

2015-02-08 Thread Warren Focke
On Sun, 8 Feb 2015, Stefan Reiterer wrote: And as already mentioned: other matrix languages also allow it, but they warn about it's usage. This has indeed it's merits. numpy isn't a matrix language. They're arrays. Storing numbers that you are thinking of as a vector in an array doesn't

Re: [Numpy-discussion] numpy.fft.irfftn fails apparently unexpectedly

2012-02-07 Thread Warren Focke
coefficients it means complex), though I've not read any of the Python code. You're not doing anything wrong. irfftn takes complex input and returns real output. The exception is a bug which is triggered because max(axes) = len(axes). Warren Focke

Re: [Numpy-discussion] numpy.fft.irfftn fails apparently unexpectedly

2012-02-07 Thread Warren Focke
On Tue, 7 Feb 2012, Henry Gomersall wrote: On Tue, 2012-02-07 at 11:53 -0800, Warren Focke wrote: You're not doing anything wrong. irfftn takes complex input and returns real output. The exception is a bug which is triggered because max(axes) = len(axes). Is this a bug I should register

Re: [Numpy-discussion] numpy.fft.irfftn fails apparently unexpectedly

2012-02-07 Thread Warren Focke
On Tue, 7 Feb 2012, Henry Gomersall wrote: On Tue, 2012-02-07 at 12:26 -0800, Warren Focke wrote: Is this a bug I should register? Yes. It should work right if you replace s[axes[-1]] = (s[axes[-1]] - 1) * 2 with s[-1] = (a.shape[axes[-1]] - 1) * 2 but I'm not really

Re: [Numpy-discussion] matrix inversion

2011-08-10 Thread Warren Focke
The svs are 1.1695e-01, 1.1682e-01, 6.84719250e-10 so if you try np.linalg.pinv(a,1e-5) array([[ 0.41097834, 3.12024106, -3.26279309], [-3.38526587, 0.30274957, 1.89394811], [ 2.98692033, -2.30459609, 0.28627222]]) you at least get an answer that's not

Re: [Numpy-discussion] how to multiply the rows of a matrix by a different number?

2009-03-03 Thread Warren Focke
M *= N[:, newaxis] On Tue, 3 Mar 2009, Jose Borreguero wrote: I guess there has to be an easy way for this. I have: M.shape=(1,3) N.shape=(1,) I want to do this: for i in range(1): M[i]*=N[i] without the explicit loop -Jose ___

Re: [Numpy-discussion] Floating Point Difference between numpy and numarray

2008-09-09 Thread Warren Focke
On Tue, 9 Sep 2008, David Cournapeau wrote: We don't use SSE and co in numpy, and I doubt the compilers (even Intel one) are able to generate effective SSE for numpy ATM. Actually, double and float are about the same speed for x86 (using the x87 FPU and not the SSE units), because

Re: [Numpy-discussion] Log Arrays

2008-05-08 Thread Warren Focke
On Thu, 8 May 2008, Charles R Harris wrote: On Thu, May 8, 2008 at 10:11 AM, Anne Archibald [EMAIL PROTECTED] wrote: 2008/5/8 Charles R Harris [EMAIL PROTECTED]: What realistic probability is in the range exp(-1000) ? Well, I ran into it while doing a maximum-likelihood fit - my early

Re: [Numpy-discussion] Log Arrays

2008-05-08 Thread Warren Focke
On Thu, 8 May 2008, Charles R Harris wrote: On Thu, May 8, 2008 at 11:46 AM, Anne Archibald [EMAIL PROTECTED] wrote: 2008/5/8 Charles R Harris [EMAIL PROTECTED]: On Thu, May 8, 2008 at 10:56 AM, Robert Kern [EMAIL PROTECTED] wrote: When you're running an optimizer over a PDF, you will

Re: [Numpy-discussion] finding eigenvectors etc

2008-02-20 Thread Warren Focke
The vectors that you used to build your covariance matrix all lay in or close to a 3-dimensional subspace of the 4-dimensional space in which they were represented. So one of the eigenvalues of the covariance matrix is 0, or close to it; the matrix is singular. Condition is the ratio of the

Re: [Numpy-discussion] finding eigenvectors etc

2008-02-19 Thread Warren Focke
Yes. Your first eigenvalue is effectively 0, the values you see are just noise. Different implementations produce different noise. As for the signs ot the eigenvector components, which direction is + or - X is arbitrary. Different implementations follow different conventions as to which is

Re: [Numpy-discussion] array allocation using tuples gives views of same array

2007-11-15 Thread Warren Focke
On Thu, 15 Nov 2007, George Nurser wrote: It looks to me like a,b = (zeros((2,)),)*2 is equivalent to x= zeros((2,)) a,b=(x,)*2 Correct. If this is indeed a feature rather than a bug, is there an alternative compact way to allocate many arrays? a, b = [zeros((2,)) for x in range(2)]

Re: [Numpy-discussion] C or C++ package like NumPy?

2007-11-01 Thread Warren Focke
http://www.oonumerics.org/blitz/ On Fri, 2 Nov 2007, Bill Baxter wrote: Does anyone know of a C or C++ library that's similar to NumPy? Seems like all the big C++ efforts are focused on linear algebra rather than general purpose multidimensional arrays. I've written a multidimensional array

Re: [Numpy-discussion] comparing arrays with NaN in them.

2007-08-23 Thread Warren Focke
On Thu, 23 Aug 2007, Christopher Barker wrote: but that feels like a kludge. maybe some sort of TheseArrays are binary equal would be useful. But there are multiple possible NaNs, so you couldn't rely on the bits comparing. Maybe something with masked arrays? w

Re: [Numpy-discussion] fourier with single precision

2007-08-02 Thread Warren Focke
On Thu, 2 Aug 2007, Lars Friedrich wrote: What I understood is that numpy uses FFTPACK's algorithms. Sort of. It appears to be a hand translation from F77 to C. From www.netlib.org/fftpack (is this the right address?) I took that there is a single-precision and double-precision-version

Re: [Numpy-discussion] fourier with single precision

2007-08-02 Thread Warren Focke
On Thu, 2 Aug 2007, Charles R Harris wrote: On X86 machines the main virtue would be smaller and more cache friendly arrays because double precision arithmetic is about the same speed as single precision, sometimes even a bit faster. The PPC architecture does have faster single than double

Re: [Numpy-discussion] annoying numpy string to float conversion behaviour

2007-06-25 Thread Warren Focke
On Mon, 25 Jun 2007, Torgil Svensson wrote: handled with sub-classing. At a minimum float(str(nan))==nan should evaluate as True. False. No NaN should ever compare equal to anything, even itself. But if the system is 754-compliant, it won't. isnan(float(str(nan))) == True would be nice,

Re: [Numpy-discussion] Oddity with numpy.int64 integer division

2007-04-25 Thread Warren Focke
On futher contemplation, and hearing others' arguments, I'm changing my vote. Make it compatible with python. w On Tue, 24 Apr 2007, Warren Focke wrote: On Tue, 24 Apr 2007, Timothy Hochberg wrote: On 4/24/07, Robert Kern [EMAIL PROTECTED] wrote: Christian Marquardt wrote

Re: [Numpy-discussion] Oddity with numpy.int64 integer division

2007-04-24 Thread Warren Focke
On Tue, 24 Apr 2007, Timothy Hochberg wrote: On 4/24/07, Robert Kern [EMAIL PROTECTED] wrote: Christian Marquardt wrote: Restore the invariant, and follow python. This seems to imply that once upon a time numpy/numeric/numarray followed python here, but as far as I can recall

Re: [Numpy-discussion] Oddity with numpy.int64 integer division

2007-04-23 Thread Warren Focke
But even C89 required that x == (x/y)*y + (x%y), and that's not the case here. w On Mon, 23 Apr 2007, David M. Cooke wrote: On Apr 23, 2007, at 16:41 , Christian Marquardt wrote: On Mon, April 23, 2007 22:29, Christian Marquardt wrote: Actually, it happens for normal integers as well:

Re: [Numpy-discussion] zoom FFT with numpy?

2007-03-15 Thread Warren Focke
On Wed, 14 Mar 2007, Charles R Harris wrote: On 3/14/07, Ray Schumacher [EMAIL PROTECTED] wrote: What I had been doing is a 2048 N full real_FFT with a Hann window, and further analyzing the side lobe/bin energy (via linear interp) to try to more precisely determine the f within the

Re: [Numpy-discussion] FFT definition

2007-02-05 Thread Warren Focke
The frequencies produced by the two recipies are not the same. But the DFT is periodic in both frequency and time. So whether you think that the number in bin in n/2 should correspond to frequency n/2 or -n/2, it's the same number. w On Mon, 5 Feb 2007, Hanno Klemm wrote: Hi there, I have

Re: [Numpy-discussion] FFT definition

2007-02-05 Thread Warren Focke
On Mon, 5 Feb 2007, Timothy Hochberg wrote: On 2/5/07, Hanno Klemm [EMAIL PROTECTED] wrote: [numpy.fft[ The packing of the result is standard: If A = fft(a, n), then A[0] contains the zero-frequency term, A[1:n/2+1] contains the positive-frequency terms, and A[n/2+1:]