[Numpy-discussion] __eq__ method for recarray returns recarray

2009-07-03 Thread Dan Yamins
If I have two recarrays with the same len and column headers, the __eq__ method returns the rich comparison, which is great. E.g. In [20]: x = np.rec.fromrecords([(1,2,'dd',.3),(33,2,'y',2.2),(2,3,'a',21.4),(3,4,'b',33.2)],names=['A','B','C','D']) In [21]: y = np.rec.fromrecords([(1,2,'dd',.3),(

Re: [Numpy-discussion] Bug in the F distribution?

2009-07-03 Thread Alan Jackson
I've tried the same scheme using R and it seems to give the right answers > quantile( rf(1000,10,10), .99) 99% 4.84548 > quantile( rf(1000,11,10), .99) 99% 4.770002 > quantile( rf(1000,11,11), .99) 99% 4.465655 > quantile( rf(1000,10,11), .99) 99% 4.539423

[Numpy-discussion] Bug in the F distribution?

2009-07-03 Thread Alan Jackson
I either found a bug in the F distribution, or I'm really messed up. >From a table I find dfnum dfden F(P<.01) 10 10 4.85 11 10 4.78 11 11 4.46 10 11 4.54 So let's calculate the same quantities using numpy... import scipy.stats as stats import numpy as np I

Re: [Numpy-discussion] roots and high-order polynomial

2009-07-03 Thread Pauli Virtanen
On 2009-07-03, Charles R Harris wrote: > roots? The connection between polynomial coefficients and polynomial values > becomes somewhat vague when the polynomial degree becomes large, it is > numerically ill conditioned. In addition to switching to higher precision than machine precision, anothe

Re: [Numpy-discussion] roots and high-order polynomial

2009-07-03 Thread Dag Sverre Seljebotn
Fabrice Silva wrote: > Le vendredi 03 juillet 2009 à 11:52 +0200, Nils Wagner a écrit : >> You will need multiprecision arithmetic in that case. >> It's an ill-conditioned problem. > > I may have said that the solution are of the same order of magnitude, so > that the ratio between the lowest and

Re: [Numpy-discussion] roots and high-order polynomial

2009-07-03 Thread Charles R Harris
On Fri, Jul 3, 2009 at 3:48 AM, Fabrice Silva wrote: > Hello > Has anyone looked at the behaviour of the (polynomial) roots function > for high-order polynomials ? I have an application which internally > searches for the roots of a polynomial. It works nicely for order less > than 20, and then h

Re: [Numpy-discussion] roots and high-order polynomial

2009-07-03 Thread Fabrice Silva
Le vendredi 03 juillet 2009 à 14:43 +0200, Nils Wagner a écrit : > Just curious - Can you provide us with the coefficients of > your polynomial ? Working case : Polynomial.c = [ -1.34100085e+57 +0.e+00j -2.28806781e+55 +0.e+00j -4.34808480e+54 -3.27208577e+36j -2.44499178e+

Re: [Numpy-discussion] roots and high-order polynomial

2009-07-03 Thread Nils Wagner
On Fri, 03 Jul 2009 14:26:39 +0200 Fabrice Silva wrote: > Le vendredi 03 juillet 2009 à 11:52 +0200, Nils Wagner a >écrit : >> You will need multiprecision arithmetic in that case. >> It's an ill-conditioned problem. > > I may have said that the solution are of the same order >of magnitude, s

Re: [Numpy-discussion] roots and high-order polynomial

2009-07-03 Thread Fabrice Silva
Le vendredi 03 juillet 2009 à 11:52 +0200, Nils Wagner a écrit : > You will need multiprecision arithmetic in that case. > It's an ill-conditioned problem. I may have said that the solution are of the same order of magnitude, so that the ratio between the lowest and the highest absolute values of

Re: [Numpy-discussion] argwhere does not accept py list

2009-07-03 Thread Scott Sinclair
>2009/7/3 Sebastian Haase : > Hi, > should this not be accepted: N.argwhere([4,0,2,1,3]) > ? > instead I get > > Traceback (most recent call last): >  File "", line 1, in >  File "./numpy/core/numeric.py", line 510, in argwhere > AttributeError: 'list' object has no attribute 'nonzero' N

Re: [Numpy-discussion] roots and high-order polynomial

2009-07-03 Thread Nils Wagner
On Fri, 03 Jul 2009 11:48:45 +0200 Fabrice Silva wrote: > Hello > Has anyone looked at the behaviour of the (polynomial) >roots function > for high-order polynomials ? I have an application which >internally > searches for the roots of a polynomial. It works nicely >for order less > than 20,

[Numpy-discussion] roots and high-order polynomial

2009-07-03 Thread Fabrice Silva
Hello Has anyone looked at the behaviour of the (polynomial) roots function for high-order polynomials ? I have an application which internally searches for the roots of a polynomial. It works nicely for order less than 20, and then has an erratic behaviour for upper values... I looked into the so

[Numpy-discussion] argwhere does not accept py list

2009-07-03 Thread Sebastian Haase
Hi, should this not be accepted: >>> N.argwhere([4,0,2,1,3]) ? instead I get Traceback (most recent call last): File "", line 1, in File "./numpy/core/numeric.py", line 510, in argwhere AttributeError: 'list' object has no attribute 'nonzero' >>> N.argwhere(N.array([4,0,2,1,3])) [[0] [2] [3

Re: [Numpy-discussion] Using loadtxt to read in mixed data types

2009-07-03 Thread Neil Crighton
Pierre GM gmail.com> writes: > What about > 'formats':[eval(b) for b in event_format] > > Should it fail, try something like: > dtype([(x,eval(b)) for (x,b) in zip(event_fields, event_format)]) > > At least you force dtype to have the same nb of names & formats. > You could use data = np.ge

Re: [Numpy-discussion] ndarray from column data

2009-07-03 Thread Francesc Alted
A Thursday 02 July 2009 20:15:13 Dan Yamins escrigué: > > What's wrong with recarrays? In any case, if you need a true ndarray > > object > > you can always do: > > > > ndarr = recarr.view(np.ndarray) > > > > and you are done. > > I have a question about this though. The object "ndarr" will consi