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Re: Help-octave Digest, Vol 30, Issue 65


From: bharat pathak
Subject: Re: Help-octave Digest, Vol 30, Issue 65
Date: Thu, 25 Sep 2008 11:11:21 +0530

Russell,

  you will not be able to do that. essentially this kind of syntax helps in
  deleting row and col of any matrix.

  a = rand(2,2)

  a(:,2) = []     % will delete all rows and second column of 2d matrix a

   hence if you say

a = [] % means it will delete all entries in matrix even if it existed a-priori.

Regards
Bharat Pathak

Arithos Designs
www.Arithos.com



--------------------------------------------------
From: "Russell jarvis" <address@hidden>
Sent: Thursday, September 25, 2008 10:49 AM
To: <address@hidden>
Subject: Re: Help-octave Digest, Vol 30, Issue 65

I wonder if any can tell me how to declare an empty multidimensional
array or matrix.

I declare a blank 1 dimensional array:

array1 = [];

but I want to do something like:

array2=[][];

Thanks for any help.

Russell.

On Thu, Sep 25, 2008 at 3:03 AM,  <address@hidden> wrote:
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Today's Topics:

  1. Re: Fwd: Gaussian fit of a peak (LUK ShunTim)
  2. Re: Gaussian fit of a peak (Rob Mahurin)
  3. Re: strange regexp behavior (John W. Eaton)
  4. Returned value from function as a global variable (LUK ShunTim)


----------------------------------------------------------------------

Message: 1
Date: Wed, 24 Sep 2008 18:08:21 +0800
From: LUK ShunTim <address@hidden>
Subject: Re: Fwd: Gaussian fit of a peak
To: Andrea Cimatoribus <address@hidden>
Cc: address@hidden
Message-ID: <address@hidden>
Content-Type: text/plain; charset=UTF-8

Andrea Cimatoribus wrote:
Here is what Octave says:

octave-3.0.0:3> pkg install miscellaneous-1.0.7.tar.gz
configure: WARNING: no mkoctfile found on path

You need to install the octave3.0-headers debian/ubuntu package (which
provides mkoctfile etc) to install most octave-forge packages.

Regards,
ST
--


------------------------------

Message: 2
Date: Wed, 24 Sep 2008 11:26:23 -0400
From: Rob Mahurin <address@hidden>
Subject: Re: Gaussian fit of a peak
To: "Andrea Cimatoribus" <address@hidden>
Cc: address@hidden
Message-ID: <address@hidden>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

On Sep 24, 2008, at 4:04 AM, Andrea Cimatoribus wrote:
Unfortunately, I am not sure I will be able to keep "central" area
only, since I am fitting something that resembles a phonon spectra.
In fact, I have multiple peakes to the left and right with respect
to the "zero", but fitting everything with a gaussian balanced to
the zero energy pretty well. I need to do this in order to sum
spectra together. I will let you know if and how I solve this
problem if it is of any intereset.
AC

The leasqr wrapper I mentioned can handle multiple overlapping
Gaussians.  You might wonder, for instance, whether a fit to two
unresolved peaks gives a smaller chi-squared per degree of freedom
than a fit to a single peak.  This is what the "demo" does for a
dodgy problem with two exponentials.  (Though you have to find the
chi2 yourself, sum( ((y-f5)./errscale).^2 ), after the demo runs,
because I wasn't thinking of this when I wrote it).

If you have some constant background you'll have to subtract it by
hand for now.

code, again, at
       http://sns.phys.utk.edu/~mahurin/octave/

Cheers,
Rob

--
Rob Mahurin
Dept. of Physics & Astronomy
University of Tennessee         phone: 865 207 2594
Knoxville, TN 37996             email: address@hidden



------------------------------

Message: 3
Date: Wed, 24 Sep 2008 11:40:21 -0400
From: "John W. Eaton" <address@hidden>
Subject: Re: strange regexp behavior
To: David Bateman <address@hidden>
Cc: address@hidden, "G.." <address@hidden>
Message-ID: <address@hidden>
Content-Type: text/plain; charset=us-ascii

On 23-Sep-2008, David Bateman wrote:

| Ok, then what about the attached changeset for 3.1.51+ based on your
| patch that
|
| * Adds a call to OCTAVE_QUIT
| * Adds the loop counter to terminate for truly infinitely recursive patterns
| * Adds a test based on the previously failing code.
|
| I compiled and tested this sucessfully with 3.1.51+ and suppose it will
| work for 3.0.2+ as well.

I applied it.

Thanks,

jwe


------------------------------

Message: 4
Date: Thu, 25 Sep 2008 00:20:13 +0800
From: LUK ShunTim <address@hidden>
Subject: Returned value from function as a global variable
To: address@hidden
Message-ID: <address@hidden>
Content-Type: text/plain; charset=ISO-8859-1

Hi,

I had some matlab code which uses global variables to allow common
access to returned values from functions. It appears that octave doesn't
allow such behaviour. Here's a short function which produces an error in
octave.

function [v]=t_global_f(x)
   global v;
   v = sin(x);
endfunction

octave:1> x=0:0.1:pi;
octave:2> v=t_global_f(x);
error: can't make function parameter `v' global
error: evaluating global command near line 6, column 1
error: called from `t_global_f' in file
`/home/0/00work/octave/00snippets/t_global_f.m'
error: evaluating assignment expression near line 2, column 2

Is there any plan to implement the same behaviour in octave?

Regards,
ST
--



------------------------------

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