From help-request at octave dot org Tue Nov 22 19:54:21 2005
Subject: Re: Question about Range class
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: "Robert A. Macy" <macy at california dot com>
Cc: Marek Szczypinski <markacy at astri dot uni dot torun dot pl>, help@octave.org
Date: Tue, 22 Nov 2005 20:28:53 -0500

On 22-Nov-2005, Robert A. Macy wrote:

| >From a newbie and untested...
| 
| double z[100];
| 
| for (int i = 0; i < 100; i++)
|   z[i] = 0.1 + ( static_cast<double>(i) )/10.0;

Octave has a Range class for this kind of operation, so you don't have
to do it by hand.  Note that your code assumes you know precisely how
many elements are in the range.  If someone just hands you the base,
limit, and increment for the range, are you sure you could calculate
the best approximation of the number of elements?  Do you think it is
a simple calculation?  You might be surprised by the answer (take a
look at the code that does this in src/Range.cc)!

|  Marek Szczypinski <markacy at astri dot uni dot torun dot pl> wrote:
| > Hello,
| > how should I write
| > z = [ 0 : 0.1 : 10 ] in c++?
| > thanks,
| > marek

For 0:0.1:10, try

  Range r (0.0, 10.0, 0.1);  // base, limit, increment

In Octave, if you write

  [0:0.1:10]

the result is actually a Matrix object, so you would need to write

  Range r (0.0, 10.0, 0.1);  // base, limit, increment
  Matrix m = r.matrix_value ();

jwe



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