From help-octave-request at bevo dot che dot wisc dot edu  Tue Feb 29 01:31:59 2000
Subject: RE: is the ps graph plot match what original instruction intend?
From: (Ted Harding) <Ted dot Harding at nessie dot mcc dot ac dot uk>
To: help-octave at bevo dot che dot wisc dot edu
Date: Tue, 29 Feb 2000 01:32:54 -0600 (CST)


On 29-Feb-00 eric wrote:
> Dear octave programers:
> 
>   In 1994 mailing list about sinc funtion, 
> if we use 
> sin([-0.01:.001:-.001  pi/2  .001:.001:.01])./([-0.01:.001:-.001  1 
> .001:.001:.01]) to simulate sin(x)/(x) -0.01<x<0.01, why when I plot it
> out, the horizontal scale is from 0 to 25?
> include ps file
> 
> need and thanks your help
> Eric
> fsshl at uaf dot edu

I can only assume that (if 'y' denotes the vector of values of the
function) you have plotted it using the equivalent of

  plot(y)

Since there are 21 points to be plotted, and you have not given any
information about the range of x-values, it will plot the y-values
at x-coordinates 1, 2, ... , 20, 21 and choose a "rounded-up" x-range
of 0:25 for the x-axis.

You should get the correct plot if you let x = 0.001*(-10:10) and
then plot with

  plot(x,y)

I hope this helps.
Ted.

--------------------------------------------------------------------
E-Mail: (Ted Harding) <Ted dot Harding at nessie dot mcc dot ac dot uk>
Date: 28-Feb-00                                       Time: 15:33:40
------------------------------ XFMail ------------------------------



-----------------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.che.wisc.edu/octave/octave.html
How to fund new projects:  http://www.che.wisc.edu/octave/funding.html
Subscription information:  http://www.che.wisc.edu/octave/archive.html
-----------------------------------------------------------------------