Re: "table too short" error while trying to plot a function

[Martin Helm]

Am Freitag, 14. Mai 2010 02:21:31 schrieb Leo Arias F.:
> Hello,
> 
> I'm new with this. I'm just learning with the matlab guide.
> 
> I followed the guide in [1] and could plot the humps funtion without
> problems.
> 
> But I defined my own function on the functiontest1.m file:
>   function y = functiontest1(x)
>   if abs(x)<1
>     y = 1;
>   elseif 1 < abs(x) && abs(x) < 2
>     y = 2 - abs(x);
>   else
>     y = 0;
>   end
> 
> And when I try to plot it:
> octave3.2:1> fplot(@functiontest1, [-3 3])
> 
> I get the following error:
> error: interp1: table too short
> error: called from:
> error:   /usr/share/octave/3.2.3/m/general/interp1.m at line 143, column 5
> error:   /usr/share/octave/3.2.3/m/plot/fplot.m at line 86, column 11
> 
> Could you please tell me what I'm doing wrong?
> 
> thanks :)
> pura vida
> 
> [1]
> http://www.mathworks.com/access/helpdesk/help/techdoc/math/bsgprpq-4.html
> 

You will need to write your function in a vectorized form not in this scalar 
form, for example something like

function y = functiontest1(x)
  y=zeros(size(x));
  i1 = abs(x)<1;
  i2 = 1 < abs(x) & abs(x) < 2;
  y(i1) = 1;
  y(i2) = 2-abs(x(i2));
endfunction

Then it will work.

- mh