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

[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

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