( Re Message From: tarcisio praciano pereira )

>

> Why the octave does'nt understand my gplot - line 9 ? How could I

> define

> expression so it can gnuplot-display graphics?

>

>

> ***********begining of file interf.data ***********************

> # data-sheet for Octave, does'nt work for Gnuplot

> # set term latex; set output 'interf.tex'

> set title 'graficos de funcoes'

> set xrange [-10:10]; set yrange [0:3]

> function y = A (x) 1/(1+((x-4)/5)**2) endfunction

> function y = B (x) 1/(1+((x+4)/5)**2) endfunction

> function y = C (x) 1/(1+(x/5)**2) + 0.1*sin(2*x) endfunction

> # x = (-11:11)

> gplot -11:11 -20:20 A(x),B(x),C(x) using points;

> # gplot y=A(x),y=B(x),y=C(x) using points;

> #A(4)

> #B(-4)

> #C(0)

> # pause -1

It would take too long to explain everything that is wrong with the above

as an octave file. Basically, however, there are only a few "pure" gnuplot

commands that you can write in octave, to be passed straight through to

gnuplot. Gnuplot syntax mostly causes errors in octave, and a gnuplot data

file simply will not work as an octave file (with a few very simple

exceptions).

The following (in a form as near to gnuplot syntax as I can get it)

should work:

function y = A (x); y=1./(1+((x-4)/5).^2); endfunction

function y = B (x); y=1./(1+((x+4)/5).^2); endfunction

function y = C (x); y=1./(1+(x/5).^2) + 0.1*sin(2*x); endfunction

x = (-11:11);

gset title 'graficos de funcoes'

gset xrange [-10:10]; gset yrange [0:3]

gset data style points

plot( x,A(x), x,B(x), x,C(x) );

Please note EVERY difference between the above and your original: each

difference prevents an octave error, warning, or unwanted behaviour.

I hope this helps.

Ted. (

[hidden email])