Re: function values vector

[Francesco Potortì]

>I have a vector x=linspace(0,2*pi,256). There is a function H given as
>follows:
>
>function y=H(x)
>    if (x<pi)
>        y=0;
>    else 
>        y=1;
>    endif
>end
>
>Now, I want a vector Y such that each of its coordinates xi is H(xi).

The esiest is to do this:

octave> x=linspace(0,2*pi,16)
x =

 Columns 1 through 8:
   0.00000   0.41888   0.83776   1.25664   1.67552   2.09440   2.51327   2.93215
 Columns 9 through 16:
   3.35103   3.76991   4.18879   4.60767   5.02655   5.44543   5.86431   6.28319

octave> Y = (x >= pi)
Y =

   0   0   0   0   0   0   0   0   1   1   1   1   1   1   1   1

However, these are not really zeros and ones, but boolean values:

octave> typeinfo (Y)
ans = bool matrix

This is not normally a problem, on the contrary, it is usually what you
want and takes less memory space.  Moreover, if you perform math
operations on them, they are converted to numbers. Anyway, if for some
reason you need real zeros and ones you can use double():

octave> typeinfo(double(Y))
ans = matrix

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