Re: [Maxima-discuss] Stair function

[Robert D. <rob...@gm...>]

On Sat, Apr 6, 2024 at 9:46 AM Pierre CAMPET <pie...@ac...> wrote:
>
> Thanks for the help
>
> when i try your solution i get
>
> plot2d: expression g
>     should  depend only on x, or be an expression of 2 variables
>
> the values of g(0), g(0.19) and g(1) are correct.

Pierre, thanks for your interest in Maxima. I'm not entirely certain,
but I believe the behavior you observe is the consequence of a subtle
distinction between "=" and "equal" in Maxima. Try changing the first
condition in your function E from

  if x = b then ...

to

  if equal(x, b) then ...

Do you get the expected plot with that change?

There are other ways to represent the stair step function. Here is a
different formulation --

  E(f, x, n, a, b) := if x < a or x > b then 0 else block([d, k], d:
(b - a)/n, k: floor((x - a)/d), f(k*d));

and then as before with

  g(x) := E(f, x, 10, 0, 1);

I find that

  plot2d ([f, g], [x, 0, 1]);

shows the expected plot. Does that work for you?

best

Robert