Re: [Maxima-discuss] Stair function

[Pierre C. <pie...@ac...>]

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.

Regards,

Pierre


Le 06/04/2024 à 17:59, Jaime Villate a écrit :
> Try this:
>
> g(x):=E(f,x,10,0,1)$
>
> plot2d([f,g], [x,0,1]);
>
> Plot2d expects an expression of one variable or the name of a function 
> with only input parameter. Notice that neither E(f,x,10,0,1)]  nor 
> g(x) return an expression with the variable x and E is not the name of 
> a function with a single input parameter but g is.
>
> Regards,
>
> Jaime
>
> On 06/04/24 16:32, Pierre CAMPET wrote:
>>
>> Hello
>>
>>
>> I'd like to draw a stair function to illustrate what we called in 
>> france "Méthode des rectangles" :
>>
>> I try this :
>>
>> f(x):=1/(1+x);
>> E(f,x,n,a,b):=block(
>>     if x=b then return(f(b))
>>     else
>>     for i:1 thru n do if (x < a+i*(b-a)/n) then return(f(a+(i-1)/n))
>> );
>> E(f,0.19,10,0,1);
>> E(f,1,10,0,1);
>> E(f,0,10,0,1);
>>
>> But
>>
>> wxplot2d([f(x),E(f,x,10,0,1)], [x,0,1])$
>>
>> give me an error : COERCE-FLOAT-FUN: no such Lisp or Maxima function: 
>> done
>>
>> any idea to produce the function may be with no evaluation on each x ?
>>
>>