help: euler() prg on home mode

[toml_12953]

(05-30-2017 02:36 PM)compsystems Wrote:  Hello, the next numerical code, I want to run it in HOME MODE.

The definition v(t) does not allow me to define it within the code, Why?

PHP Code:

EXPORT euler()
BEGIN
    local g,c,m,t;
    local vi,ti,vf,tf;
        local v;
    purge(g,c,m,t,vi,ti,vf,tf);
    g:=9.81; c:=12.5; m:=68.1;
    v(t):= 'vi+(g-(c/m)*vi)*(t-ti)';
    vi:=0;  ti:=0;
    //print();
    FOR tf FROM 0 TO 60 STEP 2 DO
        print(); // clear terminal view (output)
        vf:=v(tf);
        print("vi = "+vi);
        print("ti = "+ti);
        print("tf = "+tf);
        print("vf("+tf+") = "+vf);
        print("");
        vi:=vf;
        ti:=tf;
        wait();
    END;
    return "Done";
END; 


Source: NUMERICAL METHODS FOR ENGINEERS Steven C. Chapra & Raymond P. Canale

euler (all lowercase) is a CAS function so I renamed it to EULER. Also, I'm not sure about your function definition. The following program works:

Code:

g;c;m;t;
vi;ti;vf;tf;

v(t)
BEGIN
    return vi+(g-(c/m)*vi)*(t-ti);
END;

EXPORT EULER()
BEGIN
    purge(g,c,m,t,vi,ti,vf,tf);
    g:=9.81; c:=12.5; m:=68.1;
    vi:=0; ti:=0;
    print();
    FOR tf FROM 0 TO 60 STEP 2 DO
        print();
        vf:=v(tf);
        print("vi = "+vi);
        print("ti = "+ti);
        print("tf = "+tf);
        print("vf("+tf+") = "+vf);
        print("");
        vi:=vf;
        ti:=tf;
        wait();
    END;
    return "Done";
END;