HP Forums - help: euler() prg on home mode

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:

// file euler.hppprgm
export euler()
BEGIN
    local g,c,m,t;
    local vi,ti,vf,tf,iteration;
    //local v;
    purge(g,c,m,t,vi,ti,vf,tf);
    v(t):= vi+(g-(c/m)*vi)*(t-ti);
    g:=9.81; c:=12.5; m:=68.1;
    vi:=0;
    ti:=0;
    iteration:=1;
    print; // clear terminal view (output)
        print("euler");
    print("press [↓] for next iteration" );
    print("press [on] for exit" );
    wait(1);   
    FOR tf FROM 0 TO 10 STEP 2 DO
        print; // clear terminal view (output)
        print("iteration = "+iteration);
        vf:=v(tf);
        print("vi = "+vi+" m/s");
        print("ti = "+ti+" s");
        print("tf = "+tf+" s");
        print("vf("+tf+") = "+vf+" m/s");
        print("");
        vi:=vf;
        ti:=tf;
        iteration:=iteration+1; 
        wait();
    END;
    print("Iterations finished," );
    return("Done");
END; 

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

I managed to run it by doing the following trick.
Icomment the line // v(t):= vi+(g-(c/m)*vi)*(t-ti);
and I put in the line of entry (CAS MODE) the expression
v(t):= vi + (g- (c / m) * vi) * (t-ti);

euler() returns [] =(
but
[shift][1](program editor) euler
[DEBUG][CONT] [enter] ...[enter] ... ok
The program shows me screen by screen what I want
vi=0 m/s, ti=0 s , tf=0 s
v(0) = 0 m/s

vi=0, ti=0, tf=2
v(2) = 19.62 m/s

vi=19.62 m/s, ti=2 s, tf=4 s
v(4) = 32.04 m/s

vi=32.04 m/s, ti=4 s, tf=6 s
v(6") = 39.90 m/s
...

Please someone can help me by rewriting the above code to work well

Thanks

PS: In CAS mode if it works fine but how can I clean each screen? The print; command does not seem to be working. I have to clean each screen because the terminal view does not progress after the first impression screen is completed, (even hp-prime is a single process) should allow split screen and more of a process as did the hp48,

PHP Code:

// file euler1.hppprgm
// version simple MODO CAS
#cas
  euler1():=
  BEGIN
    local g,c,m,t;
    local vi,ti,vf,tf,iteration;
    local v;
    purge(g,c,m,t,vi,ti,vf,tf);
    v(t):= vi+(g-(c/m)*vi)*(t-ti);
    g:=9.81; c:=12.5; m:=68.1;
    vi:=0;
    ti:=0;
    iteration:=1;
    PRINT(); // clear terminal view (output)
    print("euler1");
    print("press [↓] for next iteration" );
    print("press [on] for exit" );
    wait(1);      
    FOR tf FROM 0 TO 10 STEP 2 DO
      PRINT(); // clear terminal view (output)
      print("iteration = "+iteration);
      vf:=v(tf);
      print("vi = "+vi+" m/s");
      print("ti = "+ti+" s");
      print("tf = "+tf+" s");
      print("vf("+tf+") = "+vf+" m/s");
      print("");
      vi:=vf;
      ti:=tf;
      iteration:=iteration+1; 
      wait();
    END;
    print("Iterations finished" );
    return("Done");
  END;
#end 

Debug mode does not work for CAS MODE = (, for this reason I want to create it in HOME MODE

(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;

Thanks toml_12953, but the file euler1.hppprgm does not clean the terminal view why?

Version calling an external function v(t)

PHP Code:

// file euler2.hppprgm
// version simple MODO HOME (NUM)
local g;c;m;t;
local vi;ti;vf;tf;iteration;

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

export euler2()
BEGIN
  purge(g,c,m,t,vi,ti,vf,tf);
  g:=9.81; c:=12.5; m:=68.1;
  vi:=0;
  ti:=0;
  iteration:=1;
  print; // clear terminal view (output)
  print("press [↓] for next iteration" );
  print("euler2");
  print("press [on] for exit" );
  wait(1);   
  FOR tf FROM 0 TO 10 STEP 2 DO
    print; // clear terminal view (output)
    print("iteration = "+iteration);
    vf:=v(tf);
    print("vi = "+vi+" m/s");
    print("ti = "+ti+" s");
    print("tf = "+tf+" s");
    print("vf("+tf+") = "+vf+" m/s");
    print("");
    vi:=vf;
    ti:=tf;
    iteration:=iteration+1; 
    wait();
  END;
  print("Iterations finished" );
  return("Done");
END; 

Some alternative way for file euler2.hppprgm but without call an external function v(t) and not #cas...end prgm, I think the CAS() command is required

(05-30-2017 04:18 PM)compsystems Wrote: [ -> ]Thanks toml_12953, but the file euler1.hppprgm does not clean the terminal view why?

Have you tried

print();

instead of

print; ?

Tom L

Thanks again
The solution we do not remember
print() in CASS prgm prints NULL
PRINT() clears the terminal view

Please HP-prime team try to solve this problem with a specific catalog for each CAS/HOME mode and, in the program editor, please check that the program names can not be compiled if it is a reserved system word

Pending (home) version without subroutines of euler2.hppprgm

Thanks