Re: Beginner problem with repeat

Hello Robert,

You need an output operation like this:

 for ipp in 1..3 repeat
    ip := ip + 1
    p == plist.ip
    output("p=",p)
    output solve(eq1,precision)

OAxiom treats the enter for-loop as a single expression and only
outputs the value returned by the last statement executed. The rest
are thrown away unles you do something with them - like explicitly ask
for the 'output'.

Of course there are a lot of different ways to write this sort of
loop. I would probably do it something like this:

  )clear all
  )set message autoload off

  eq1 := p^2 + 2*P + 5 = 0
  precision := 1.e-6
  plist := [1000,2000,3000]

  for i in plist repeat
    output("p=".(i::String), solve(eval(eq1,p=i),precision).1)

---------

Normally == is only used in the Axiom interpreter for defining functions.

Regards,
Bill Page.



On 10/17/07, Robert Funnell <[email protected]> wrote:
> I just started using Axiom recently and have obtained very useful
> numerical solutions of a set of equations. I am now trying to embed
> the solve in a loop so I can easily try different parameter values,
> and I can't get it to work within the loop.
>
> Appended below is a simple test. The solve within the loop is just
> silently skipped over, while the solve outside the loop gives me the
> expected result. Am I doing something silly? Or, rather, what am I
> doing that is silly?
>
> (The comment lines marked bad1 and bad2 are attempts to make the loop
> more elegant. They don't work, but that's another story.)
>
> - Robert
>
> Test case
> ---------
>
> )clear all
> )set output algebra test_results.txt
>
> eq1 == p^2 + 2*P + 5 = 0; precision := 1.e-6;
> plist == [1000,2000,3000]
>
> --bad1 for ip in 1..3 repeat
> --bad1   p == plist.ip
> --bad2 for p in plist repeat
>
> -- for some reason the solves don't get executed
> ip := 0;
> for ipp in 1..3 repeat
>    ip := ip + 1;
>    p == plist.ip;
>    output("p=",p);
>    solve(eq1,precision)
>
> -- the following solve does get executed
> output("p=",p)
> solve(eq1,precision)
>