Re: "Unknown function" message for compiled function

[Karim Belabas <Karim.Belabas@math.u-bordeaux1.fr>]

* Ewan Delanoy [2012-05-17 11:31]:
>  I have a function below (called "polforcedshrink") that does not work (whenever I call it I get the error message " *** unknown function or error in formal parameters: "), although the interpreter remains silent at compile time.
> 
>  Can anyone tell me what's wrong with the code ?
> 
>  Thanks in advance,
> 
>  Ewan
> 
>  The code :
> 
>  polforcedshrink(paul,var,a,b,l)=
>  {
>  local(local_runner,local_c,local_adj,answer);
>  answer=[];
>  local_runner=paul;
>  for(k=1,length(l),\
>  local_c=l[k];\
>  answer=concat([subst(local_runner,var,local_c)],answer);\
>  local_adj=1-2*(local_c==b);\
>  local_runner=local_adj*((local_runner-subst(local_runner,var,local_c))/(var-local_c));\
>  );
>  return(answer);
>  }
>  ? test1=paulforcedshrink(g1,x,0,1,[1,0,0,0,0])
           ^^^^ replace by pol, it will work :-)

Cheers,

    K.B.

P.S: Some minor comments: 
- you don't need the trailing \ (since the multi-line text is already enclosed
  within braces { })

- why the 'local_' prefix in your (indeed, local) variable names; (to my
  taste) it makes the script a little harder to read.

- I am not too fond of (valid) cryptic constructs like
      local_adj=1-2*(local_c==b);
  (ab)using boolean truth values as integers. Why not
      local_adj = if (local_c==b, -1, 1);
  ?

- any particular reason to stick to pari-2.3.2 ?
-- 
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite Bordeaux 1          Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation    http://www.math.u-bordeaux1.fr/~belabas/
F-33405 Talence (France)       http://pari.math.u-bordeaux1.fr/  [PARI/GP]
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