David,
Your example shows a bug in odelin, I think. I'm guessing that odelin uses
$ratsimp when it should use sratsimp. Consider:
(%i22) odelin('diff(y,x,2)+7*y,y,x);
(%o22) {%e^(-sqrt(-7)*x),%e^(sqrt(-7)*x)}
(%i23) ?print(%);
(($SET SIMP)
((MEXPT SIMP) $%E
((MTIMES SIMP) -1 ((MEXPT SIMP) -7 ((RAT SIMP) 1 2)) $X))
((MEXPT SIMP IRREDUCIBLE FACTORED) $%E
((MTIMES SIMP RATSIMP) ((MEXPT SIMP) -7 ((RAT SIMP) 1 2)) $X)))
(%o23) {%e^(-sqrt(-7)*x),%e^(sqrt(-7)*x)}
(%i24) expand(%o22,0);
(%o24) {%e^(-sqrt(7)*%i*x),%e^(sqrt(7)*%i*x)}
(%i25) ?print(%);
(($SET SIMP)
((MEXPT SIMP) $%E
((MTIMES SIMP) -1 ((MEXPT SIMP) 7 ((RAT SIMP) 1 2)) $%I $X))
((MEXPT SIMP) $%E
((MTIMES SIMP) ((MEXPT SIMP) 7 ((RAT SIMP) 1 2)) $%I $X)))
(%o25) {%e^(-sqrt(7)*%i*x),%e^(sqrt(7)*%i*x)}
So (%o22) and (%o24) aren't the same (but algebraically the
same).
I suggest marking such tests as known failures until the $ratsimp /
sratsimp
bug is fixed.
Barton
-----maxima-bounces at math.utexas.edu wrote: -----
>To: <maxima at math.utexas.edu>
>From: RTATECH\" <David.Billinghurst at riotinto.com>
>Sent by: maxima-bounces at math.utexas.edu
>Date: 12/09/2007 08:39AM
>Subject: Problems with testsuite
>
>I have been working through the failures in the
>share/contrib/diffequations/tests testsuite. I have been able to fix
>most of them with some minor editing, such as adding brackets to the
>expected solutions, but I cannot understand or work around some of the
>failures. The answers appear identical to those expected.
>
>I have tried maxima-5.9.13 under Windows/gcl, CVS maxima under
>Windwos/gcl and CVS maxima under cygwin/clisp.
>
>As an example consider the following:
>
>/* j.mac */
>(load('contrib_ode), 0);
>0;
>
>odelin('diff(y,x,2)+7*y,y,x);
>set (%e^-(sqrt(-7)*x),%e^(sqrt(-7)*x));
>
>
>When run in maxima with the command batch("j.mac",'test) the output is
>
>
>Input:
> 2
> d y
>odelin(7 y + ---, y, x)
> 2
> dx
>
>
>Result:
>...trying factor method
>...solving 1 equations in 1 variables
> - sqrt(- 7) x sqrt(- 7) x
>{%e , %e }
>
>This differed from the expected result:
> - sqrt(- 7) x sqrt(- 7) x
>{%e , %e }
>
>
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