Maybe the bug is in complex-number-p; see bug 1458733.
Barton
maxima-bounces at math.utexas.edu wrote on 03/22/2007 09:38:27 AM:
> On 3/22/07, Juan Pablo Romero Bernal <jromerobernal at gmail.com> wrote:
> > (%i2) integrate((2*x+1)*sin(x),x,0,4),numer;
> > Maxima encountered a Lisp error:
>
> It turns out that this is a simplification bug:
>
> exp(-%i*x),numer => internal error
> log(-%i*x),numer => internal error
> sqrt(-%i*x),numer => internal error
>
> The error shows up in double-float-eval:
> Error in ZEROP [or a callee]: ((MTIMES SIMP) -1.0 $X) is not of
> type NUMBER.
>
> This was introduced in 1.16 or 1.17, when double-float-eval started
> being used in simp.lisp. This change also introduced another bug:
>
> sqrt(-1.0) => 1.0 %i + 6.123E-17
> versys
> (-1.0)^(1/2) => 1.0 * %i
>
> This is because simpsqrt calls the floating-point square root routine
> directly, rather than going through simpexpt, but sqrt(x) should
> always be exactly equivalent to x^(1/2).
>
> -s
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