Hi Robert,
On Dec 2, 5:50 am, Robert Bradshaw <[EMAIL PROTECTED]>
wrote:
> Are you saying you would like to pass in a domain when creating the
> variables? Something like
>
> sage: var('omega', domain=RR)
YES, that would be great.
>
> > Here is the error I found. The result given by omgo.simplify_full
> > ().real() is different to the one obtained by omgo.factor().
>
> Currently we're using maxima as a back end for all the calculus
> operations. This is probably due to maxima's simplifications being
> lax with branch cuts, similar to
>
> -1 = sqrt(-1)^2 = sqrt(-1) * sqrt(-1) "=" sqrt(-1 * -1) = sqrt(1) = 1
>
I see now how this comes about. Do you reckon it would help to submit
this as a bug to maxima? Errors like these make the simplify_full
function rather useless.
By the way, the assume(omega,'real') line does not have the desired
effect on simplify_full:
var('omgo zr ys cz')
assume(omgo, 'real')
omgo = (sqrt(-zr^2 + 2*ys*zr + (2*cz - zr)^2 - 2*ys*(2*cz - zr)) +
2*zr- 2*cz)/(2*zr - 2*cz)
omgo.simplify_full()
(I*sqrt(cz - ys)*sqrt(zr - cz) + zr - cz)/(zr - cz)
omgo.simplify_full()(cz=10,ys=5,zr=4).n()
1.91287092917528
omgo(cz=10,ys=5,zr=4).n()
0.0871290708247230
Useless, indeed!
Thanks again,
Stan
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