[Maxima] realpart strangeness, was: besselarray bug, was: Bessel plotting problem
biomates at telefonica.net
Fri Jun 13 05:25:05 CDT 2008
Richard Hennessy escribió:
> I think then the idea is not to tell draw where the points came from so I tried this and it works.
> (%i2) expr:expand(sum((-1)^k*2^(-v-2*k)*z^(v+2*k)/(k!*gamma(v+k+1)),k,0,100))$
> (%i3) myf(v,z):=''expr$
> (%i21) mypoints:makelist([t/2, float(realpart(myf(1/6,t/2))), float(imagpart(myf(1/6,t/2)))], t, -30,30);
> (%i20) draw3d(color=royalblue,point_size=1, points_joined=true,point_type = dot, points(mypoints));
> Now draw has no idea that the points were coming from a complex valued function, so it works.
Not exactly. In general, package draw should accept complex expressions,
plotting their real parts. The problem appears in some cases.
I have just commited a new draw version which tries to fix this:
Now, the following code works:
draw2d(explicit(bessel_j(1/6,-t), t, -3, 3)) $
Mario Rodriguez Riotorto
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