Possible bug in Opacity[] with plotting function that uses UnitStep?
- To: mathgroup at smc.vnet.net
- Subject: [mg105593] Possible bug in Opacity[] with plotting function that uses UnitStep?
- From: "Nasser M. Abbasi" <nma at 12000.org>
- Date: Thu, 10 Dec 2009 04:57:46 -0500 (EST)
- Reply-to: "Nasser M. Abbasi" <nma at 12000.org>
Version 7 on windows XP sp2.
This is really a strange one, it seems like a "bug", but if not, then what
is it?
I have a function defined with UnitStep[]. I plot it using Plot and using
Filling->Axis.
The filling works ok across all the plot range even with different
FillingStyles for the color.
But when I use Opacity[] to change the filling Style more, then only _part_
of the plot is now affected by the Opacity[] and the other part is not.
Compare the following 2 plots to see:
y = -400*UnitStep[x - 100.8] + 8*(x - 63.4)*UnitStep[x - 63.4]
-8*(x - 43.2)*UnitStep[x - 43.2] + 221.3
Plot[y, {x, 0, 144},
Filling -> Axis,
FillingStyle -> {Opacity[0.5], Blue},
Frame -> True]
Plot[y, {x, 0, 144},
Filling -> Axis,
FillingStyle -> Blue,
Frame -> True]
--Nasser