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RE: avoid spurious vertical segment in step function plot

• To: mathgroup at smc.vnet.net
• Subject: [mg23367] RE: [mg23327] avoid spurious vertical segment in step function plot
• From: "Higinio Ramos Calle" <higra at gugu.usal.es>
• Date: Thu, 4 May 2000 02:59:34 -0400 (EDT)
• References: <200005020443.AAA29169@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

----- Original Message -----
From: Murray Eisenberg <murray at math.umass.edu>
To: mathgroup at smc.vnet.net
Subject: [mg23367] [mg23327] avoid spurious vertical segment in step function plot


> Several packages available from MathSource deal with eliminating the
> spurious parts of plots of discontinuous functions across vertical
> asymptotes.
>
> Is there some simple way of dealing with the similar problem of
> eliminating the spurious vertical line segment in plotting a function
> with jumps -- for example, in the following?
>
>   Plot[UnitStep[x], {x, -1, 1}]
>
> --
> Murray Eisenberg                     murray at math.umass.edu
> Mathematics & Statistics Dept.       phone 413 549-1020 (H)
> Univ. of Massachusetts                     413 545-2859 (W)
> Amherst, MA 01003-4515


I  have taken the function UnitStep[x-1] instead UnitStep[x] because in the
last case the vertical line is coincident with the y-axis.
The idea is to plot the function a little before the problematic point
 where exists a vertical asymptote) and a little after this point.

dib1=Plot[UnitStep[x-1], {x, 0, .99999},PlotStyle->RGBColor[1,0,0],
    DisplayFunction->Identity];

dib2=Plot[UnitStep[x-1], {x, 1.00001, 2},PlotStyle->RGBColor[1,0,0],
    DisplayFunction->Identity];

Show[{dib1,dib2},DisplayFunction->$DisplayFunction]

H. Ramos

• References:
  • avoid spurious vertical segment in step function plot
    • From: Murray Eisenberg <murray@math.umass.edu>