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Re: avoid spurious vertical segment in step function plot


Another interesting and useful solution.  Thanks.

BobHanlon at aol.com wrote:
> 
> This may look familiar ...
> 
> plt = Plot[
>       UnitStep[x] - UnitStep[x - 1] + UnitStep[x - 2] -
>         UnitStep[x - 3], {x, -1, 4}, Frame -> True, Axes -> False,
>       PlotRange -> {-.2, 1.2}];
> 
> threshold = 0.5;
> 
> Show[plt //. {Line[{start___, {x1_, y1_?(# < threshold &)}, {x2_,
>                 y2_?(# > threshold &)}, end___}] :>
>           Sequence[Line[{start, {x1, y1}}], Line[{{x2, y2}, end}]],
>         Line[{start___, {x1_, y1_?(# > threshold &)}, {x2_,
>                 y2_?(# < threshold &)}, end___}] :>
>           Sequence[Line[{start, {x1, y1}}], Line[{{x2, y2}, end}]]}];
> 
> There is probably some way to work these two rules into one; however, it
> didn't leap immediately to mind.
> 
> In a message dated 5/2/2000 1:01:33 AM, murray at math.umass.edu writes:
> 
> >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}]
> >
> 
> Bob
> 
> BobHanlon at aol.com

-- 
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


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