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Re: Plotting anomaly with a staircase function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg114764] Re: Plotting anomaly with a staircase function
  • From: "Nasser M. Abbasi" <nma at 12000.org>
  • Date: Thu, 16 Dec 2010 05:49:21 -0500 (EST)
  • References: <ieado1$rbs$1@smc.vnet.net>
  • Reply-to: nma at 12000.org

On 12/15/2010 4:53 AM, rebcabin wrote:
> Hello -- I was investigating a staircase function derived from a
> representation of a parametric polyline (concept from Differential
> Geometry), and found some plotting anomalies. In particular, sometimes
> the "risers" of the stair steps are slanted instead of the expected
> vertical. I did some fuzz testing of my function and was unable to
> find an anomaly numerically amongst a million random inputs. I
> compared my staircase against a different form built from the Matheamtica
> built-in UnitStep, and that second form does NOT show the anomaly. I
> boiled everything down to the smallest possible notebook I could, and
> would be grateful for advice from the community, if anyone has a
> moment to look at it. There should be nothing difficult or subtle,
> here, which makes it all the more puzzling!
>
> Notebook posted below.
>
> https://docs.google.com/leaf?id=0B4v0MzmZfdm8MWRlYzk3NTEtMDAzZi00YzM4LTkyZTEtYjM2ZjIxMjc4MTFk&hl=en&authkey=CPOwrzA
>

I ran your notebook in V 8, and I do not see the anomaly, here is a screen shot:

http://12000.org/tmp/dec_15_2010/stairs.png

--Nasser


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