[pstricks] Smoothing Logistic Curves

[Michael Sharpe]

Rich,

I don't see any problems when I run this code. Here's my file list and  
my final output pdf.

Michael

  *File List*
  article.cls    2007/10/19 v1.4h Standard LaTeX document class
   size10.clo    2007/10/19 v1.4h Standard LaTeX file (size option)
pstricks-add.sty    2009/03/17 v. 0.13 package wrapper for pstricks- 
add.tex (hv
)
pstricks.sty    2008/11/26 v0.40 LaTeX wrapper for `PSTricks' (RN,HV)
pstricks.tex    2009/05/19 v1.29 `PSTricks' (tvz,hv)
   xcolor.sty    2007/01/21 v2.11 LaTeX color extensions (UK)
    color.cfg    2007/01/18 v1.5 color configuration of teTeX/TeXLive
    dvips.def    1999/02/16 v3.0i Driver-dependant file (DPC,SPQR)
pstricks-add.tex    2009/05/25 v3.34 `PSTricks-add' (hv)
pst-xkey.tex    2005/11/25 v1.6 PSTricks specialization of xkeyval (HA)
  xkeyval.sty    2008/08/13 v2.6a package option processing (HA)
  xkeyval.tex    2008/08/13 v2.6a key=value parser (HA)
pst-func.sty    2008/03/21 package wrapper for pst-func.tex (hv)
pst-func.tex    2009/10/08 v0.60 `PST-func' (hv)
  ***********

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On Oct 26, 2009, at 11:26 AM, Rich Shepard wrote:

>  Thanks to Michael Sharpe (for the PostScript code for logistic and
> Gaussian curves) and Herbert Voss for fine-tuning the axes template  
> code,
> I'm much closer to achieving what I need, and understanding what I'm  
> doing,
> too.
>
>  The following code produces a nice S-curve (a logistic curve) over  
> a large
> domain on the x-axis. I assume that the jagged changes at the lower  
> left and
> upper right are the results of the asymptotic approach to the limits  
> of the
> y-axis. Is there a way to make the curve appear more smooth near the
> extremes?
>
> \documentclass[letterpaper,10pt]{article}
> \usepackage{pstricks-add,pst-func}
>
> \makeatletter
> \pst at addfams{pst-morefunc}
> \define at key[psset]{pst-morefunc}{sigma}{\def\psk at sigma{#1 }\def
> \psk at var{#1 #1 mul }}
> \define at key[psset]{pst-morefunc}{var}{\def\psk at var{#1 }\def
> \psk at sigma{#1 sqrt }}
> \define at key[psset]{pst-morefunc}{mu}{\def\psk at mu{#1 }}
> \define at key[psset]{pst-morefunc}{lscale}{\def\psk at lscale{#1 }}
> \def\gaussfn{ Euler x \psk at mu sub dup mul 2 div \psk at var div neg exp }
> \def\Scurve{1 1 Euler x \psk at mu sub \psk at lscale div neg exp add  
> div } \def\Zcurve{Euler x \psk at mu sub \psk at lscale div neg exp dup 1  
> add div }
> \makeatother
> \begin{document}
> \psset{axesstyle=axes,Dx=10,Dy=0.25,tickstyle=bottom,
>  llx=-1.5cm,lly=-1.1cm,urx=1mm,ury=1mm,
>  xAxisLabel=Domain,xAxisLabelPos={c,-0.2},
>  yAxisLabel={Membership Grade ($\mu$)},yAxisLabelPos={-14,c}}
> \begin{psgraph}(0,0)(100,1){10cm}{5cm}
>  \psplot[mu=50,lscale=10,linewidth=1.0pt,linecolor=blue]{0}{100} 
> {\Scurve}
> \end{psgraph}
>
> \end{document}
>
>
> -- 
> Richard B. Shepard, Ph.D.               |  Integrity             
> Credibility
> Applied Ecosystem Services, Inc.        |            Innovation
> <http://www.appl-ecosys.com>     Voice: 503-667-4517      Fax:  
> 503-667-8863
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