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RE: Avoiding Null output marker from a function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg92499] RE: Avoiding Null output marker from a function
  • From: "E. Martin-Serrano" <eMartinSerrano at telefonica.net>
  • Date: Wed, 1 Oct 2008 18:35:47 -0400 (EDT)
  • References: <200810011111.HAA11613@smc.vnet.net>

Bill,

I think these two similar examples would do. (Maybe Anthony is thinking of
other situations, but these seem to pertain to the same inconvenience he is
talking about).

In[1]:= f[x_] := 20 x^3 + 3 x ^5

In[2]:= Manipulate[{If[g, Plot[f[x], {x, -  Pi, Pi}, PlotStyle -> Red]],
                 
  If[g1, Plot[f'[x], {x, - Pi, Pi}, PlotStyle -> Green]],
                 
  If[g2, Plot[f''[x], {x, -Pi, Pi}, PlotStyle -> Blue]]},
 {g, {True, False}},
 {g1, {True, False}},
 {g2, {True, False}}
 ]

In[3]:= Manipulate[Show[If[g, Plot[f[x], {x, -  Pi, Pi}, PlotStyle -> Red]],
                 
  If[g1, Plot[f'[x], {x, - Pi, Pi}, PlotStyle -> Green]],
                 
  If[g2, Plot[f''[x], {x, -Pi, Pi}, PlotStyle -> Blue]]],
 {g, {True, False}},
 {g1, {True, False}},
 {g2, {True, False}}
 ]

When the Booleans g, g1 and g2 are unchecked (set to False) the Plot
function renders the symbol 'Null'. The convenient output would be void,
just to erase the corresponding curve. In the regular situation the symbol
=B4'Null' must be dropped "manually" to keep the compound plot clean.

$Version = 6.0.1

E. Martin-Serrano
______________________________________________

-----Original Message-----
From: Bill Rowe [mailto:readnews at sbcglobal.net]
Sent: mi=E9rcoles, 01 de octubre de 2008 12:11
To: mathgroup at smc.vnet.net
Subject: [mg92499] Re: Avoiding Null output marker from a function

On 9/30/08 at 7:35 AM, Anthony.J.Mannucci at jpl.nasa.gov (amannuc1)
wrote:

>I am having difficulties that the documentation has not resolved to
>date for me. It is this:

<problem description snipped>

Your problem description failed to include any details of the
function creating the problem. Without those details which
should include the Mathematica code for the function, it isn't
really possible to offer meaningful suggestions as to how to fix
the problem.



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