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RE: Problems with TickFunction

• To: mathgroup at smc.vnet.net
• Subject: [mg40274] RE: [mg40260] Problems with TickFunction
• From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
• Date: Sat, 29 Mar 2003 05:19:15 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

>-----Original Message-----
>From: Michael A. Gilchrist [mailto:mike at unm.edu]
To: mathgroup at smc.vnet.net
>Sent: Friday, March 28, 2003 10:32 AM
>To: mathgroup at smc.vnet.net
>Subject: [mg40274] [mg40260] Problems with TickFunction
>
>
>Hi,
>
>I am trying to use the routines in  ExtendGraphics`Tick`. 
>However, I keep
>getting the same error when trying to use these functions.  As far as I
>can tell it stems from the fact that the subfunction TickPosition,
>although defined, doesn't return any numbers
>
>Here's an example of a session
>
>Load Package
>
>	In[12]:=
>		 <<"ExtendGraphics`Ticks`"
>
>Try and run TickFunction
>
>	In[15]:=
>		 TickFunction[1,2,MajorStyle->{Thickness[0.02]},
>  	MajorLength->{0.06,0}]
>
>	Transpose::nmtx: The first two levels of the one-dimensional list
>	{TickPosition[1,2,8],<<40>>[TickPosition[1,2,8]]} cannot be
transposed.
>
>	Transpose::nmtx: The first two levels of the one-dimensional list
>	
>{TickPosition[1,2,8],<<40>>[<<1>>],{0.06,0},{Thickness[0.02]}} cannot be
>	transposed.
>
>	Join::heads: Heads Transpose and TickPosition at positions 1 and 2
are
>	expected to be the same.
>
>	Join[Transpose[{TickPosition[1,2,8],
>      	
>ExtendGraphics`Ticks`Private`TrimDecimal[TickPosition[1,2,8]],{
>0.06, 0},
>	{Thickness[0.02]}}], 
>TickPosition[{32,,{0.003125,0},{Thickness[0.001]}}]]
>
>
>If I inquire about TickPosition it appears to be defined
>
>	In[13]:=
>		?TickPosition
>
>	Out[14]=
>	TickPosition[ min, max, num] returns a list of at most num nicely
rounded
>	positions between min and max.  These can be used for tick mark
positions.
>
>However, when used the function just returns the command used 
>to call it
>	In[14]:=
>	TickPosition[1, 2, 5]
>
>	Out[14]=
>	TickPosition[1,2,5]
>
>
>Has anyone else seen this problem or does anyone have any ideas what's
>going wrong here.
>
>Thanks in advance,
>
>Mike Gilchrist
>
>
>BTW: I just reinstalled the ExtendGraphics files and that didn't help
>
>
>

Mike,

what to do in such a case? You've already found out that there is a problem
with 

	TickPosition[1,2,8]


So have a look at it:

In[153]:= Begin["ExtendGraphics`Ticks`Private`"]
Out[153]= "ExtendGraphics`Ticks`Private`"
(this is a trick as to remove clutter in the output following, 
we're going to step right into the private part of the package)

In[154]:= ?? TickPosition
"TickPosition[ min, max, num] returns a list of at most num nicely rounded 
positions between min and max.  These can be used for tick mark positions."

 TickPosition[x0_Real, x1_Real, num_Integer?Positive] := 
    Block[{dist, scale, min, max, i, delta, space}, 
       space = {1.`, 2.`, 2.5`, 5.`, 10.`}; 
       dist = (x1 - x0)/num; 
       scale = 10.`^Floor[Log[10, dist]]; dist = dist/scale; 
       If[dist < 1.`, dist *= 10.`; scale = 10.`]; 
       If[dist >= 10.`, dist = 10.`; scale *= 10.`]; 
       delta = First[Select[space, #1 >= dist &]] scale; 
       min = Ceiling[x0/delta] delta; 
       Table[Floor[x/delta + 0.5`] delta, {x, min, x1, delta}]]

In[155]:= End[]
Out[155]= "ExtendGraphics`Ticks`Private`"
(we have seen enough and leave)


In[157]:= TickFunction[1., 2., MajorStyle -> {Thickness[0.02]}, 
  MajorLength -> {0.06, 0}]

...works!


--
Hartmut Wolf