R help - Jul 2005 - unexpected behavior in bwplot

R-2.1.1 on windows XP

I just noticed something unpleasant when using bwplot (from lattice). 

In order to satisfy a wish from a client, I needed to produce sets of boxplots
conditioned by another factor. My client didn't like the look of the
boxplots (by default, they have a star to mark the median, instead of the
commonly used line). I told him "no problem" dumped panel.bwplot,
added a line at the median, commented out the star, and sourced it back in as
panel.mybwplot.

Then I tried to call it with bwplot(...,panel="panel.mybwplot"), but
this hit two roadblocks. The first one was relatively easy: it didn't find
the function current.viewport (from grid). Explicitely loading the package grid
was sufficient (current.viewport is exported there). But then it stopped on
chooseFace. It was not obvious to find where chooseFace was (in lattice, but not
as an exported function in the namespace) and how to make it callable. I finally
clobbered it by defining chooseFace<-lattice:::chooseFace. This certainly
worked but is very inelegant. Could anyone point me to cleaner ways to do this?

On the other hand, I would have preferred if panel.bwplot would not use
functions not exported to the outer namespace (or if lattice would make sure
that all functions called in the standard panel functions were exported to the
outer namespace). It is very common that we have to slightly modify standard
panel functions and it is quite annoying having to chase for evenually hidden
functions called by them. Comments?

Thanks in advance,

Christian Ritter
Functional Specialist Statistics
Shell Coordination Centre S.A.
Monnet Centre International Laboratory, Avenue Jean Monnet 1, B-1348
Louvain-La-Neuve, Belgium

Tel: +32 10 477  349 Fax: +32 10 477 219
Email: christian.ritter@shell.com
Internet: http://www.shell.com/chemicals



	[[alternative HTML version deleted]]

I had a similar problem when trying to modify a function from lattice. 
I second the opinion that it 
would be nice if lattice exported more things.  My soulution was to
give my function the same 
environment as the one I had copied, i.e. try:

environment(panel.mybwplot) <- environment(panel.bwplot)

I have included a line like this at the end of the script file that
defines my new/modified lattice
functions, and as long as lattice is loaded first (could wrap the above
in the body of an if 
statement that calls library or require) then everything works fine
(having the same environment
lets the new function find the non-exported functions).

Hope this helps,



Greg Snow, Ph.D.
Statistical Data Center, LDS Hospital
Intermountain Health Care
greg.snow at ihc.com
(801) 408-8111
>>> "Ritter, Christian C GSMCIL-GSTMS/2" <christian.ritter
at shell.com>
07/12/05 05:08AM >>>
R-2.1.1 on windows XP

I just noticed something unpleasant when using bwplot (from lattice). 

In order to satisfy a wish from a client, I needed to produce sets of
boxplots conditioned by another factor. My client didn't like the look
of the boxplots (by default, they have a star to mark the median,
instead of the commonly used line). I told him "no problem" dumped
panel.bwplot, added a line at the median, commented out the star, and
sourced it back in as panel.mybwplot. 

Then I tried to call it with bwplot(...,panel="panel.mybwplot"), but
this hit two roadblocks. The first one was relatively easy: it didn't
find the function current.viewport (from grid). Explicitely loading the
package grid was sufficient (current.viewport is exported there). But
then it stopped on chooseFace. It was not obvious to find where
chooseFace was (in lattice, but not as an exported function in the
namespace) and how to make it callable. I finally clobbered it by
defining chooseFace<-lattice:::chooseFace. This certainly worked but is
very inelegant. Could anyone point me to cleaner ways to do this? 

On the other hand, I would have preferred if panel.bwplot would not use
functions not exported to the outer namespace (or if lattice would make
sure that all functions called in the standard panel functions were
exported to the outer namespace). It is very common that we have to
slightly modify standard panel functions and it is quite annoying having
to chase for evenually hidden functions called by them. Comments? 

Thanks in advance,

Christian Ritter
Functional Specialist Statistics
Shell Coordination Centre S.A.
Monnet Centre International Laboratory, Avenue Jean Monnet 1, B-1348
Louvain-La-Neuve, Belgium

Tel: +32 10 477  349 Fax: +32 10 477 219
Email: christian.ritter at shell.com 
Internet: http://www.shell.com/chemicals 



	[[alternative HTML version deleted]]

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On 7/12/05, Ritter, Christian C GSMCIL-GSTMS/2
<christian.ritter at shell.com> wrote:
> R-2.1.1 on windows XP
> 
> I just noticed something unpleasant when using bwplot (from lattice).
> 
> In order to satisfy a wish from a client, I needed to produce sets of
boxplots conditioned by another factor. My client didn't like the look of
the boxplots (by default, they have a star to mark the median, instead of the
commonly used line). I told him "no problem" dumped panel.bwplot,
added a line at the median, commented out the star, and sourced it back in as
panel.mybwplot.
> 
> Then I tried to call it with bwplot(...,panel="panel.mybwplot"),
but this hit two roadblocks. The first one was relatively easy: it didn't
find the function current.viewport (from grid). Explicitely loading the package
grid was sufficient (current.viewport is exported there). But then it stopped on
chooseFace. It was not obvious to find where chooseFace was (in lattice, but not
as an exported function in the namespace) and how to make it callable. I finally
clobbered it by defining chooseFace<-lattice:::chooseFace. This certainly
worked but is very inelegant. Could anyone point me to cleaner ways to do this?
> 
> On the other hand, I would have preferred if panel.bwplot would not use
functions not exported to the outer namespace (or if lattice would make sure
that all functions called in the standard panel functions were exported to the
outer namespace). It is very common that we have to slightly modify standard
panel functions and it is quite annoying having to chase for evenually hidden
functions called by them. Comments?
> 
I agree that this is a problem, but I don't know what a good solution
is. I can certainly export more functions (writing documentation is
the only hard work). However, chooseFace is a hack which definitely
isn't worth exporting.

I think the best solution in this case is for me to rewrite
panel.bwplot using lattice wrappers line panel.points and panel.lines
(and panel.rect, which doesn't exist yet). That may take a little
time. Please let me know of other similar situations if you encounter
them.

Deepayan