Re: Removing banner from mtxrun output

[Aditya Mahajan <adityam@umich.edu>]

On Mon, 20 Sep 2010, Johan Sandblom wrote:

> In the modernized version of the R module (attached), which makes it
> possible to interact with the statistical programming environment R
> (http://www.r-project.org), mtxrun is used to call R on saved buffers
> containing snippets of R code. Optionally, the output from R can be
> included using \typefile. However, mtxrun includes a banner in the
> output file, example below.

Why are you using input output redirection

       R .... < \Rfile\space > \Rfile.out

rather than a simple

      R .... \Rfile\space \Rfile.out

> MTXrun |
> MTXrun | executing: R -q --save --restore
> MTXrun |
> MTXrun |> sample(1:10)
> [1]  5  3  1  9  2  6 10  8  4  7
>> sample(1:10, replace=TRUE)
> [1]  1 10  7  1  7  5  2  2 10  5


See 
http://archive.contextgarden.net/message/20100611.141914.fd6567be.en.html

but the banner still appears the first time mtxrun --ifchanged is run.

@Hans, mtxrun be completely silent when used to launch external 
programs and only give some output if --verbose is passed.


BTW, there is a serious bug in the R module: each code chunck carries a 
state with it (--save --restore), but this state can depend on which 
chunck was changed.

Consider (I don't know the R syntax on top of my head, but this gives the 
idea of the bug)

Chunk 1
\startR
  a = 10 ;
  b = 10 ;
\stopR

Chunk 2
\startR
  a = 20 ;
  b = 20
\stopR

Chunck 3
\startR
print(a+b) ;
\stopR

Run this once. The output will be 40. Now, add

c = 10 ;

in Chunk 1. Also change Chunk 3 to (add spaces so that md5 sum is 
different)

print( a + b ) ;

Now run the file again. Since Chunk 2 is not changed, it will not be run. 
Chunk 3 will see the state set by Chunk 1, and hence the output will be 
20.

This "bug" can be avoided by doing some book keeping for the external 
state (saving the file to a different name and restoring it), or by not 
using --save and --restore.

Aditya
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