Re: Out of Order Evaluation

[Charles Berry <ccberry@ucsd.edu>]

Andreas Leha <andreas.leha <at> med.uni-goettingen.de> writes:

> 
> Hi Michael,
> 
> Michael Weylandt <michael.weylandt <at> gmail.com> writes:
> 
> > Hi, 
> >
> > I want to put a summary of my analysis at the beginning of a document
> > using results calculated at the end of the document. Is this possible?

[snip]

> >
> > Is this possible in a single pass? 


Not quite. The method suggested by Andreas computes the result twice. If
there is any randomness in the results (as in the example) you will get a 
different answer in the summary than when the block is later evaluated.

> > I've played with #+NAME and
> > <<block()>> but haven't gotten the out-of-order evaluation quite
> > right.

You can use

#+results: the-mean

before 

#+NAME: the-mean
#+begin_src R
mean(x)
#+end_src

which is after 'theanalysis' block.

And if the format is not pleasing add a filter that reformats the result.


> >
> > Michael
> >
> 
> How about something along:
> 
> --8<---------------cut here---------------start------------->8---
> #+TITLE: Test
> #+AUTHOR: Michael Weylandt
> #+PROPERTY: header-args:R :session *__R__* :exports both
> 
> * Summary
> The mean result was src_R[:exports results :var
analysisresults=theanalysis()]{mean(unlist(analysisresults))}
> 
> * Analysis, 
> We do some complicated calculations: 
> 
> #+name: theanalysis
> #+BEGIN_SRC R
> x <- rnorm(5)
> #+END_SRC
> --8<---------------cut here---------------end--------------->8---


It might be better to mark all the blocks in the doc ':eval never'
and ':exports code' or ':exports none' and put blocks before the first 
headline that do all the calcs from noweb references, and put the #+results
lines (if you need them) wherever you want them in the doc. Like so:



--8<---------------cut here---------------start------------->8---
#+TITLE: Test
#+AUTHOR: Michael Weylandt
#+PROPERTY: header-args:R :session *__R__* :exports both


#+NAME: master
#+BEGIN_SRC R :noweb yes :results silent :exports results
<<theanalysis>>
#+END_SRC

* Summary


The mean result was  src_R[:exports results]{mean(x)}

* Analysis, 
We do some complicated calculations: 

#+name: theanalysis
#+BEGIN_SRC R :eval never :exports code
x <- rnorm(5)
#+END_SRC

--8<---------------cut here---------------end--------------->8---

IMO, needing ':exports results' for inline src blocks is a bug not a
feature. 

HTH,

Chuck