[R] Ryacas not working properly

[Marc Schwartz]

OK, after digging around for a couple of hours on this, thinking that
this might be a firewall/SELinux/"On Demand Services" problem, I have, I
think, nailed it down to two key things on FC6:

1. It requires the use of the '--enable-server' configure option for
yacas itself.

2. There is a directory permissions problem in the Ryacas package,
restricting a regular user's access to the files located in the 'yacdir'
subdirectory.

Note that in the instructions below, I also install the GSL, which
presumably is not required, but I did it anyway after noting some
warnings during the yacas build process.

One other thing, which is that when downloading the Ryacas package from
the Google site using Firefox, the file is downloaded as:

  Ryacas_0.2 3.tar.gz

Note the missing '-' between the 2 and 3.  Be sure to check for this
when saving the tarball to disk.


So here goes:


1. Install the GSL (including the devel RPM) as root:

  yum install gsl*




2. Install yacas from the source tarball using:

  ./ configure --enable-server
  make
  
  then as root:

  make install




4. Install the Ryacas package as root:

  R CMD INSTALL Ryacas_0.2-3.tar.gz


Be sure that you also have the 'XML' package from CRAN installed, which
is a dependency for Ryacas.




3. Change the permissions for /usr/local/lib/R/library/Ryacas/yacdir:

Note that the default permission for this directory after installation
is:

drwxr--r-- 2 root root  4096 Nov 19 15:17 yacdir


Thus:

 su
 chmod +x /usr/local/lib/R/library/Ryacas/yacdir


Now:

drwxr-xr-x 2 root root  4096 Nov 19 15:17 yacdir



Now in R as a regular user:

> library(Ryacas)
Loading required package: XML

> yacas("5/8 * 3/4")
[1] "Starting Yacas!"
Accepting requests from port 9734
expression(15/32)

> yacas("3/7 * 5/9")
expression(5/21)


HTH,

Marc Schwartz