#!/usr/bin/perl
# tab2bugs

# Memory efficient script for turning a tabular MCMC
# output file into BUGS output files

# Darren Wilkinson
# d.j.wilkinson@ncl.ac.uk
# http://www.staff.ncl.ac.uk/d.j.wilkinson/


$filestem=$ARGV[0];
$filein=$filestem.".tab";
$fileout=$filestem.".out";
$fileind=$filestem.".ind";

unless ($filestem)
  {
    print STDERR "Usage: tab2bugs <file>
<file>.tab is a tabular MCMC output file.\n";
    exit (1);
  }

unless (-e $filein)
  {
    print STDERR "File $filein does not exist.\n";
    exit (1);
  }

print "Parsing $filein into $fileout and $fileind.\n";
open(FILEOUT,">".$fileout);
open(FILEIND,">".$fileind);

open(FILEIN,$filein);
$_=<FILEIN>;
chop;
@head=split;
close(FILEIN);
print "$#head variables.\n";

$count=1;
$colind=1;
while ($colind <= $#head)
  {
    print "Parsing variable $colind - $head[$colind]\n";
    open(FILEIN,$filein);
    $header=<FILEIN>;
    $start=$count;
    while (<FILEIN>)
      {
	chop;
	@linebits=split;
	print FILEOUT "$linebits[0] $linebits[$colind]\n";
	$count=$count+1;
      }
    $end=$count-1;
    print FILEIND "$head[$colind] $start $end\n";
    $colind=$colind+1;
    close(FILEIN);
  }

close(FILEOUT);
close(FILEIND);
print "Finished.\n";

exit (0);