Linker Problems with Matlab on Linux?

nospam@example.com (Martin) — Sun, 06 Jan 2008 22:18:02 +0100

If you're writing a C/C++ program using Matlab libraries on a linux system you get errors like this if the system isn't configured properly:

/usr/bin/ld: warning: libut.so, needed by /path/removed/libmx.so, not found (try using -rpath or -rpath-link)

The reason can be found in the ld manpage: libmx.so has more dependencies, but ld can't find them. The -rpath-link linker switch might be a solution, but Linux systems have a central place for this kind of config: /etc/ld.so.conf.

If you have a directory called /etc/ld.so.conf.d/, create a file there with no other contents than the path to your matlab libs ($MATLAB/bin/glnx86 for i386) and call it matlab.conf or something like that (it needs a .conf suffix!). If this directory does not exists, append a line with this path to /etc/ld.so.conf. Then, re-run ldconfig and your problem should be solved.

Reducing PDF file size

nospam@example.com (Martin) — Sat, 23 Dec 2006 18:11:38 +0100

Sometimes, especially when I create PDF files with lots of images, I end up with huge PDF files, sometimes in the gigabyte range, even though the actual images themself were just a couple of megabytes.
These files aren't just impractical, but most printers can't handle them so basically they are useless.

While it's probably better to tackle the problem where it begins (in my case, the PDF file printer driver) I decided to go for a more 'hacky' approach: I wrote a script which cleans and recompresses the PDF files. This is useful because I noticed that quite a lot of PDF files (especially ones I didn't create myself) are unnecessarily huge and contain PDF errors.
This script passes the PDFs through all available ghostscript filters until it ends up with a nice new and shiny PDF.

Warning: the process is ressource-consuming, can take a while and will definitely take up some disk space.

By now way do I guarantee for any file loss or damage. USE AT YOUR OWN RISK.



<br />
#!/bin/bash<br />
<br />
if [ -z $1 ]; then<br />
        echo "Usage: cleanpdf infile.pdf [outfile.pdf]"<br />
        exit 1<br />
fi<br />
<br />
infile=$1<br />
wipe=false<br />
<br />
if [ -z $2 ]; then<br />
        echo no thingy given<br />
        outfile=$1<br />
        wipe=true<br />
else<br />
        if [ -e $2 ]; then<br />
            echo "Error: file $2 already exists, won't overwrite."<br />
            exit 2<br />
        fi<br />
        outfile=$2<br />
fi<br />
<br />
tmpfile1=tmpfilecleanpdf123131212.ps<br />
tmpfile2=tmpfilecleanpdf123131412.ps<br />
<br />
echo "Converting to PostScript..."<br />
pdf2ps $infile $tmpfile1<br />
echo "Cleaning PostScript..."<br />
ps2ps $tmpfile1 $tmpfile2<br />
if [ $wipe = true ]; then<br />
        echo "Wiping original..."<br />
        rm $infile<br />
fi<br />
echo "Converting clean PostScript to PDF..."<br />
ps2pdf $tmpfile2 $outfile<br />
rm $tmpfile1 $tmpfile2<br />
echo "Done."<br />

mbant's technical notes - Scripts & Code

Linker Problems with Matlab on Linux?

Reducing PDF file size