Thank you for your help Rick! Below is the output from the four commands.
~> ls -l /usr/lib/x86_64-linux-gnu/libgsl.*
lrwxrwxrwx 1 root root 20 Oct 17 17:55 /usr/lib/x86_64-linux-gnu/libgsl.so -> /usr/lib/libgsl.so.0
lrwxrwxrwx 1 root root 16 Dec 7 2015 /usr/lib/x86_64-linux-gnu/libgsl.so.19 -> libgsl.so.19.0.0
-rw-r--r-- 1 root root 2352808 Dec 7 2015 /usr/lib/x86_64-linux-gnu/libgsl.so.19.0.0
~> file /usr/lib/x86_64-linux-gnu/libgsl.*
/usr/lib/x86_64-linux-gnu/libgsl.so: broken symbolic link to /usr/lib/libgsl.so.0
/usr/lib/x86_64-linux-gnu/libgsl.so.19: symbolic link to libgsl.so.19.0.0
/usr/lib/x86_64-linux-gnu/libgsl.so.19.0.0: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=df4f3d1f505c3f6eff70f86f04fc46bb2027614d, stripped
~> ls -l /usr/lib/libgsl.*
lrwxrwxrwx 1 root root 35 Oct 20 19:32 /usr/lib/libgsl.so.0 -> /usr/lib/x86_64-linux-gnu/libgsl.so
~> file /usr/lib/libgsl.*
/usr/lib/libgsl.so.0: broken symbolic link to /usr/lib/x86_64-linux-gnu/libgsl.so
It says broken symbolic link on two occasions. Could that be the problem?
