Many thanks! The output of "pkg list" is
Package Name | Version | Installation directory
--------------+---------+-----------------------
control *| 2.6.6 | /usr/share/octave/packages/control-2.6.6
general *| 1.3.4 | /usr/share/octave/packages/general-1.3.4
image *| 2.2.2 | /usr/share/octave/packages/image-2.2.2
io *| 2.2.4 | /usr/share/octave/packages/io-2.2.4
ltfat *| 2.0.1 | /usr/share/octave/packages/ltfat-2.0.1
signal *| 1.3.0 | /usr/share/octave/packages/signal-1.3.0
specfun *| 1.1.0 | /usr/share/octave/packages/specfun-1.1.0
statistics *| 1.2.3 | /usr/share/octave/packages/statistics-1.2.3
I am hoping to use wavelets for image processing, so I do need some of these other packages. However, if I start octave (version 3.8.1), under linux (Ubuntu 14.04 64 bit) with
octave --no-init-fileand then enter the commands
pkg load ltfatwfiltinfo('db2') the same errors as before are produced. I've even tried starting octave in a different directory, to ensure it's not picking up anything from some of my own programs. I suppose I could upgrade octave to 3.8.2... Anyway, thanks again!