If you run into problems with Octave, try adding this function:
https://code.google.com/p/pmtk3/source/browse/trunk/toolbox/Optimization/lbfgsC.m?r=1186
If you run into problems with Octave, try adding this function:
https://code.google.com/p/pmtk3/source/browse/trunk/toolbox/Optimization/lbfgsC.m?r=1186