error message if they mistakenly use matrices that are not column vectors with
the general purpose optimizers.

new bounds constrained solver.

images were given.

pyramid_down and you give it the downsampling amount as a template argument.

a special version of it that is optimized for this case.

--HG--
rename : examples/image_ex.cpp => examples/fhog_ex.cpp

representation.

about how they schedule their initial step sizes.  In particular, they will try
to take step sizes that are similar to previously used sizes via a trust region
style scheduling.

backtracking_line_search() by making it use 3rd degree polynomial interpolation
after the first step.  Also made it more robust to alpha inputs with improper
signs.