There are varying degrees of stuck.

Sometimes applying the methods above (with a modicum of time and patience) works.
Sometimes, not.

Try the easy stuff first, and be careful with the vise trick - you can bend the frame.
Heat never works because aluminum expands faster than steel.

Even sawing it out can be ineffectual, if the bond between the steel and aluminum is stronger than the parent metal, and reaming is perilous.

The only method I have never tried is drilling a hole in the bottom bracket shell to insert a steel battering ram.

....Don't lose hope too soon though. The majority of stuck posts will come out.