I see some very useful files and commands at Matlab central, and
wonder why Mathworks does not add these to the official Matlab
release? This will make using these files/commands easier, so
that, for example, when sending an .m file to someone, they
do not have to go download some additional files from matlab
central first to the code.

Just for an example, there is the GUI layout manager toolbox

http://www.mathworks.com/matlabcentral/fileexchange/27758-gui-layout-toolbox

And the factorize() and inverse() commands in

http://www.mathworks.com/matlabcentral/fileexchange/24119

And the export_fig command, and many more.

What stops Mathworks from integrating some of the these
good submissions into core Matlab? It seems to me that someone
at Mathworks should be looking at matlab central all the time
picking the best and useful submission, and integrating into
Matlab.

--Nasser

I've wondered about this myself.

If it's an intellectual property issue, then payment (monetary or other form of reimbursement such as waived charges for license maintenance or a free toolbox) could be an option for the authors of high-quality FEX submissions that fill a gap.

Even something as simple (but non-intuitive) as Roger Stafford's numerically robust method to calculate the angle between two 3D vectors (angle = atan2(norm(cross(a,b)),dot(a,b))) would be a nice built-in function.

"Mark Shore" <mshore@magmageosciences.ca> wrote in message 
news:ienj53$6l3$1@fred.mathworks.com...
> I've wondered about this myself.
>
> If it's an intellectual property issue, then payment (monetary or other 
> form of reimbursement such as waived charges for license maintenance or a 
> free toolbox) could be an option for the authors of high-quality FEX 
> submissions that fill a gap.
>
> Even something as simple (but non-intuitive) as Roger Stafford's 
> numerically robust method to calculate the angle between two 3D vectors 
> (angle = atan2(norm(cross(a,b)),dot(a,b))) would be a nice built-in 
> function.

Fwiw, does http://www.mathworks.com/help/techdoc/ref/subspace.html subspace 
calculate the angle you are looking for?

-- 
Loren
http://blogs.mathworks.com/loren/
http://www.mathworks.com/matlabcentral/newsreader/search_results?search_string=tag%3Afaq 

> 
> Fwiw, does http://www.mathworks.com/help/techdoc/ref/subspace.html subspace 
> calculate the angle you are looking for?
> 
> -- 
> Loren
> http://blogs.mathworks.com/loren/
> http://www.mathworks.com/matlabcentral/newsreader/search_results?search_string=tag%3Afaq 

I hadn't tried that before - the name 'subspace' doesn't bring that functionality to mind. But Roger's function is more accurate for small angles.

 a=[1 0 0]; b= [1 1e-10 0];

angle = atan2(norm(cross(a,b)),dot(a,b))*180/pi

angle =  5.729577951308232e-009

subspace(a,b)

ans =   0