Thread Subject: terminate function call in timer or button callback

hi all!

I'm having a GUI which calls a very computation and therefore also time intesnive function.
(See also http://www.mathworks.ch/matlabcentral/newsreader/view_thread/266103)
During this the calculation the user will be showed a progress bar with a cancel button,
since I don't know any way how to terminate this computation intensive function - which is "blocking" whole matlab except the callbacks - until now i do it like this:
when the user pushes the cancel button i change a flag which will be read every now and then by the calculation algorithm, which then aborts itself (by return) when the flag is set to "stop". (but this can be in worst case only every 100 seconds, which is a far too big latency from my point of view).

Is there a more sophisticated way to programatically terminate a running function called from a GUI within another GUI-element-callback????

Thanks 4 your help!
Fab