When I ran the code you posted, the while loop becomes infinite if ‘min(DPnew)’ is negative. In that event, this expression:
appears to increase until it reaches a value of about 3. (I don’t know if it increases beyond that, since I interrupted it before then.)
Trapping negative values of ‘DPnew’ and correcting them, or setting an additional limit on the while condition (for example, adding a counter and setting the additional while condition that the counter does not exceed some value), should solve that problem, or at least prevent the loop from becoming infinite.
I doubt MATLAB is pausing to debug the code.