I have a complex system of equations; when I try to find the answer Mathematica runs at full blast for an hour or so, but then the effort used by the program drops off to about 4% of CPU and just continues on that way. What's going on? Is Mathematica giving up on the problem? It doesn't give any indication that it has stopped working.
If it can't handle the calculation for lack of memory or CPU capacity, I need to know. What should I do?