[lakeat]

Dear all,

A small question, what is the difference between "ExecutionTime" and "ClockTime"?

I can get these lins from icoFoam.C,

Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
<< " ClockTime = " << runTime.elapsedClockTime() << " s"
<< nl << endl;

someone said:

elapsedCPUTime() is the elapsed CPU time.
elapsedClockTime() is the elapsed wall clock time.

1. Could anyone explain this in detail?
2. If ClockTime means something, why then that we have to care about ExecutionTime?
3. Is there any meaning concerning the ratio of ClockTime over ExecutionTime? Latency, or what?
4. How can I change the writing format of these time, eg. show four decimal places in second.?

Thanks in advance for any reply.