average timespecs

[rszymanski]

I have a stl vector of timespecs and need to determine the average of the timespecs. The size of the vector wont be any larger than 5k.

What I have doesn't seem to work quite right. I'm thinking the data types may be rolling over. Anyone got any ideas?

static unsigned long CalculateAvg(vector<timespec> *pvecResults){
	timespec sumTime;
	unsigned long ulAvgNs = 0;
	unsigned long ultotalNs = 0;

	try
	{
		// Build up the result statistics.  First we need the sum the execTimes of each call
		for(vector<timespec>::iterator vecResultsIterator = pvecResults->begin();
				                       vecResultsIterator != pvecResults->end();
			                           vecResultsIterator++)
		{
			sumTime = tsAdd(sumTime,(timespec)*vecResultsIterator);
		}

		// then convert sumTime to nanoseconds
		ultotalNs = sumTime.tv_sec * NSEC_PER_SEC + sumTime.tv_nsec;

		// Then calculate the average nanoseconds/session
	    ulAvgNs = ultotalNs / pvecResults->size();
	}
	catch(...)
	{
		cout << "Error calculating average" << endl;
	}

	return ulAvgNs;
}

[shacktar]

How about just adding the nanoseconds instead of the timespecs?

unsigned long ulAvgNs = 0;
unsigned long ultotalNS = 0;

for(vector<timespec>::iterator vecResultsIterator = pvecResults->begin(); 
     vecResultsIterator != pvecResults->end(); vecResultsIterator++)
{
     ultotalNS  += vecResultsIterator->tv_sec * NSEC_PER_SEC + vecResultsIterator->tv_nsec;
}

ulAvgNs = ultotalNs / pvecResults->size();

[Galik]

You don't appear to initialize sumTime.