Documentation

This is the pseudo running mean class.

In order to calculate the "real" (mathematically correct) running mean value of a certain depth d, you will need to store the d most recent entries to the running mean. For large values of d, this can lead to excessive amount of memory allocated.

This pseudo running mean is an approximation of the running mean. It will work very well if you want to monitor values which don't vary too much, and makes it very well-suited for gain monitoring and similar applications, where there are no dramatic changes in the values under normal conditions. It will calculate the new running mean value rn from the existing value ro as

rn = ( ro * (d-1)/d + x ) /d

where x is the new value in the running mean calculation. If there have been less than d readings so far, it will return the actual mean value.

This class is mean to monitor lots of values (such as all channels of a given detector) simultaneously; In the cnstructor you specify the "width" (how many channels) and the depth of the running mean.

This class is meant to be lightweight, so there is not much in the way of bounds checking of the input data going on.

As a simple example, let's assume that you pre-select "laser trigger" events for the EmCal, and you want the running mean of the (144) channels calculated. You could construct a pseudoRunningMean object with 144 channels and depth 50:

 pseudoRunningMean *pm = new pseudoRunningMean(144,50);

and the pass your "laser" events and the pm object on to a routine that add the values:

int caculate_running_mean ( event * evt, RunningMean * rm)
{
   int array[144];
   Packet *p = evt->getPacket(8002);
   if (p) 
      {
          // yes, we got the packet, and we ask it now to get channel 57 for us
	  p->fillIntArray(array, 144, &nw);
          rm->Add(array);
	  delete p;
          return 0;
      }
   return 1;
}

Then, outside of your routine, you could ask the pm object for the (pseudo-) running mean value of channel i with

pm->getmean(i);

This class has no child classes.