bpmprocess/get_pedestal.c

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#include <math.h>

#include <bpm/bpm_messages.h>
#include <bpm/bpm_process.h>

int get_pedestal( int *wf, int ns, int range, double *offset, double *rms ) {
  

  double avg = 0., sqr_sum = 0.;
  int i;

  if ( ! wf || ! offset ) {
    bpm_error( "Invalid pointer argument in get_pedestal(...)",
               __FILE__, __LINE__ );
    return BPM_FAILURE;
  }
  
  if ( range == 0 || ns == 0 ) {
    bpm_error("Maximum range or number of samples equal zero in get_pedestal(...)",
              __FILE__, __LINE__ );
    return BPM_FAILURE;
  }

  if ( ns < range ) {
    bpm_warning("Number of samples < max range in get_pedestal(...)", 
                __FILE__, __LINE__ );
    range = ns;
  }
  
  // find the mean and keep track of sum of squares
  for ( i = 0; i < range; i++) {
    avg     += (double) wf[i];
    sqr_sum += (double) wf[i]*wf[i];
  }

  *offset = avg / (double) range;
  if ( rms ) {
    *rms = sqrt( sqr_sum / (double) range - SQR( *offset ) );
  } else {
    bpm_warning( "NULL pointer given for rms in get_pedestal(...)",
                 __FILE__, __LINE__ );
  }

  return BPM_SUCCESS;
}

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