TSFit.cc

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/* 
 *  \class TSFit
 *
 *  \author: Jean-Pierre Pansart - CEA/Saclay
 */

#include <CalibCalorimetry/EcalLaserAnalyzer/interface/TSFit.h>

#include <cstdio>
#include <cmath>
#include <cstring>

//ClassImp(TSFit)

//------------------------------------------------------------------------
// TSFit provide fitting methods of pulses with third degree polynomial
//

TSFit::TSFit(int size, int size_sh) {
  sdim = size;
  plshdim = size_sh;
  // sample_flag = new int[size];
  //   t = new double[sdim];
  //   z = new double[sdim];
  //   f = new double[sdim];
  //   acc = new double[sdim];
  //   adfmx = new double[sdim];
  //   adcp = new double[sdim];
  //   maskp3 = new double[sdim];
  //   corel = new double[sdim];
  //   nbcor = new double[sdim];
  //   int k;
  //   ff = new double *[sdim];
  //   for(k=0;k<sdim;k++)ff[k] = new double[4];
  //   der = new double *[sdim];
  //   for(k=0;k<sdim;k++)der[k] = new double[5];
}

void TSFit::set_params(int n_samples,
                       int niter,
                       int n_presmpl,
                       int sample_min,
                       int sample_max,
                       double time_of_max,
                       double chi2_max,
                       int nsbm,
                       int nsam) {
  // parameters initialisation of the fit package
  // nsbm  n_samples_bef_max, nsam n_samples_aft_max

  nbs = n_samples;
  nbr_iter_fit = niter;
  n_presamples = n_presmpl;
  iinf = sample_min;
  isup = sample_max;
  avtm = time_of_max;
  xki2_max = chi2_max;
  n_samples_bef_max = nsbm;
  n_samples_aft_max = nsam;

  norme = 0.;
  alpha_th = 2.20;
  beta_th = 1.11;

  int k;

  for (k = 0; k <= nbs; k++) {
    sample_flag[k] = 0;
  }

  for (k = sample_min; k <= sample_max; k++) {
    sample_flag[k] = 1;
  }
  /*
  int lim1 = ( iinf > n_presamples ) ? n_presamples : iinf;
  for(int k=lim1;k<=sample_max;k++){
    sample_flag[k] = 2;
  }
  */
  //  printf( "sample_fag : " );
  //   for(k=0;k<=nbs;k++){
  //     printf( "%1d ", sample_flag[k] );
  //   }
  //   printf( "\n" );
}

void TSFit::init_errmat(double noise_initialvalue) {
  //  Input:  noise_initial value  noise (in adc channels) as read in the
  //  data base.
  /*------------------------------------------------------------------------*/

  int i, j;
  //double one_over_noisesq;

  //one_over_noisesq = 1. / ( noise_initialvalue * noise_initialvalue );
  for (i = 0; i < sdim; i++) {
    for (j = 0; j < sdim; j++) {
      errmat[i][j] = noise_initialvalue;
      //errmat[i][j] = 0.;
    }
    //errmat[i][i] = one_over_noisesq;
  }
}

double TSFit::fpol3dg(int nmxul, double *parom, double *mask, double *adc) {
  // fit third degree polynomial
  // nmxul   array adc[] length
  // parom   return parameters (a0,a1,a2,a3,pos max,height)
  // fplo3dg uses only the diagonal terms of errmat[][]
  // errmat  inverse of the error matrix

  int i, k, l;
  double h, t2, tm, delta, tmp;
  double xki2, dif, difmx, deglib;
  double bv[4], s;

  deglib = (double)nmxul - 4.;
  for (i = 0; i < nmxul; i++) {
    t[i] = i;
    ff[i][0] = 1.;
    ff[i][1] = t[i];
    ff[i][2] = t[i] * t[i];
    ff[i][3] = ff[i][2] * t[i];
  }
  /*   computation of covariance matrix     */
  for (k = 0; k < 4; k++) {
    for (l = 0; l < 4; l++) {
      s = 0.;
      for (i = 0; i < nmxul; i++) {
        s = s + ff[i][k] * ff[i][l] * errmat[i][i] * mask[i];
      }
      cov[k][l] = s;
    }
    s = 0.;
    for (i = 0; i < nmxul; i++) {
      s = s + ff[i][k] * adc[i] * errmat[i][i] * mask[i];
    }
    bv[k] = s;
  }
  /*     parameters                          */
  inverms(4, cov, invcov);
  for (k = 0; k < 4; k++) {
    s = 0.;
    for (l = 0; l < 4; l++) {
      s = s + bv[l] * invcov[l][k];
    }
    parom[k] = s;
  }

  if (parom[3] == 0.) {
    parom[4] = -1000.;
    parom[5] = -1000.;
    parom[6] = -1000.;
    return 1000000.;
  }
  /*    worst hit and ki2                    */
  xki2 = 0.;
  difmx = 0.;
  for (i = 0; i < nmxul; i++) {
    t2 = t[i] * t[i];
    h = parom[0] + parom[1] * t[i] + parom[2] * t2 + parom[3] * t2 * t[i];
    dif = (adc[i] - h) * mask[i];
    xki2 = xki2 + dif * dif * errmat[i][i];
    if (dif > difmx) {
      difmx = dif;
    }
  }
  if (deglib > 0.5)
    xki2 = xki2 / deglib;
  /*     amplitude and maximum position                    */
  delta = parom[2] * parom[2] - 3. * parom[3] * parom[1];
  if (delta > 0.) {
    delta = sqrt(delta);
    tm = -(delta + parom[2]) / (3. * parom[3]);
    tmp = (delta - parom[2]) / (3. * parom[3]);
  } else {
    parom[4] = -1000.;
    parom[5] = -1000.;
    parom[6] = -1000.;
    return xki2;
  }
  parom[4] = tm;
  parom[5] = parom[0] + parom[1] * tm + parom[2] * tm * tm + parom[3] * tm * tm * tm;
  parom[6] = tmp;
  return xki2;
}
double TSFit::inverms(int n, double g[matdim][matdim], double ginv[matdim][matdim]) {
  // inversion of a positive definite symetric matrix of size n

  int i, j, k, jj;
  double r, s;
  double deter = 0;

  /*   initialisation  */

  if (n > matdim) {
    printf("ERROR : trying to use TSFit::inverms with size %d( max allowed %d\n", n, matdim);
    return -999.;
  }

  int zero = 0;
  memset((char *)al, zero, 8 * n * n);
  memset((char *)be, zero, 8 * n * n);
  /*
  for(i=0;i<n;i++){
    for(j=0;j<n;j++){
      al[i][j] = 0.;
      be[i][j] = 0.;
    }
  }
  */
  /*  decomposition en vecteurs sur une base orthonormee  */
  al[0][0] = sqrt(g[0][0]);
  for (i = 1; i < n; i++) {
    al[i][0] = g[0][i] / al[0][0];
    for (j = 1; j <= i; j++) {
      s = 0.;
      for (k = 0; k <= j - 1; k++) {
        s = s + al[i][k] * al[j][k];
      }
      r = g[i][j] - s;
      if (j < i)
        al[i][j] = r / al[j][j];
      if (j == i)
        al[i][j] = sqrt(r);
    }
  }
  /*  inversion de la matrice al   */
  be[0][0] = 1. / al[0][0];
  for (i = 1; i < n; i++) {
    be[i][i] = 1. / al[i][i];
    for (j = 0; j < i; j++) {
      jj = i - j - 1;
      s = 0.;
      for (k = jj + 1; k <= i; k++) {
        s = s + be[i][k] * al[k][jj];
      }
      be[i][jj] = -s / al[jj][jj];
    }
  }
  /*   calcul de la matrice ginv   */
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
      s = 0.;
      for (k = 0; k < n; k++) {
        s = s + be[k][i] * be[k][j];
      }
      ginv[i][j] = s;
    }
  }

  return deter;
}

double TSFit::fit_third_degree_polynomial(double *bdc, double *ret_dat) {
  //  third degree polynomial fit of the pulse summit.
  //  samples are contained in array bdc and must be pedestal
  //  substracted.
  //  only samples having sample_flag >= 1 are used.
  //  the unit of time is one clock unit, that is to say 25 ns.
  //  output: ret_dat[0] = pulse height
  //          ret_dat[1]   position of maximum in the sample frame in clock units
  //          ret_dat[2]   adc value of the highest sample
  //          ret_dat[3]   number of the highest sample
  //          ret_dat[4]   lower sample number used for fitting
  //          ret_dat[5]   upper sample number used for fitting
  // errmat  inverse of the error matrix

  int i;
  int nus;
  double xki2;
  double tm, tmp, amp;

  ret_dat[0] = -999.;
  ret_dat[1] = -999.;

  //    search the maximum
  double val_max = 0.;
  int imax = 0;
  for (i = 0; i < nbs; i++) {
    if (sample_flag[i] == 0)
      continue;
    if (bdc[i] > val_max) {
      val_max = bdc[i];
      imax = i;
    }
  }

  if ((val_max * val_max) * errmat[imax][imax] < 16.)
    return -118;

  //  if( imax != 9 )printf( "imax : %d !!!!!!!!!!!!!!!!!!!!!!!!!!!\n", imax );

  if (norme == 0.)
    norme = val_max;

  // look for samples above 1/3 of maximum before and 1/2 after
  double val2 = val_max / 2.;
  double val3 = val_max / 2.;
  int ilow = iinf;
  int ihig = 0;

  for (i = iinf; i <= isup; i++) {
    if (sample_flag[i] >= 1) {
      if ((bdc[i] < val3) && (i < imax))
        ilow = i;
      if (bdc[i] > val2)
        ihig = i;
    }
  }

  ilow++;

  //ilow = imax - 1;

  /*  le test suivant, apparemment idiot, est mis a cause des sequences 0. 2048. qui apparaissent dans certains mauvais evts     JPP 11/09/00 */

  if (ihig == ilow)
    return -105;
  if (ilow == imax)
    ilow = ilow - 1;
  //if( ihig - ilow < 3 )ihig = ilow + 3;
  ihig = ilow + 3;

  /*   printf("  third degree:   ilow %d ihig %d \n",ilow,ihig);  */
  nus = 0;
  int number_of_good_samples = 0;
  for (i = ilow; i <= ihig; i++) {
    maskp3[nus] = 0;
    adfmx[nus] = 0.;
    /*    printf(" adc %f sample_flag %d number_of good_samples %d \n",bdc[i],sample_flag[i],number_of_good_samples);  */
    if (sample_flag[i] >= 1) {
      adfmx[nus] = bdc[i];
      maskp3[nus] = 1.;
      number_of_good_samples++;
    }
    nus++;
  }

  if (number_of_good_samples < 4) {
    return (-106);
  }

  xki2 = fpol3dg(nus, &parfp3[0], &maskp3[0], &adfmx[0]);

  /* printf( "fpol3dg-----------------------------------> %f %f %f %f %f\n",
      parfp3[0], parfp3[1], parfp3[2], parfp3[3], parfp3[4] );  */

  tm = parfp3[4] + (float)ilow;
  amp = parfp3[5];

  if (amp * amp * errmat[0][0] < 2.)
    return -101.;
  tmp = parfp3[6] + (float)ilow;

  /*
    validation of fit quality.  Most of the time the fit is done with
    four samples, therefore there is no possible ki2 check. When more than
    4 samples are used the ki2 is often bad. So, in order to suppress some 
    events with bad samples, a consistency check on the position of the
    maximum and minimum of the 3rd degree polynomial is used.
  */

  if (xki2 > xki2_max) {
    return -102.;
  }
  if ((tm < (double)ilow) || (tm > (double)ihig)) {
    return -103.;
  }

  if ((tmp > (double)ilow) && (tmp < (double)ihig - 1.)) {
    return -104.;
  }

  ret_dat[0] = amp;
  ret_dat[1] = tm;
  ret_dat[2] = val_max;
  ret_dat[3] = (double)imax;
  ret_dat[4] = (double)ilow;
  ret_dat[5] = (double)ihig;
  ret_dat[6] = (double)tmp;
  int k;
  for (i = 0; i < 4; i++) {
    k = i + 7;
    ret_dat[k] = parfp3[i];
  }

  return xki2;
}