xsh_eqwidth_lib.c

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#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
 
/*-----------------------------------------------------------------------------
                                   Includes
 -----------------------------------------------------------------------------*/
 
#include "xsh_eqwidth_lib.h"
#include <xsh_msg.h>
#include <gsl/gsl_version.h>
 
/*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
 
 
/*----------------------------------------------------------------------------*/
/*
  @brief    get index close to a given wavelenght in a table spectrum
  @param    spec_1d     spectrum table
  @param    lambda      wavelegth
  @return   return index (-1) if not valid????
 
        
  This function returns a the index of the closest wavelenght greatest than 
  lambda
-------------------------------------------------------------------------------*/
static cpl_size get_index_from_spec(cpl_table* spec_total, double lambda){
    //int* error=NULL;
    cpl_size index;
 
    /*
    double cdelta1=cpl_table_get(spec_total, "WAVEL",1, error) -
                      cpl_table_get(spec_total, "WAVEL",0, error);
    double crval1=cpl_table_get(spec_total, "WAVEL",0, error);
    */
    // Obsolete
    //index = (long) (1./cdelta1*lambda-crval1/cdelta1) + 1;
    // Correct formulae for velocity-binned spectra (TO BE USED FOR EFFICIENCY!?)
    //double dv = cdelta1 / crval1;
    //index     = (long)ceil(log(lambda / crval1) / dv);
 
    // Alternative instructions, using CPL functions
    cpl_table_unselect_all(spec_total);
    cpl_table_or_selected_double(spec_total, "WAVEL", CPL_NOT_GREATER_THAN,
                                 lambda);
    index = (int)cpl_table_count_selected(spec_total);
 
    if (index <= cpl_table_get_nrow(spec_total))
        {  return index; }
        else { return -1;}
}
 
 
#if 0
/* NOT USED ! */
static cpl_size get_index_from_spec_alt(cpl_table* spec_total, double lambda){
    int* error=NULL;
    cpl_size index;
    double cdelta1, crval1;
 
    cdelta1=cpl_table_get(spec_total, "WAVEL",1, error) - 
                      cpl_table_get(spec_total, "WAVEL",0, error);
 
    crval1=cpl_table_get(spec_total, "WAVEL",0, error);
    index = (long) (1./cdelta1*lambda-crval1/cdelta1) + 1;
 
// if spectra is binned in velocity 
    double dv = (cdelta1)/crval1;
    double r = 1.+dv;
    index = (long) log(lambda*r/cdelta1)/log(r);
 
// Python: math.log(ls*(1+dv/c)/ll[0])/math.log(r)
 
    if (index <= cpl_table_get_nrow(spec_total))
        {  return index; }
        else { return -1;}
}
#endif
 
 
 
/*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
 
static cpl_size get_pixel_to_nm_scale(cpl_table* spec_total, double nm){
    int* error=NULL;
    double cdelta1= cpl_table_get(spec_total, "WAVEL",1, error) - 
                      cpl_table_get(spec_total, "WAVEL",0, error);
    return nm/cdelta1;
}
 
/*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
 
 
cpl_error_code select_local_spec(cpl_table* spec_total,
                                  double ew_space,
                                  double lambda,
                                  cpl_table** spec_region)
{
    cpl_errorstate prestate = cpl_errorstate_get();
    //int* error = NULL;
 
 
 
    cpl_size index_line = get_index_from_spec(spec_total, lambda);
 
// 2* space is just a definition...
    cpl_size count = get_pixel_to_nm_scale(spec_total, 2 * ew_space);
    cpl_size begin = index_line - count/2;
 
 
    *spec_region = cpl_table_extract(spec_total,
                                     begin,
                                     count);
 
 
    if (!cpl_errorstate_is_equal(prestate)) {
        return (int)cpl_error_set_message(cpl_func, cpl_error_get_code(),
               "Unable to Get region of the spectrum");
    }
 
 
    return CPL_ERROR_NONE;
}
 
 
 
 
 
 
void find_left_right_continuum_pos(int* x1, int* x2, cpl_table* spec_region,double cont_rejt, double line){
 
 
 
// Interface from CPL tables to C arrays
    int i,n = cpl_table_get_nrow(spec_region);
    double x[n], y[n];
    for(i=0; i < n; i++){
        x[i] = cpl_table_get_double(spec_region,"WAVEL",i,NULL);
        y[i] = cpl_table_get_double(spec_region,"FLUX",i,NULL);
    }
 
 
// Code from ARES (could be improved
// It starts from the borders to the inside and check the continuum closest
// location to the line (Confuse but it works)
    int xind1=0,xind2=n-1,hjk;
    double klo=0.01; //Nm instead of Angstroms
    for (hjk=0; hjk < n; hjk++){
        if ((y[hjk] > cont_rejt) && 
            (x[hjk] - (line-klo) > x[xind1] - (line-klo)) && 
            (x[hjk] - (line-klo) < 0))
            xind1=hjk;
        if ((y[hjk] > cont_rejt) && 
            (x[hjk] - (line+klo) < x[xind2] - (line+klo)) && 
            (x[hjk] - (line+klo) > 0) )
            xind2=hjk;
    }
    *x1=xind1;
    *x2=xind2;
 
}
 
static cpl_table* esp_spec_deriv(cpl_table* spec_region){
 
// Interface from CPL tables to C arrays
    int i,n = cpl_table_get_nrow(spec_region);
    double x[n], y[n], dy[n];
 
    for(i=0; i < n; i++){
        x[i] = cpl_table_get_double(spec_region,"WAVEL",i,NULL);
        y[i] = cpl_table_get_double(spec_region,"FLUX",i,NULL);
    }
 
    cpl_table* table_deriv = NULL;  
    table_deriv = cpl_table_duplicate(spec_region);
 
    deriv(x,y,dy,n);
 
// Interface from c arrays to CPL Tables:
// Updating the spectral region
    for(i=0; i < n; i++){
        cpl_table_set_double(table_deriv,"FLUX",i,dy[i]);
    }
 
    return table_deriv;
}
 
 
static void esp_spec_smooth(cpl_table* spec_region, int smwidth){
 
// Interface from CPL tables to C arrays
    int i,n = cpl_table_get_nrow(spec_region);
    double y[n], sy[n];
    for(i=0; i < n; i++){
        y[i] = cpl_table_get_double(spec_region,"FLUX",i,NULL);
    }
 
    smooth(y, n, smwidth, sy);
 
// Interface from c arrays to CPL Tables:
// Updating the spectral region
    for(i=0; i < n; i++){
        cpl_table_set_double(spec_region,"FLUX",i,sy[i]);
    }
 
}
 
 
 
 
void smooth(double vec[], long n, int w, double svec[]) {
    int i,j;
    double soma;
 
    if (w%2 != 1)
            w++;
    for (i=0; (i < (w-1)/2);i++)
        svec[i]=vec[i];
    for (i=(w-1)/2;i<n-((w-1)/2);i++) {
        soma=0.;
        for (j=i-((w-1)/2); j<=i+((w-1)/2);j++)
            soma+=vec[j];
        svec[i]=soma/w;
    }
    for (i=n-((w-1)/2); i<n;i++)
        svec[i]=vec[i];
}
 
 
 
static void zeroscenterfind(double iy[], double y[], double dy[], double ddy[], long n, long center[], long *ncenter,double det_line_thres) {
    double maxdy;
    long ctot=0, i, centertot[n];
    int signalc=0, signalc_ant=0;
    if (ddy[0] == abs(ddy[0]))
        signalc=1;
    signalc_ant=signalc;
    maxdy=maxele_vec(dy,n);
 
    for (i=0; i<n; i++) {
        signalc=0;
        if ( (float) ddy[i] == fabs( (float) ddy[i]) )
            signalc=1;
        // EN: when the signal changes, the local maximum of the 2nd derivative 
        // is below the the noise, and the 3rd derivative is negative enough (due 
        // to noise)
        // EN: for the 0.98 the idea was to have the tree/rejt value, but it does not 
        // work so well. It identifies to many lines in cases of good S/N. This way
        // we only accept identified lines that have a depth of at least 0.98.
        // EN : The 3rd condition was hard codded as iy[i] < 0.98
        if ((signalc != signalc_ant) && 
             (dy[i] > 0.01*maxdy) && 
             (iy[i] < 1. - det_line_thres) && 
             (ddy[i] < -0.1)) {
            centertot[ctot]=i;
            ctot++;
        }
        signalc_ant=signalc;
    }
 
 
    if (ctot != 0) {
        *ncenter=ctot;
        for (i=0;i<ctot;i++)    center[i]=centertot[i];
    } else {
        center[0]=-1;
        *ncenter=0;
    }
}
 
 
double maxele_vec(double vec[], long nvec) {
    long i;
    double maxi=vec[1+nvec/20];
    for (i=1+nvec/20; i<nvec-nvec/20; i++)
        maxi = max(maxi,vec[i]);
    return maxi;
}
 
 
// NEEDS GSL:::
 
 
/*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
 
cpl_error_code esp_fit_ngauss(cpl_table* spec_cont_region, 
                              cpl_table* line_table,
                              double fit_ngauss_width)
{
 
    cpl_errorstate prestate = cpl_errorstate_get();
 
 
// Interface from CPL tables to C arrays
    int i,ns = cpl_table_get_nrow(spec_cont_region);
    int nl = cpl_table_get_nrow(line_table);
 
    double xfit[ns], yfit[ns], sigma[ns];
 
    for(i=0; i < ns; i++){
        xfit[i] = cpl_table_get_double(spec_cont_region,"WAVEL",i,NULL);
        yfit[i] = cpl_table_get_double(spec_cont_region,"FLUX",i,NULL) - 1.0;
//        sigma[i] = cpl_table_get_double(spec_cont_region,"FLUXERR",i,NULL);
//  One good approximation for testing purposes is 1.-cont_rejt
        sigma[i] = 1.- 0.997573;
    }
 
    int npara=3*nl;
    int igauss=0;
    double acoef[npara], acoef_er[npara];
    for (i=0;i<nl;i++) {
        acoef[3*igauss]=cpl_table_get_double(line_table,"PEAK",i,NULL) - 1.0;
// CAREFUL here with this guess value
        acoef[3*igauss+1]=fit_ngauss_width;
        acoef[3*igauss+2]=cpl_table_get_double(line_table,"WAVEL",i,NULL);
        igauss++;
    }
 
    int status2;
    
    fitngauss(xfit,yfit,sigma,ns,acoef,acoef_er,npara,&status2);
 
// We probably need to control here the sucess of the fitting...
 
// Interface from c arrays to CPL Tables:
// Updating the spectral region
    for(i=0; i < nl; i++){
        cpl_table_set_double(line_table,"PEAK",i,-acoef[3*i]);
        cpl_table_set_double(line_table,"PEAK_ERR",i,acoef_er[3*i]);
        cpl_table_set_double(line_table,"WAVEL",i,acoef[3*i+2]);
        cpl_table_set_double(line_table,"WAVEL_ERR",i,acoef_er[3*i+2]);
// FWHM for the defined Gaussian (ARES): F(X)=Aexp(-Lambda(x-c)^2) => FWHM=2*sqrt(ln(2)/lambda)
        cpl_table_set_double(line_table,"FWHM",i,2.*sqrt(log(2)/acoef[3*i+1]));
        double ind_ew = acoef[3*i]*sqrt(CPL_MATH_PI/acoef[3*i+1])*-1.;
        cpl_table_set_double(line_table,"EW",i,ind_ew*10000.);
        cpl_table_set_double(line_table,"SIGMA",i,sqrt(0.5/(acoef[3*i+1])));
        cpl_table_set_double(line_table,"SIGMA_ERR",i,0.5*CPL_MATH_SQRT1_2*(acoef_er[3*i+1])*pow(acoef[3*i+1],-3.*0.5));        
// using error equation propagation
//    medida_er_square+=medida*medida * ( acoef_er[3*hj]*acoef_er[3*hj]/acoef[3*hj]/acoef[3*hj] + (0.5*0.5*acoef_er[3*hj+1]*acoef_er[3*hj+1]/acoef[3*hj+1]/acoef[3*hj+1]));
//        printf("medida: %15.10lf\n", ind_ew);
        double ind_ew_err_square = ind_ew*ind_ew * ( acoef_er[3*i]*acoef_er[3*i]/acoef[3*i]/acoef[3*i] + (0.5*0.5*acoef_er[3*i+1]*acoef_er[3*i+1]/acoef[3*i+1]/acoef[3*i+1]));
        cpl_table_set_double(line_table,"EW_ERR",i,sqrt(ind_ew_err_square)*10000.);
    }
 
 
    if (!cpl_errorstate_is_equal(prestate)) {
        return (int)cpl_error_set_message(cpl_func, cpl_error_get_code(),
               "Unable to Get region of the spectrum");
    }
 
 
    return CPL_ERROR_NONE;
 
}
 
 
double check_ew(cpl_table* line_table,
                double line,
                double det_line_resol,
                int* index_line,
                int* n_lines,
                double* ew_error){
 
    int nl = cpl_table_get_nrow(line_table);
 
    double ew=0.;
    double ew_er=0.;
    int i;
    
    *index_line = 0;
    *n_lines=0;
 
    for (i=0; i < nl; i++) {
        if ( fabs( line - cpl_table_get_double(line_table,"WAVEL",i,NULL) ) < det_line_resol ) {
            ew+=cpl_table_get_double(line_table,"EW",i,NULL);
            ew_er+=cpl_table_get_double(line_table,"EW_ERR",i,NULL);
            (*n_lines)++;
            *index_line=i;
        }
    }
    *ew_error=ew_er;
 
    return ew;
}
 
 
 
static void
poly_fitn(double xvec[], double yvec[], double err[], long n, long ord, double coefs[]) {
    int i, j, k;
    double xi, yi, ei, chisq,xi2;
    gsl_matrix *X, *cov;
    gsl_vector *y, *w, *c;
    ord++;
    X = gsl_matrix_alloc (n, ord);
    y = gsl_vector_alloc (n);
    w = gsl_vector_alloc (n);
    c = gsl_vector_alloc (ord);
    cov = gsl_matrix_alloc (ord, ord);
    for (i = 0; i < n; i++) {
      xi=xvec[i];
      yi=yvec[i];
      ei=err[i];
      for (j = 0; j < ord; j++) {
        xi2=1.0;
        for (k=0; k<j; k++) xi2*=xi;
        gsl_matrix_set (X, i, j, xi2);
        }
      gsl_vector_set (y, i, yi);
      gsl_vector_set (w, i, 1.0/(ei*ei));
    }
 
    gsl_multifit_linear_workspace * work = gsl_multifit_linear_alloc (n, ord);
    gsl_multifit_wlinear (X, w, y, c, cov, &chisq, work);
    gsl_multifit_linear_free (work);
 
    #define C(i) (gsl_vector_get(c,(i)))
    #define COV(i,j) (gsl_matrix_get(cov,(i),(j)))
 
    for (j = 0; j < ord; j++)
        coefs[j]=C(j);
    gsl_vector_free (y);
    gsl_vector_free (w);
    gsl_vector_free (c);
    gsl_matrix_free (X);
    gsl_matrix_free (cov);
    
}
 
void deriv(double x[], double y[], double dy[], long n) {
    int i;
    gsl_interp_accel *acc = gsl_interp_accel_alloc ();
    gsl_interp *interp = gsl_interp_alloc (gsl_interp_cspline, n);
    //gsl_interp *interp = gsl_interp_alloc (gsl_interp_akima, n);
 
    gsl_interp_init (interp, x, y, n);
    for (i=0; i<n; i++)
        dy[i]=gsl_interp_eval_deriv (interp, x, y,x[i],acc);
    gsl_interp_free (interp);
    gsl_interp_accel_free (acc);
}
 
 
void fitngauss(double t[], double y[], double sigma[], long nvec, 
               double acoef[], double acoef_er[], int para, int *status2)
{
  const gsl_multifit_fdfsolver_type *T;
  gsl_multifit_fdfsolver *s;
 
  int status;
  size_t i, iter = 0;
  long N=nvec;
  const size_t n = N;
  const size_t p = para;
 
  gsl_matrix *covar = gsl_matrix_alloc (p, p);
#if defined GSL_MAJOR_VERSION && GSL_MAJOR_VERSION >= 2
  gsl_matrix *J;
#endif
//  double dy[N];
  struct data d = { n, para, t, y, sigma};
  gsl_multifit_function_fdf f;
 
  double x_init[para];
  for (i=0; i< (size_t) para; i++)
    x_init[i]=acoef[i];
 
  f.f = &expb_f;
  f.df = &expb_df;
  f.fdf = &expb_fdf;
  f.n = n;
  f.p = p;
  f.params = &d;
 
  gsl_vector_view x = gsl_vector_view_array (x_init, p);
 
  T = gsl_multifit_fdfsolver_lmder;
 
  s = gsl_multifit_fdfsolver_alloc (T, n, p);
 
  gsl_multifit_fdfsolver_set (s, &f, &x.vector);
  do
    {
      iter++;
      status = gsl_multifit_fdfsolver_iterate (s);
 
//      int i=0;
      if (status)
        break;
 
      status = gsl_multifit_test_delta (s->dx, s->x,
                                        1e-6, 1e-6);
    }
  while (status == GSL_CONTINUE && iter < 5000);
#if defined GSL_MAJOR_VERSION && GSL_MAJOR_VERSION >= 2
  J = gsl_matrix_alloc(n, p);
  gsl_multifit_fdfsolver_jac(s, J);
  gsl_multifit_covar (J, 0.0, covar);
  gsl_matrix_free (J);
#else
  gsl_multifit_covar (s->J, 0.0, covar);
#endif
 
#define FIT(i) gsl_vector_get(s->x, i)
#define ERR(i) sqrt(gsl_matrix_get(covar,i,i))
 
  {
 
    double chi = gsl_blas_dnrm2(s->f);
    double dof = n - p;
    double c = GSL_MAX_DBL(1, chi / sqrt(dof));
 
    for (i=0; i < (size_t) para; i++)
    {
        acoef[i]=FIT(i);
        acoef_er[i]=c*ERR(i);
    }
 
  *status2=status;
  *status2=0;   //sometimes we have bad fits but the result is perfectably acceptable
  }
  gsl_multifit_fdfsolver_free (s);
  gsl_matrix_free (covar);
}
 
 
// TO BE Located in another file:
 
 
/*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
 
cpl_error_code espda_create_line_table(cpl_table **tab,
                                       cpl_size    size) 
 
{
    cpl_errorstate prestate = cpl_errorstate_get();
    cpl_size       ceil;
 
/*
 * Table of given row size is created. Columns are those specified for the 
 * structure SPEC.
 */
 
    *tab = cpl_table_new(size);
    cpl_table_new_column(*tab, "WAVEL",      CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "WAVEL_ERR",  CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "PEAK",       CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "PEAK_ERR",   CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "MU",         CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "MU_ERR",     CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "SIGMA",      CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "SIGMA_ERR",  CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "EW",         CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "EW_ERR",     CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "FWHM",       CPL_TYPE_DOUBLE);
    cpl_table_new_column(*tab, "FWHM_ERR",   CPL_TYPE_DOUBLE);
 
    if (!cpl_errorstate_is_equal(prestate)) {
        return (int)cpl_error_set_message(cpl_func, cpl_error_get_code(),
               "Unable to create table.");
    }
 
/*
 * Columns are initialized with default values.
 */
 
    if (size > 0) {
        ceil = size;
    }
    else {
        ceil = 0;
    }
    cpl_table_fill_column_window_double(*tab, "WAVEL",     0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "WAVEL_ERR", 0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "PEAK",      0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "PEAK_ERR",  0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "MU",        0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "MU_ERR",    0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "SIGMA",     0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "SIGMA_ERR", 0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "EW",        0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "EW_ERR",    0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "FWHM",      0, ceil, -9999.0);
    cpl_table_fill_column_window_double(*tab, "FWHM_ERR",  0, ceil, -9999.0);
 
    if (!cpl_errorstate_is_equal(prestate)) {
        return (int)cpl_error_set_message(cpl_func, cpl_error_get_code(),
               "Unable to initialize table.");
    }
 
/* 
 * The new table is passed along. 
 */
 
    return CPL_ERROR_NONE;
}
 
/*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
 
 
cpl_error_code esp_fit_lcont(cpl_table* spec_region,
                             double cont_rejt,
                             int cont_iter){
 
    cpl_errorstate prestate = cpl_errorstate_get();
 
    int n = cpl_table_get_nrow(spec_region);
 
 
    int order,i,j;
    order=2;
    double coefs[order+1];
    double x[n], y[n], err[n], ynorm[n];
    long nvec;
 
 
// Interface from CPL tables to C arrays
    for(i=0; i < n; i++){
        x[i] = cpl_table_get_double(spec_region,"WAVEL",i,NULL);
        y[i] = cpl_table_get_double(spec_region,"FLUX",i,NULL);
//        err[i] = cpl_table_get_double(spec_region,"FLUXERR",i,NULL);
        err[i] = 1.0;
    }
 
 
// Calling ARES routines and code (continuum_det5)
 
    poly_fitn(x,y,err,n,order,coefs);
 
// Creation of the array with the values of the polynomial
    double xi=1.;
    for(i=0; i < n; i++) {
        ynorm[i]=0.;
        xi=1.;
        for (j=0; j < order + 1; j++) {
            ynorm[i]+=coefs[j]*xi;
            xi*=x[i];
        }
    }
 
    double vecx[n],vecy[n];
    int jk;
    for (jk=0; jk < cont_iter; jk++) {
        nvec=0;
// Selection of the points for the next fit
        for (i=0; i<n-1; i++) {
//This was to try to avoid cosmic rays, although does not works well always.
// original comment: test were made with 0.01, there should not be any problem to put it larger. I choosed 0.1 in ARES
 
            if (y[i] > ynorm[i]*cont_rejt && fabs(y[i]-y[i+1]) < 0.1*y[i]){
                vecx[nvec]=x[i];
                vecy[nvec]=y[i];
                nvec++;
            }
        }
        poly_fitn(vecx,vecy,err,nvec,order,coefs);
 
        for(i=0; i < n; i++) {
            ynorm[i]=0.;
            xi=1.;
            for (j=0;j<order+1;j++) {
                ynorm[i]+=coefs[j]*xi;
                xi*=x[i];
            }
        }
    }
 
// normalization
    for (i=0; i < n; i++)
        ynorm[i]=y[i]/(coefs[0]+coefs[1]*x[i]+coefs[2]*x[i]*x[i]);
 
// Interface from c arrays to CPL Tables:
// Updating the spectral region
    for(i=0; i < n; i++){
        cpl_table_set_double(spec_region,"FLUX",i,ynorm[i]);
    }
 
    if (!cpl_errorstate_is_equal(prestate)) {
        return (int)cpl_error_set_message(cpl_func, cpl_error_get_code(),
               "Unable to Get region of the spectrum");
    }
 
 
    return CPL_ERROR_NONE;
}
 
 
 
/*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------*/
 
cpl_error_code esp_det_line(cpl_table* spec_cont_region,
                            double det_line_thres,
                            double det_line_resol,
                            int det_line_smwidth,
                            cpl_table** line_table
                            ){
 
    cpl_errorstate prestate = cpl_errorstate_get();
 
 
    cpl_table* spec_cont_region_der1 = NULL;
    cpl_table* spec_cont_region_der2 = NULL;
    cpl_table* spec_cont_region_der3 = NULL;
 
    spec_cont_region_der1 = esp_spec_deriv(spec_cont_region);
 
    esp_spec_smooth(spec_cont_region_der1, det_line_smwidth);
 
    spec_cont_region_der2 = esp_spec_deriv(spec_cont_region_der1);
    esp_spec_smooth(spec_cont_region_der2, det_line_smwidth);
 
    spec_cont_region_der3 = esp_spec_deriv(spec_cont_region_der2);
    esp_spec_smooth(spec_cont_region_der3, det_line_smwidth);
 
 
// Interface from CPL tables to C arrays
    int i,n = cpl_table_get_nrow(spec_cont_region);
    double x[n], iy[n], y[n], dy[n], ddy[n];
    for(i=0; i < n; i++){
        x[i] = cpl_table_get_double(spec_cont_region,"WAVEL",i,NULL);
        iy[i] = cpl_table_get_double(spec_cont_region,"FLUX",i,NULL);
        y[i] = cpl_table_get_double(spec_cont_region_der1,"FLUX",i,NULL);
        dy[i] = cpl_table_get_double(spec_cont_region_der2,"FLUX",i,NULL);
        ddy[i] = cpl_table_get_double(spec_cont_region_der3,"FLUX",i,NULL);
    }
 
    cpl_table_delete(spec_cont_region_der1);
    cpl_table_delete(spec_cont_region_der2);
    cpl_table_delete(spec_cont_region_der3);
 
    long ncenter=n, center[n];
 
//  this obtains the indexes close to the lines center
    zeroscenterfind(iy, y, dy, ddy, n, center, &ncenter,det_line_thres);
 
//  calculating/interpolating the position of the center of the lines in the spectra:
//  Maybe this is not necessary...
 
// Only if lines were detected
    if (center[0] != -1 && ncenter != 0) {
        double xlinhas[ncenter], ylinhas[ncenter];
        int i1,i1m;
        double den, diff_y;
 
        for (i=0; i<ncenter; i++) {
            i1=center[i];
            i1m=i1-1;
            den=1./(x[i1]-x[i1-1]);
            diff_y=(ddy[i1] - ddy[i1m]);
            xlinhas[i]= ( -ddy[i1m] + diff_y*den * x[i1] )  / ( diff_y*den );
            ylinhas[i]= diff_y*den * xlinhas[i] + iy[i1m] - ( iy[i1]- iy[i1m] )*den * x[i1] ;
        }
 
 
//RESAMPLING, Negleting "lines" that are to close to each other (noisy lines)
        double xvec2[ncenter], yvec2[ncenter];
        int nvec2,j;
        xvec2[0]=xlinhas[0];
        yvec2[0]=ylinhas[0];
        j=0;
        for(i=1;i<ncenter;i++) {
            if (fabs(xvec2[j]-xlinhas[i]) < det_line_resol ) {
                xvec2[j]=(xvec2[j]+xlinhas[i])*0.5;
                yvec2[j]=(yvec2[j]+ylinhas[i])*0.5;
            } else {
                j++;
                xvec2[j]=xlinhas[i];
                yvec2[j]=ylinhas[i];
            }
        }
        nvec2=j+1;
 
 
// Interface C arrays to CPL Table
// Creating and filling the line table
 
        cpl_ensure_code(espda_create_line_table(line_table,
                                                nvec2)
                        == CPL_ERROR_NONE, cpl_error_get_code());
 
        for (i=0; i<nvec2; i++) {
            cpl_table_set_double(*line_table,"WAVEL",i,xvec2[i]);
            cpl_table_set_double(*line_table,"PEAK",i,yvec2[i]);
        }
// If no lines are detected then we create a line table without rows
    } else {
        int nvec2=0;
        cpl_ensure_code(espda_create_line_table(line_table,
                                                nvec2)
                        == CPL_ERROR_NONE, cpl_error_get_code());
 
    }
 
 
    if (!cpl_errorstate_is_equal(prestate)) {
        return (int)cpl_error_set_message(cpl_func, cpl_error_get_code(),
               "Unable to Get region of the spectrum");
    }
 
 
    return CPL_ERROR_NONE;
}