ObsLocGC99.cc

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/*
 * (C) Copyright 2020-2021 UCAR
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 */
 
#include "lorenz95/ObsLocGC99.h"
 
#include <algorithm>
#include <cmath>
#include <vector>
 
#include "eckit/config/Configuration.h"
#include "eckit/geometry/Point2.h"
 
#include "lorenz95/Iterator.h"
#include "lorenz95/L95Traits.h"
#include "lorenz95/ObsTable.h"
#include "lorenz95/ObsVec1D.h"
 
#include "oops/generic/gc99.h"
 
// -----------------------------------------------------------------------------
namespace lorenz95 {
 
static oops::ObsLocalizationMaker<L95Traits, L95ObsTraits, ObsLocGC99> makerGC_("Gaspari-Cohn");
 
// -----------------------------------------------------------------------------
 
ObsLocGC99::ObsLocGC99(const eckit::Configuration & config, const ObsTable & obsdb)
  : rscale_(config.getDouble("lengthscale")), obsdb_(obsdb)
{
}
 
// -----------------------------------------------------------------------------
 
void ObsLocGC99::computeLocalization(const Iterator & iterator, ObsVec1D & locfactor) const {
  std::vector<double> locations = obsdb_.locations();
  eckit::geometry::Point2 center = *iterator;
  for (unsigned int ii=0; ii < obsdb_.nobs(); ++ii) {
    double curdist = std::abs(center[0] - locations[ii]);
    curdist = std::min(curdist, 1.-curdist);
    if (curdist >= rscale_) {
      locfactor[ii] = locfactor.missing();
    } else {
      locfactor[ii] = oops::gc99(curdist/rscale_);
    }
  }
}
 
// -----------------------------------------------------------------------------
 
void ObsLocGC99::print(std::ostream & os) const {
  os << "Gaspari-Cohn localization with lengthscale=" << rscale_;
}
 
// -----------------------------------------------------------------------------
 
}  // namespace lorenz95