ObsLocGC99.cc

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/*
 * (C) Copyright 2020 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 "ioda/core/ObsLocGC99.h"
 
#include "eckit/config/Configuration.h"
#include "eckit/exception/Exceptions.h"
 
#include "ioda/ObsSpace.h"
#include "ioda/ObsVector.h"
 
#include "oops/generic/gc99.h"
#include "oops/interface/ObsLocalization.h"
 
// -----------------------------------------------------------------------------
namespace ioda {
 
// -----------------------------------------------------------------------------
 
ObsLocGC99::ObsLocGC99(const eckit::Configuration & config, const ObsSpace & obsdb)
  : obsdb_(obsdb),
    rscale_(config.getDouble("lengthscale"))
{
}
 
// -----------------------------------------------------------------------------
 
ObsLocGC99::~ObsLocGC99() {}
 
// -----------------------------------------------------------------------------
 
void ObsLocGC99::multiply(ObsVector & dy) const {
  const std::vector<double> & obsdist = obsdb_.obsdist();
  const size_t nlocs = dy.nlocs();
  const size_t nvars = dy.nvars();
 
  // create a temporary vector with localization values
  // (by putting in an ObsVector, multiplication respects the missing values)
  ObsVector gcVec(dy);
  gcVec.zero();
  for (size_t jloc = 0; jloc < nlocs; ++jloc) {
    double gc = oops::gc99(obsdist[jloc] / rscale_);
    // obsdist is calculated at each location; need to update R for each variable
    for (size_t jvar = 0; jvar < nvars; ++jvar) {
      gcVec[jvar + jloc * nvars] = gc;
    }
  }
 
  dy *= gcVec;
}
 
// -----------------------------------------------------------------------------
 
void ObsLocGC99::print(std::ostream & os) const {
  os << "Gaspari-Cohn localization with " << rscale_ << " lengthscale" << std::endl;
}
 
// -----------------------------------------------------------------------------
 
}  // namespace ioda