ObsSpaceBase.cc

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/*
 * (C) Copyright 2018  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 "oops/base/ObsSpaceBase.h"
 
#include "eckit/config/LocalConfiguration.h"
#include "eckit/exception/Exceptions.h"
 
#include "oops/util/DateTime.h"
#include "oops/util/Duration.h"
#include "oops/util/Logger.h"
 
namespace oops {
 
// -----------------------------------------------------------------------------
int ObsSpaceBase::instances_ = 0;
// -----------------------------------------------------------------------------
 
ObsSpaceBase::ObsSpaceBase(const eckit::Configuration & conf, const eckit::mpi::Comm & comm,
                           const util::DateTime & bgn, const util::DateTime & end)
  : winbgn_(bgn), winend_(end), instance_(++instances_) {
//
// Determine seed for random number generator that is reproducible when re-running
// but does not repeat itself over analysis cycles, ensemble members or obs type
//
  util::DateTime ref(1623, 6, 19, 0, 0, 0);
  ASSERT(winbgn_ > ref);
  util::Duration dt(winbgn_ - ref);
  seed_ = dt.toSeconds();
 
  // Won't repeat if more seconds between analysis cycles than members in EDA
  seed_ += conf.getInt("obs perturbations seed", 0);
 
//             31622400 seconds max in 1 year
//          12197962800 seed at this step for 2010-01-01T03:00:00Z
  seed_ += 100000000000 * instance_;
 
  Log::debug() << "ObsSpaceBase: seed = " << seed_ << std::endl;
}
 
// -----------------------------------------------------------------------------
 
}  // namespace oops