Ifpack2_Details_Chebyshev_Weights.hpp

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// @HEADER
// *****************************************************************************
//       Ifpack2: Templated Object-Oriented Algebraic Preconditioner Package
//
// Copyright 2009 NTESS and the Ifpack2 contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#ifndef IFPACK2_DETAILS_CHEBYSHEV_WEIGHTS_HPP
#define IFPACK2_DETAILS_CHEBYSHEV_WEIGHTS_HPP

#include <stdexcept>
#include <vector>
#include "Teuchos_StandardParameterEntryValidators.hpp"


namespace Ifpack2 {
namespace Details {

template <typename ScalarType>
std::vector<ScalarType>
optimalWeightsImpl(const int chebyOrder) {
  if (chebyOrder == 0) {
    return {};
  }
  if (chebyOrder == 1) {
    return {
        1.12500000000000,
    };
  }

  if (chebyOrder == 2) {
    return {
        1.02387287570313,
        1.26408905371085,
    };
  }

  if (chebyOrder == 3) {
    return {
        1.00842544782028,
        1.08867839208730,
        1.33753125909618,
    };
  }

  if (chebyOrder == 4) {
    return {
        1.00391310427285,
        1.04035811188593,
        1.14863498546254,
        1.38268869241000,
    };
  }

  if (chebyOrder == 5) {
    return {
        1.00212930146164,
        1.02173711549260,
        1.07872433192603,
        1.19810065292663,
        1.41322542791682,
    };
  }

  if (chebyOrder == 6) {
    return {
        1.00128517255940,
        1.01304293035233,
        1.04678215124113,
        1.11616489419675,
        1.23829020218444,
        1.43524297106744,
    };
  }

  if (chebyOrder == 7) {
    return {
        1.00083464397912,
        1.00843949430122,
        1.03008707768713,
        1.07408384092003,
        1.15036186707366,
        1.27116474046139,
        1.45186658649364,
    };
  }

  if (chebyOrder == 8) {
    return {
        1.00057246631197,
        1.00577427662415,
        1.02050187922941,
        1.05019803444565,
        1.10115572984941,
        1.18086042806856,
        1.29838585382576,
        1.46486073151099,
    };
  }

  if (chebyOrder == 9) {
    return {
        1.00040960072832,
        1.00412439506106,
        1.01460212148266,
        1.03561113626671,
        1.07139972529194,
        1.12688273710962,
        1.20785219140729,
        1.32121930716746,
        1.47529642820699,
    };
  }

  if (chebyOrder == 10) {
    return {
        1.00030312229652,
        1.00304840660796,
        1.01077022715387,
        1.02619011597640,
        1.05231724933755,
        1.09255743207549,
        1.15083376663972,
        1.23172250870894,
        1.34060802024460,
        1.48386124407011,
    };
  }

  if (chebyOrder == 11) {
    return {
        1.00023058595209,
        1.00231675024028,
        1.00817245396304,
        1.01982986566342,
        1.03950210235324,
        1.06965042700541,
        1.11305754295742,
        1.17290876275564,
        1.25288300576792,
        1.35725579919519,
        1.49101672564139,
    };
  }

  if (chebyOrder == 12) {
    return {
        1.00017947200828,
        1.00180189139619,
        1.00634861907307,
        1.01537864566306,
        1.03056942830760,
        1.05376019693943,
        1.08699862592072,
        1.13259183097913,
        1.19316273358172,
        1.27171293675110,
        1.37169337969799,
        1.49708418575562,
    };
  }

  if (chebyOrder == 13) {
    return {
        1.00014241921559,
        1.00142906932629,
        1.00503028986298,
        1.01216910518495,
        1.02414874342792,
        1.04238158880820,
        1.06842008128700,
        1.10399010936759,
        1.15102748242645,
        1.21171811910125,
        1.28854264865128,
        1.38432619380991,
        1.50229418757368,
    };
  }

  if (chebyOrder == 14) {
    return {
        1.00011490538261,
        1.00115246376914,
        1.00405357333264,
        1.00979590573153,
        1.01941300472994,
        1.03401425035436,
        1.05480599606629,
        1.08311420301813,
        1.12040891660892,
        1.16833095655446,
        1.22872122288238,
        1.30365305707817,
        1.39546814053678,
        1.50681646209583,
    };
  }

  if (chebyOrder == 15) {
    return {
        1.00009404750752,
        1.00094291696343,
        1.00331449056444,
        1.00800294833816,
        1.01584236259140,
        1.02772083317705,
        1.04459535422831,
        1.06750761206125,
        1.09760092545889,
        1.13613855366157,
        1.18452361426236,
        1.24432087304475,
        1.31728069083392,
        1.40536543893560,
        1.51077872501845,
    };
  }

  if (chebyOrder == 16) {
    return {
        1.00007794828179,
        1.00078126847253,
        1.00274487974401,
        1.00662291017015,
        1.01309858836971,
        1.02289448329337,
        1.03678321409983,
        1.05559875719896,
        1.08024848405560,
        1.11172607131497,
        1.15112543431072,
        1.19965584614973,
        1.25865841744946,
        1.32962412656664,
        1.41421360695576,
        1.51427891730346,
    };
  }

  TEUCHOS_TEST_FOR_EXCEPTION(
      true, std::runtime_error,
      "Ifpack2::Details::optimalWeightsImpl::"
      "Requested Chebyshev order exceeds maximum of 16.");
}

}  // namespace Details
}  // namespace Ifpack2

#endif  // IFPACK2_DETAILS_CHEBYSHEV_WEIGHTS_HPP