FastCalibration.hpp

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// This file is part of GranOO, a workbench for DEM simulation.
//
// Author(s)    : - Jean-luc CHARLES I2M-DuMAS/ENSAM Talence France
//                  <jean-luc.charles@ensam.eu>
//                - Damien ANDRE     SPCTS/ENS Ceramique industrielle, Limoges France
//                  <damien.andre@unilim.fr>
//                - Jeremie GIRARDOT I2M-DuMAS/ENSAM Talence France
//                  <jeremie.girardot@ensam.eu>
//                - Cedric Hubert    LAMIH/UVHC Valenciennes France
//                  <cedric.hubert@univ-valenciennes.fr>
//                - Ivan IORDANOFF   I2M-DuMAS-MPI/ENSAM Talence France
//                  <ivan.iordanoff@ensam.eu>
//                - Truong Thi NGUYEN  SPCTS, Limoges France
//                  <truong_thi.nguyen@unilim.fr>
//
// Copyright (C) 2008-2016 JL. CHARLES, D. ANDRE, I. IORDANOFF, J. GIRARDOT, Truong Thi NGUYEN
//
// The magic numbers used in the following algorithm were found by Truong Thi NGUYEN !
// The C++ version was implemented by DA.
//
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
#ifndef _LibAlgo_FastCalibration_HPP
#define _LibAlgo_FastCalibration_HPP
 
 
#include <array>
#include <complex>
 
 
namespace GranOO3
{
  namespace Algo
  {
 
    // lowercase class name : "fast_calibration"
    namespace FastCalibration
    {
 
      // This is magic numbers
      const std::array<double,4 > params_a1{ 0.42927654,-0.18406061, 0.37603434, 0.02089117};
      const std::array<double,4 > params_b1{-0.49868929, 0.50000024, 0.42710086,-0.08271247};
      const std::array<double,4 > params_c1{ 0.25794931,-0.49710941, 0.51427798,-0.10744844};
      const std::array<double,4 > params_d1{-0.10526749, 0.16929038, 0.59430784,-0.13338102};
 
      const std::array<double,4 > params_a2{-2.43078868e-02, 1.47594889e-02,-2.03651119e-03, 6.88939912e-05};
      const std::array<double,4 > params_b2{ 0.23544764,-0.15279903, 0.02172656,-0.00075681    };
      const std::array<double,4 > params_c2{-0.39811319, 0.26217126,-0.03078207, 0.00110456    };
      const std::array<double,4 > params_d2{ 0.02003125, 0.01309331, 0.01443429,-0.00053369    };
 
      const std::array<double,10> params_k{-0.56467597, 0.20824953,-0.0076038, 0.67696577, 0.09327836,-0.02297966, 0.00095033,-0.73897768, 0.08437881,-0.00239614};
 
      // some math functions
      double f_tanh(const double x,  const std::array<double,4>& array);
      double f_3rd_order(const double x, const std::array<double,4>& array);
      double f_EM_Em_Rm(const double x, const double y, const std::array<double,4>& array);
      double f_k_Cn_Rm(const double x, const double y, const std::array<double,10>& array);
 
      std::array<std::complex<double>,3> cubic_solve(const std::array<double,4>& array);
      std::array<double,4> compute_param_elastic_Num(const double cn);
      std::array<double,4> compute_param_elastic_Em(const double cn);
      double compute_Rm(const std::array<double,4>& param, const double NuM);
 
      // This is the main function interface, it takes as argument :
      // - EM  : Macroscopic Young's modulus (Pa)
      // - NuM : Macroscopic Poisson's ration
      // - SM  : Macroscopic failure strength (Pa)
      // This function returns
      // - Em : Microscopic Young's modulus
      // - Rm : Microscopic radius ratio
      // - Sm : Microscopic  failure strength
      void compute(const double EM, const double NuM, const double SM, const double cn, double& Em, double& Rm, double& Sm);
 
    }
 
  }
}
 
#endif