simulation_init.cpp

/*
 * This file is part of OpenModelica.
 *
 * Copyright (c) 1998-2010, Linköpings University,
 * Department of Computer and Information Science,
 * SE-58183 Linköping, Sweden.
 *
 * All rights reserved.
 *
 * THIS PROGRAM IS PROVIDED UNDER THE TERMS OF THIS OSMC PUBLIC
 * LICENSE (OSMC-PL). ANY USE, REPRODUCTION OR DISTRIBUTION OF
 * THIS PROGRAM CONSTITUTES RECIPIENT'S ACCEPTANCE OF THE OSMC
 * PUBLIC LICENSE.
 *
 * The OpenModelica software and the Open Source Modelica
 * Consortium (OSMC) Public License (OSMC-PL) are obtained
 * from Linköpings University, either from the above address,
 * from the URL: http://www.ida.liu.se/projects/OpenModelica
 * and in the OpenModelica distribution.
 *
 * This program is distributed  WITHOUT ANY WARRANTY; without
 * even the implied warranty of  MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE, EXCEPT AS EXPRESSLY SET FORTH
 * IN THE BY RECIPIENT SELECTED SUBSIDIARY LICENSE CONDITIONS
 * OF OSMC-PL.
 *
 * See the full OSMC Public License conditions for more details.
 *
 */

#include "simulation_init.h"
#include "simulation_runtime.h"
#include "solver_main.h"
#include <math.h>

/*
 * This function calculates the residual value as the sum of squared residual equations.
 */

void leastSquare(long *nz, double *z, double *funcValue)
{
  int ind, indAct, indz;
  int startIndPar = 2*globalData->nStates+globalData->nAlgebraic+globalData->intVariables.nAlgebraic+globalData->boolVariables.nAlgebraic;

 for (ind=0, indAct=0, indz=0; ind<globalData->nStates; ind++)
    if (globalData->initFixed[indAct++]==0 )
          globalData->states[ind] = z[indz++];

  // for real parameters 
  for (ind=0,indAct=startIndPar; ind<globalData->nParameters; ind++, indAct++)
    if (globalData->initFixed[indAct]==0 and globalData->var_attr[indAct-globalData->nStates]==1)
      globalData->parameters[ind] = z[indz++];

  bound_parameters();
  functionODE();
  functionAlgebraics();

  initial_residual();

  for (ind=0, *funcValue=0; ind<globalData->nInitialResiduals; ind++)
    *funcValue += globalData->initialResiduals[ind]*globalData->initialResiduals[ind];

  if (sim_verbose >= LOG_INIT) {
    cout << "initial residual: " << *funcValue << endl;
  }
}

/** function reportResidualValue
 **
 ** Returns -1 if residual is non-zero and prints appropriate error message.
 **/

int reportResidualValue(double funcValue)
{
  int i;
  if (funcValue > 1e-5) {
    std::cerr << "Error in initialization. System of initial equations are not consistent." << std::endl;
    std::cerr << "(Least Square function value is " << funcValue << ")" << std::endl;
    for (i=0; i<globalData->nInitialResiduals; i++) {
      if (fabs(globalData->initialResiduals[i]) > 1e-6) {
        cout << "residual[" << i << "] = " << globalData->initialResiduals[i] << endl;
      }
    }
    return 1;
  }
  return 0;
}

/** function: newuoa_initialization
 **
 ** This function performs initialization using the newuoa function, which is
 ** a trust region method that forms quadratic models by interpolation.
 **/

int newuoa_initialization(long& nz,double *z)
{
  long IPRINT = sim_verbose >= LOG_INIT? 2 : 0;
  long MAXFUN=50000;
  double RHOEND=1.0e-6;
  double RHOBEG=10; // This should be about one tenth of the greatest
        // expected value of a variable. Perhaps the nominal
        // value can be used for this.
  long NPT = 2*nz+1;
  double *W = new double[(NPT+13)*(NPT+nz)+3*nz*(nz+3)/2];
  NEWUOA(&nz,&NPT,z,&RHOBEG,&RHOEND,&IPRINT,&MAXFUN,W,leastSquare);

  // Calculate the residual to verify that equations are consistent.
  double funcValue;
  leastSquare(&nz,z,&funcValue);


  delete [] W;
  return reportResidualValue(funcValue);
}

/** function: simplex_initialization.
 **
 ** This function performs initialization by using the simplex algorithm.
 ** This does not require a jacobian for the residuals.
 **/

int simplex_initialization(long& nz,double *z)
{
  int ind;
  double funcValue;
  double *STEP=(double*) malloc(nz*sizeof(double));
  double *VAR=(double*) malloc(nz*sizeof(double));

  /* Start with stepping .5 in each direction. */
  for (ind=0;ind<nz;ind++)
  {
    STEP[ind] = 1.0;
    VAR[ind]  = 0.0;
  }

   double STOPCR,SIMP;
   long IPRINT, NLOOP,IQUAD,IFAULT,MAXF;
//C  Set max. no. of function evaluations = 5000, print every 100.

      MAXF = 50 * nz;
      IPRINT = sim_verbose >= LOG_INIT ? 100 : -1;

//C  Set value for stopping criterion.   Stopping occurs when the
//C  standard deviation of the values of the objective function at
//C  the points of the current simplex < stopcr.

      STOPCR = 1.e-3;
      NLOOP = 2*MAXF;

//C  Fit a quadratic surface to be sure a minimum has been found.

      IQUAD = 0;

//C  As function value is being evaluated in DOUBLE PRECISION, it
//C  should be accurate to about 15 decimals.   If we set simp = 1.d-6,
//C  we should get about 9 dec. digits accuracy in fitting the surface.

      SIMP = 1.e-12;
//C  Now call NELMEAD to do the work.
  
  leastSquare(&nz,z,&funcValue);

  if ( fabs(funcValue) != 0){
      NELMEAD(z,STEP,&nz,&funcValue,&MAXF,&IPRINT,&STOPCR,
           &NLOOP,&IQUAD,&SIMP,VAR,leastSquare,&IFAULT);
  }else{
      if (sim_verbose >= LOG_INIT){
          printf("Result of leastSquare method = %g. The initial guess fits to the system\n",funcValue);
      }
  }

  if (IFAULT == 1) {
    leastSquare(&nz,z,&funcValue);
    if (funcValue > SIMP) {
      printf("Error in initialization. Solver iterated %d times without finding a solution\n",(int)MAXF);
      return -1;
    }
  } else if(IFAULT == 2 ) {
    printf("Error in initialization. Inconsistent initial conditions.\n");
    return -1;
  } else if (IFAULT == 3) {
    printf("Error in initialization. Number of initial values to calculate < 1\n");
    return -1;
  } else if (IFAULT == 4) {
    printf("Error in initialization. Internal error, NLOOP < 1.\n");
    return -1;
  }
  return reportResidualValue(funcValue);
}

/* function: initialize
 *
 * Perform initialization of the problem. It reads the global variable
 * globalData->initFixed to find out which variables are fixed.
 * It uses the generated function initial_residual, which calcualtes the
 * residual of all equations (both continuous time eqns and initial eqns).
 */

int initialize(const std::string init_method)
{
  long nz;
  int ind, indAct, indz;

  for (ind=0, nz=0; ind<globalData->nStates; ind++){
    if (globalData->initFixed[ind]==0){
        if (sim_verbose >= LOG_INIT)
            printf("State %s is unfixed.\n",globalData->statesNames[ind].name);

        nz++;
    }
  }

  int startIndPar = 2*globalData->nStates+globalData->nAlgebraic+globalData->intVariables.nAlgebraic+globalData->boolVariables.nAlgebraic;
  int endIndPar = startIndPar+globalData->nParameters;
  for (ind=startIndPar;ind<endIndPar; ind++){
    if (globalData->initFixed[ind]==0 and globalData->var_attr[ind-globalData->nStates]==1){
        if (sim_verbose >= LOG_INIT)
          printf("Parameter %s is unfixed.\n",globalData->parametersNames[ind-startIndPar].name);
        nz++;
    }
  }

  if (sim_verbose >= LOG_INIT) {
    cout << "Initialization by method: " << init_method << endl;
    cout << "fixed attribute for states:" << endl;
    for(int i=0;i<globalData->nStates; i++) {
      cout << globalData->statesNames[i].name << "(fixed=" << (globalData->initFixed[i]?"true":"false") << ")"
      << endl;
    }
    cout << "number of non-fixed variables: " << nz << endl;
  }

  // No initial values to calculate.
  if (nz ==  0) {
    if (sim_verbose >= LOG_INIT) {
      cout << "No initial values to calculate" << endl;
    }
    return 0;
  }

  double *z= new double[nz];
  if(z == NULL) {return -1;}
  /* Fill z with the non-fixed variables from x and p*/
  for (ind=0, indAct=0, indz=0; ind<globalData->nStates; ind++){
    if (globalData->initFixed[indAct++]==0)
      z[indz++] = globalData->states[ind];
  }
  // for real parameters
  for (ind=0,indAct=startIndPar; ind<globalData->nParameters; ind++) {
    if (globalData->initFixed[indAct++]==0 and globalData->var_attr[indAct-globalData->nStates]==1)
      z[indz++] =  globalData->parameters[ind];
  }

  int retVal=0;
  if (init_method == std::string("simplex")) {
    retVal = simplex_initialization(nz,z);
  } else if (init_method == std::string("newuoa")) { // Better name ?
    retVal = newuoa_initialization(nz,z);
  } else {
    std::cerr << "unrecognized option -im " << init_method << std::endl;
    std::cerr << "current options are: simplex or newuoa" << std::endl;
    retVal= -1;
  }
  delete [] z;
  return retVal;
}

int
main_initialize(const std::string* method)
{

  std::string init_method;

  if (method == NULL)
    {
      init_method = std::string("simplex");
    }
  else
    {
      init_method = *method;
    }

  saveall();
  initial_function();
  update_DAEsystem();
  if (sim_verbose >= LOG_SOLVER)
    {
      sim_result->emit();
    }
  // do some initial stuff
  globalData->init = 1;
  initial_function();
  if (sim_verbose >= LOG_SOLVER)
    {
      sim_result->emit();
    }
  //saveall();
  //update_DAEsystem();

  storeExtrapolationData();
  storeExtrapolationData();

  if (sim_verbose >= LOG_SOLVER)
    {
      sim_result->emit();
    }

  //first try with the given method as default simplex and
  //then try with the other one
  int retVal = 0;
  retVal = initialize(init_method);
  if (retVal != 0)
    {
      if (init_method == std::string("simplex"))
        {
          init_method = std::string("newuoa");
          retVal = initialize(init_method);
        }
      else if (init_method == std::string("newuoa"))
        {
          init_method = std::string("simplex");
          retVal = initialize(init_method);
        }
      if (retVal != 0)
        {
          printf("Initialization of the current initial set of equations and initial guesses fails!\n");
          printf("Try with better Initial guesses for the states.\n");
          retVal = 1;
        }
    }

  saveall();
  storeExtrapolationData();
  storeExtrapolationData();

  if (sim_verbose >= LOG_SOLVER)
    {
      sim_result->emit();
    }

  update_DAEsystem();
  SaveZeroCrossings();
  saveall();
  if (sim_verbose >= LOG_SOLVER)
    {
      sim_result->emit();
    }
  storeExtrapolationData();
  storeExtrapolationData();
  globalData->init = 0;
  return retVal;
}