package joptima;

import joptima.fortran.*;

/**
 * An object-oriented wrapper for UNCMIN Fortran-oid multi-variable
 * function minimization routines.
 * All the 1980's-paradigm ugliness is encapsulated within this class.
 * If it ain't broken, don't fix it... :)
 *
 * @author Dejan Vucinic 
 */
public class Minimizer implements Uncmin_methods {

  private int dimension;
  private Parameter[] parameters;
  private Minimizable function;

  public Minimizer(Minimizable function) {
    this.function = function;
    parameters = function.getParameters();
    dimension = parameters.length;
  }

  public void minimize() throws OptimizationException {

    double[] x0 = new double[dimension + 1]; // initial values
    int info[] = new int[2]; // return code
    double x[] = new double[dimension + 1]; // current parameter values
    double f[] = new double[2]; // current function value
    double g[] = new double[dimension + 1]; // gradient
    double a[][] = new double[dimension + 1][dimension + 1]; // hessian
    double udiag[] = new double[dimension + 1]; // who knows

    double typsiz[] = new double[dimension + 1];
    double fscale[] = new double[2];
    int method[] = new int[2];
    int iexp[] = new int[2];
    int msg[] = new int[2];
    int ndigit[] = new int[2];
    int itnlim[] = new int[2];
    int iagflg[] = new int[2];
    int iahflg[] = new int[2];
    double dlt[] = new double[2];
    double gradtl[] = new double[2];
    double stepmx[] = new double[2];
    double steptl[] = new double[2];

    Uncmin_f77.dfault_f77(dimension,x0,typsiz,fscale,method,iexp,
                          msg,ndigit,itnlim,iagflg,iahflg,
                          dlt,gradtl,stepmx,steptl);

    // iagflg[1] = 0;
    // iahflg[1] = 0;
    // iexp[1] = 0;
    // itnlim[1] = 50;
    // fscale[1] = 1;

    try {
      // Copy the initial parameters.
      for (int i = 0; i < dimension; i++) x0[i + 1] = parameters[i].get();

      // Run the minimization.
      Uncmin_f77.optif9_f77(dimension,x0,this,typsiz,fscale,method,iexp,
                            msg,ndigit,itnlim,iagflg,iahflg,
                            dlt,gradtl,stepmx,steptl,
                            x,f,g,info,a,udiag);
    } catch (IllegalAccessException iae) {
      throw new OptimizationException(iae);
    }

  }

  public double f_to_minimize(double[] x) {
    try {
      for (int i = 0; i < dimension; i++) parameters[i].set(x[i + 1]);
    } catch (IllegalAccessException iae) {
      iae.printStackTrace();
    }
    return function.calculate();
  }

  public void gradient(double x[], double g[]) { }

  public void hessian(double x[], double h[][]) { }

}