/*

Copyright (C) 1996, 1997, 2002, 2003, 2004, 2005, 2006, 2007, 2008
              John W. Eaton

This file is part of Octave.

Octave 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.

Octave 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 Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <cfloat>

#include <sstream>

#include "DASPK.h"
#include "f77-fcn.h"
#include "lo-error.h"
#include "lo-math.h"
#include "quit.h"

typedef octave_idx_type (*daspk_fcn_ptr) (const double&, const double*,
			      const double*, const double&,
			      double*, octave_idx_type&, double*, octave_idx_type*);

typedef octave_idx_type (*daspk_jac_ptr) (const double&, const double*,
			      const double*, double*,
			      const double&, double*, octave_idx_type*);

typedef octave_idx_type (*daspk_psol_ptr) (const octave_idx_type&, const double&,
			       const double*, const double*,
			       const double*, const double&,
			       const double*, double*, octave_idx_type*,
			       double*, const double&, octave_idx_type&,
			       double*, octave_idx_type*);

extern "C"
{
  F77_RET_T
  F77_FUNC (ddaspk, DDASPK) (daspk_fcn_ptr, const octave_idx_type&, double&,
			     double*, double*, double&, const octave_idx_type*,
			     const double*, const double*, octave_idx_type&,
			     double*, const octave_idx_type&, octave_idx_type*, const octave_idx_type&,
			     const double*, const octave_idx_type*,
			     daspk_jac_ptr, daspk_psol_ptr);
}

static DAEFunc::DAERHSFunc user_fun;
static DAEFunc::DAEJacFunc user_jac;
static octave_idx_type nn;

static octave_idx_type
ddaspk_f (const double& time, const double *state, const double *deriv,
	  const double&, double *delta, octave_idx_type& ires, double *, octave_idx_type *)
{
  BEGIN_INTERRUPT_WITH_EXCEPTIONS;

  ColumnVector tmp_deriv (nn);
  ColumnVector tmp_state (nn);
  ColumnVector tmp_delta (nn);

  for (octave_idx_type i = 0; i < nn; i++)
    {
      tmp_deriv.elem (i) = deriv [i];
      tmp_state.elem (i) = state [i];
    }

  tmp_delta = user_fun (tmp_state, tmp_deriv, time, ires);

  if (ires >= 0)
    {
      if (tmp_delta.length () == 0)
	ires = -2;
      else
	{
	  for (octave_idx_type i = 0; i < nn; i++)
	    delta [i] = tmp_delta.elem (i);
	}
    }

  END_INTERRUPT_WITH_EXCEPTIONS;

  return 0;
}

//NEQ, T, Y, YPRIME, SAVR, WK, CJ, WGHT,
//C                          WP, IWP, B, EPLIN, IER, RPAR, IPAR)

static octave_idx_type
ddaspk_psol (const octave_idx_type&, const double&, const double *,
	     const double *, const double *, const double&,
	     const double *, double *, octave_idx_type *, double *,
	     const double&, octave_idx_type&, double *, octave_idx_type*)
{
  BEGIN_INTERRUPT_WITH_EXCEPTIONS;

  abort ();

  END_INTERRUPT_WITH_EXCEPTIONS;

  return 0;
}


static octave_idx_type
ddaspk_j (const double& time, const double *state, const double *deriv,
	  double *pd, const double& cj, double *, octave_idx_type *)
{
  BEGIN_INTERRUPT_WITH_EXCEPTIONS;

  // FIXME -- would be nice to avoid copying the data.

  ColumnVector tmp_state (nn);
  ColumnVector tmp_deriv (nn);

  for (octave_idx_type i = 0; i < nn; i++)
    {
      tmp_deriv.elem (i) = deriv [i];
      tmp_state.elem (i) = state [i];
    }

  Matrix tmp_pd = user_jac (tmp_state, tmp_deriv, time, cj);

  for (octave_idx_type j = 0; j < nn; j++)
    for (octave_idx_type i = 0; i < nn; i++)
      pd [nn * j + i] = tmp_pd.elem (i, j);

  END_INTERRUPT_WITH_EXCEPTIONS;

  return 0;
}

ColumnVector
DASPK::do_integrate (double tout)
{
  // FIXME -- should handle all this option stuff just once
  // for each new problem.

  ColumnVector retval;

  if (! initialized || restart || DAEFunc::reset|| DASPK_options::reset)
    {
      integration_error = false;

      initialized = true;

      info.resize (20);

      for (octave_idx_type i = 0; i < 20; i++)
	info(i) = 0;

      pinfo = info.fortran_vec ();

      octave_idx_type n = size ();

      nn = n;

      info(0) = 0;

      if (stop_time_set)
	{
	  rwork(0) = stop_time;
	  info(3) = 1;
	}
      else
	info(3) = 0;

      px = x.fortran_vec ();
      pxdot = xdot.fortran_vec ();

      // DAEFunc

      user_fun = DAEFunc::function ();
      user_jac = DAEFunc::jacobian_function ();

      if (user_fun)
	{
	  octave_idx_type ires = 0;

	  ColumnVector res = (*user_fun) (x, xdot, t, ires);

	  if (res.length () != x.length ())
	    {
	      (*current_liboctave_error_handler)
		("daspk: inconsistent sizes for state and residual vectors");

	      integration_error = true;
	      return retval;
	    }
	}
      else
	{
	  (*current_liboctave_error_handler)
	    ("daspk: no user supplied RHS subroutine!");

	  integration_error = true;
	  return retval;
	}
  
      info(4) = user_jac ? 1 : 0;

      DAEFunc::reset = false;

      octave_idx_type eiq = enforce_inequality_constraints ();
      octave_idx_type ccic = compute_consistent_initial_condition ();
      octave_idx_type eavfet = exclude_algebraic_variables_from_error_test ();

      liw = 40 + n;
      if (eiq == 1 || eiq == 3)
	liw += n;
      if (ccic == 1 || eavfet == 1)
	liw += n;

      lrw = 50 + 9*n + n*n;
      if (eavfet == 1)
	lrw += n;

      iwork.resize (liw);
      rwork.resize (lrw);

      piwork = iwork.fortran_vec ();
      prwork = rwork.fortran_vec ();

      // DASPK_options

      abs_tol = absolute_tolerance ();
      rel_tol = relative_tolerance ();

      octave_idx_type abs_tol_len = abs_tol.length ();
      octave_idx_type rel_tol_len = rel_tol.length ();

      if (abs_tol_len == 1 && rel_tol_len == 1)
	{
	  info(1) = 0;
	}
      else if (abs_tol_len == n && rel_tol_len == n)
	{
	  info(1) = 1;
	}
      else
	{
	  (*current_liboctave_error_handler)
	    ("daspk: inconsistent sizes for tolerance arrays");

	  integration_error = true;
	  return retval;
	}

      pabs_tol = abs_tol.fortran_vec ();
      prel_tol = rel_tol.fortran_vec ();

      double hmax = maximum_step_size ();
      if (hmax >= 0.0)
	{
	  rwork(1) = hmax;
	  info(6) = 1;
	}
      else
	info(6) = 0;

      double h0 = initial_step_size ();
      if (h0 >= 0.0)
	{
	  rwork(2) = h0;
	  info(7) = 1;
	}
      else
	info(7) = 0;

      octave_idx_type maxord = maximum_order ();
      if (maxord >= 0)
	{
	  if (maxord > 0 && maxord < 6)
	    {
	      info(8) = 1;
	      iwork(2) = maxord;
	    }
	  else
	    {
	      (*current_liboctave_error_handler)
		("daspk: invalid value for maximum order");
	      integration_error = true;
	      return retval;
	    }
	}

      switch (eiq)
	{
	case 1:
	case 3:
	  {
	    Array<octave_idx_type> ict = inequality_constraint_types ();

	    if (ict.length () == n)
	      {
		for (octave_idx_type i = 0; i < n; i++)
		  {
		    octave_idx_type val = ict(i);
		    if (val < -2 || val > 2)
		      {
			(*current_liboctave_error_handler)
			  ("daspk: invalid value for inequality constraint type");
			integration_error = true;
			return retval;
		      }
		    iwork(40+i) = val;
		  }
	      }
	    else
	      {
		(*current_liboctave_error_handler)
		  ("daspk: inequality constraint types size mismatch");
		integration_error = true;
		return retval;
	      }
	  }
	  // Fall through...

	case 0:
	case 2:
	  info(9) = eiq;
	  break;

	default:
	  (*current_liboctave_error_handler)
	    ("daspk: invalid value for enforce inequality constraints option");
	  integration_error = true;
	  return retval;
	}

      if (ccic)
	{
	  if (ccic == 1)
	    {
	      // FIXME -- this code is duplicated below.

	      Array<octave_idx_type> av = algebraic_variables ();

	      if (av.length () == n)
		{
		  octave_idx_type lid;
		  if (eiq == 0 || eiq == 2)
		    lid = 40;
		  else if (eiq == 1 || eiq == 3)
		    lid = 40 + n;
		  else
		    abort ();

		  for (octave_idx_type i = 0; i < n; i++)
		    iwork(lid+i) = av(i) ? -1 : 1;
		}
	      else
		{
		  (*current_liboctave_error_handler)
		    ("daspk: algebraic variables size mismatch");
		  integration_error = true;
		  return retval;
		}
	    }
	  else if (ccic != 2)
	    {
	      (*current_liboctave_error_handler)
		("daspk: invalid value for compute consistent initial condition option");
	      integration_error = true;
	      return retval;
	    }

	  info(10) = ccic;
	}

      if (eavfet)
	{
	  info(15) = 1;

	  // FIXME -- this code is duplicated above.

	  Array<octave_idx_type> av = algebraic_variables ();

	  if (av.length () == n)
	    {
	      octave_idx_type lid;
	      if (eiq == 0 || eiq == 2)
		lid = 40;
	      else if (eiq == 1 || eiq == 3)
		lid = 40 + n;
	      else
		abort ();

	      for (octave_idx_type i = 0; i < n; i++)
		iwork(lid+i) = av(i) ? -1 : 1;
	    }
	}

      if (use_initial_condition_heuristics ())
	{
	  Array<double> ich = initial_condition_heuristics ();

	  if (ich.length () == 6)
	    {
	      iwork(31) = NINTbig (ich(0));
	      iwork(32) = NINTbig (ich(1));
	      iwork(33) = NINTbig (ich(2));
	      iwork(34) = NINTbig (ich(3));

	      rwork(13) = ich(4);
	      rwork(14) = ich(5);
	    }
	  else
	    {
	      (*current_liboctave_error_handler)
		("daspk: invalid initial condition heuristics option");
	      integration_error = true;
	      return retval;
	    }

	  info(16) = 1;
	}

      octave_idx_type pici = print_initial_condition_info ();
      switch (pici)
	{
	case 0:
	case 1:
	case 2:
	  info(17) = pici;
	  break;

	default:
	  (*current_liboctave_error_handler)
	    ("daspk: invalid value for print initial condition info option");
	  integration_error = true;
	  return retval;
	  break;
	}

      DASPK_options::reset = false;

      restart = false;
    }

  static double *dummy = 0;
  static octave_idx_type *idummy = 0;

  F77_XFCN (ddaspk, DDASPK, (ddaspk_f, nn, t, px, pxdot, tout, pinfo,
			     prel_tol, pabs_tol, istate, prwork, lrw,
			     piwork, liw, dummy, idummy, ddaspk_j,
			     ddaspk_psol));

  switch (istate)
    {
    case 1: // A step was successfully taken in intermediate-output
	    // mode. The code has not yet reached TOUT.
    case 2: // The integration to TSTOP was successfully completed
	    // (T=TSTOP) by stepping exactly to TSTOP.
    case 3: // The integration to TOUT was successfully completed
	    // (T=TOUT) by stepping past TOUT.  Y(*) is obtained by
	    // interpolation.  YPRIME(*) is obtained by interpolation.
    case 4: // The initial condition calculation, with
	    // INFO(11) > 0, was successful, and INFO(14) = 1.
	    // No integration steps were taken, and the solution
	    // is not considered to have been started.
      retval = x;
      t = tout;
      break;

    case -1: // A large amount of work has been expended.  (~500 steps).
    case -2: // The error tolerances are too stringent.
    case -3: // The local error test cannot be satisfied because you
	     // specified a zero component in ATOL and the
	     // corresponding computed solution component is zero.
	     // Thus, a pure relative error test is impossible for
	     // this component.
    case -6: // DDASPK had repeated error test failures on the last
	     // attempted step.
    case -7: // The corrector could not converge.
    case -8: // The matrix of partial derivatives is singular.
    case -9: // The corrector could not converge.  There were repeated
	     // error test failures in this step.
    case -10: // The corrector could not converge because IRES was
	      // equal to minus one.
    case -11: // IRES equal to -2 was encountered and control is being
	      // returned to the calling program.
    case -12: // DDASPK failed to compute the initial YPRIME.
    case -13: // Unrecoverable error encountered inside user's
	      // PSOL routine, and control is being returned to
	      // the calling program.
    case -14: // The Krylov linear system solver could not
	      // achieve convergence.
    case -33: // The code has encountered trouble from which it cannot
	      // recover. A message is printed explaining the trouble
	      // and control is returned to the calling program. For
	      // example, this occurs when invalid input is detected.
      integration_error = true;
      break;

    default:
      integration_error = true;
      (*current_liboctave_error_handler)
	("unrecognized value of istate (= %d) returned from ddaspk",
	 istate);
      break;
    }

  return retval;
}

Matrix
DASPK::do_integrate (const ColumnVector& tout)
{
  Matrix dummy;
  return integrate (tout, dummy);
}

Matrix
DASPK::integrate (const ColumnVector& tout, Matrix& xdot_out)
{
  Matrix retval;

  octave_idx_type n_out = tout.capacity ();
  octave_idx_type n = size ();

  if (n_out > 0 && n > 0)
    {
      retval.resize (n_out, n);
      xdot_out.resize (n_out, n);

      for (octave_idx_type i = 0; i < n; i++)
	{
	  retval.elem (0, i) = x.elem (i);
	  xdot_out.elem (0, i) = xdot.elem (i);
	}

      for (octave_idx_type j = 1; j < n_out; j++)
	{
	  ColumnVector x_next = do_integrate (tout.elem (j));

	  if (integration_error)
	    return retval;

	  for (octave_idx_type i = 0; i < n; i++)
	    {
	      retval.elem (j, i) = x_next.elem (i);
	      xdot_out.elem (j, i) = xdot.elem (i);
	    }
	}
    }

  return retval;
}

Matrix
DASPK::do_integrate (const ColumnVector& tout, const ColumnVector& tcrit)
{
  Matrix dummy;
  return integrate (tout, dummy, tcrit);
}

Matrix
DASPK::integrate (const ColumnVector& tout, Matrix& xdot_out,
		  const ColumnVector& tcrit) 
{
  Matrix retval;

  octave_idx_type n_out = tout.capacity ();
  octave_idx_type n = size ();

  if (n_out > 0 && n > 0)
    {
      retval.resize (n_out, n);
      xdot_out.resize (n_out, n);

      for (octave_idx_type i = 0; i < n; i++)
	{
	  retval.elem (0, i) = x.elem (i);
	  xdot_out.elem (0, i) = xdot.elem (i);
	}

      octave_idx_type n_crit = tcrit.capacity ();

      if (n_crit > 0)
	{
	  octave_idx_type i_crit = 0;
	  octave_idx_type i_out = 1;
	  double next_crit = tcrit.elem (0);
	  double next_out;
	  while (i_out < n_out)
	    {
	      bool do_restart = false;

	      next_out = tout.elem (i_out);
	      if (i_crit < n_crit)
		next_crit = tcrit.elem (i_crit);

	      bool save_output;
	      double t_out;

	      if (next_crit == next_out)
		{
		  set_stop_time (next_crit);
		  t_out = next_out;
		  save_output = true;
		  i_out++;
		  i_crit++;
		  do_restart = true;
		}
	      else if (next_crit < next_out)
		{
		  if (i_crit < n_crit)
		    {
		      set_stop_time (next_crit);
		      t_out = next_crit;
		      save_output = false;
		      i_crit++;
		      do_restart = true;
		    }
		  else
		    {
		      clear_stop_time ();
		      t_out = next_out;
		      save_output = true;
		      i_out++;
		    }
		}
	      else
		{
		  set_stop_time (next_crit);
		  t_out = next_out;
		  save_output = true;
		  i_out++;
		}

	      ColumnVector x_next = do_integrate (t_out);

	      if (integration_error)
		return retval;

	      if (save_output)
		{
		  for (octave_idx_type i = 0; i < n; i++)
		    {
		      retval.elem (i_out-1, i) = x_next.elem (i);
		      xdot_out.elem (i_out-1, i) = xdot.elem (i);
		    }
		}

	      if (do_restart)
		force_restart ();
	    }
	}
      else
	{
	  retval = integrate (tout, xdot_out);

	  if (integration_error)
	    return retval;
	}
    }

  return retval;
}

std::string
DASPK::error_message (void) const
{
  std::string retval;

  std::ostringstream buf;
  buf << t;
  std::string t_curr = buf.str ();

  switch (istate)
    {
    case 1:
      retval = "a step was successfully taken in intermediate-output mode.";
      break;

    case 2:
      retval = "integration completed by stepping exactly to TOUT";
      break;

    case 3:
      retval = "integration to tout completed by stepping past TOUT";
      break;

    case 4:
      retval = "initial condition calculation completed successfully";
      break;

    case -1:
      retval = std::string ("a large amount of work has been expended (t =")
	+ t_curr + ")";
      break;

    case -2:
      retval = "the error tolerances are too stringent";
      break;

    case -3:
      retval = std::string ("error weight became zero during problem. (t = ")
	+ t_curr
	+ "; solution component i vanished, and atol or atol(i) == 0)";
      break;

    case -6:
      retval = std::string ("repeated error test failures on the last attempted step (t = ")
	+ t_curr + ")";
      break;

    case -7:
      retval = std::string ("the corrector could not converge (t = ")
	+ t_curr + ")";
      break;

    case -8:
      retval = std::string ("the matrix of partial derivatives is singular (t = ")
	+ t_curr + ")";
      break;

    case -9:
      retval = std::string ("the corrector could not converge (t = ")
	+ t_curr + "; repeated test failures)";
      break;

    case -10:
      retval = std::string ("corrector could not converge because IRES was -1 (t = ")
	+ t_curr + ")";
      break;

    case -11:
      retval = std::string ("return requested in user-supplied function (t = ")
	+ t_curr + ")";
      break;

    case -12:
      retval = "failed to compute consistent initial conditions";
      break;

    case -13:
      retval = std::string ("unrecoverable error encountered inside user's PSOL function (t = ")
	+ t_curr + ")";
      break;

    case -14:
      retval = std::string ("the Krylov linear system solver failed to converge (t = ")
	+ t_curr + ")";
      break;

    case -33:
      retval = "unrecoverable error (see printed message)";
      break;

    default:
      retval = "unknown error state";
      break;
    }

  return retval;
}

/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/